WO1996030381A1

WO1996030381A1 - Immunosuppressive agents

Info

Publication number: WO1996030381A1
Application number: PCT/DK1996/000124
Authority: WO
Inventors: Frank Winther Rasmussen; Poul Strange; Jens Breinholt
Original assignee: Novo Nordisk A/S
Priority date: 1995-03-28
Filing date: 1996-03-27
Publication date: 1996-10-03
Also published as: AU5002196A

Abstract

Amino amide derivatives of general formula (I), wherein R1 is hydrogen or C¿1-3?-alkyl, optionally substituted with hydroxy, R?2¿ is hydrogen, straight or branched C¿1-6?-alkyl, or straight or branched C1-6-alkyl, mono-, di- or trisubstituted in any position with hydroxy, or R?1 and R2¿ forms a C¿4-6?-cycloalkyl-group, optionally mono-, di-, or trisubstituted in any position with hydroxy, R?3¿ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl, -R8-(C=O)-R?4 or -R8-(CR5R6)-R4¿, wherein R8 is methano or ethano, R4 is C¿1-20?-alkyl, optionally substituted in any position with oxo, hydroxy, methyl or ethyl, R?5 and R6¿ are hydrogen or hydroxy, R7 is hydrogen or hydroxy, R9 is methyl, ethyl, vinyl, iso-propyl, allyl, -R13-(C=O)-R?10 or -R13-(CR11R12)-R10¿, wherein R13 is methano or ethano, R10 is C¿1-20?-alkyl, optionally substituted in any position with oxo, hydroxy, methyl or ethyl, R?11 and R12¿ are hydrogen or hydroxy, or pharmaceutically acceptable salts thereof are useful for treating ailments related to the immune system.

Description

Immunosuporessive Agents

The present invention relates to σ-amino amide derivatives which are useful for treating ailments related to the immune system. In particular, the present invention involves suppression of an immune response in a patient in need of such suppression. Immunosuppression is desired for patients having certain diseases or medical procedures, including trans¬ plant graft versus host disease, autoimmune disease and inflammatory skin diseases. Methods for preparing such immunosuppressive com- pounds and pharmaceutical compositions containing them are disclosed.

Despite the number of immunosuppressive drugs being used, there is still a medical need for new immunosuppressive agents because existing therapies in many cases are inadequate or associated with severe side- effects.

Several conditions exist in which immune suppression is warranted. Allogenic transplantation if untreated results in immunological rejection of the graft. Autoimmune diseases are a group of chronic diseases with diverse target organs, but with the common denominator that the immune system reacts in a manner that induces temporary or permanent damage to the target organ. Inasmuch as the immune system is centrally involved in the pathogenesis of the diseases, the immune system is an attractive target for pharmacological intervention in these diseases.

Current therapies for autoimmune diseases are comprised of therapies that are more or less general for all autoimmune diseases, aimed at the immunological processes or the following inflammatory cascade, and therapies that are specific for a particular disease. Often a combination of disease-specific and -general treatments are supplementary to each other. Examples of therapies that are disease-specific are bronchodilators for asthma, surgical removal of the synovium in rheumatoid arthritis, and insulin for type I diabetes. The therapies for autoimmune diseases in general are nonsteroidal antiinflammatory drugs (NSAID) aimed at the inflammatory cascade (Azathioprine, Methotrexate, Cyclophosphamide) that, among other tissues, inhibits proliferation of cells of the immune system; immune suppressants, including so-called disease-modifying drugs (Chloroquine, Gold, D-Penicillamin); Glucocorticosteroids, and specific immune suppressants (Cyclosporin A, Tacrolimus (FK 506) and Rapamycin). The NSAIDs have no effect on the cause of the underlying diseases, and often is used only to alleviate pain. The cytotoxic therapies are associated with severe side-effects, and are thus not attractive for treating non-malignant diseases. The disease modifying drugs often fail to completely control the diseases, and are associated with potentially severe side-effects, such as retinopathy, thrombo- and granulocytopenia. Prolonged use of Glucocorticosteroids may lead to a Cushing-like sγn- drome. To date the most promising agent for general immune sup¬ pression, Cyclosporin A, unfortunately also has side-effects that make it less attractive for long time treatment of autoimmune diseases. Among other side-effects of Cyclosporin A, one of the most serious is interstitial fibrosis of the kidneys, which can lead to kidney failure. Tacrolimus (FK 506) and Rapamycin have not been used extensively clinically yet, but have the same receptor as Cyclosporin A, and is thus thought also to have the interstitial fibrosis side-effects, too.

Thus despite the number of immunosuppressive drugs being used, there is still a substantial unmet medical need for novel immunosuppressive agents because existing therapies in many cases are inadequate or associated with severe side-effects. It has now been found that inhibition of the enzyme Serine palmitoyl transferase leads to inhibition of the proliferation of mononulear cells in response to various stimuli and thus to an immunesuppressive activity. Serine palmitoyl transferase inhibitors can be used therapeutically in any medical condition where systemic or local immune suppression is clinical¬ ly warranted. Specifically this includes but is not limited to immune suppression in connection with transplantation of bone marrow or other organs and graft versus host disease, autoimmune diseases such as rheumatoid arthritis, systemic sclerosis, Sjόgrens syndrom, inflammatory bowel disease, and inflammatory skin diseases including psoriasis, atopic dermatitis, and contact dermatitis. Also included are diseases of obscure pathogenesis with involvement of the immune system such as Sarcoidosis and Wegener's gramelomatosis. In addition lymphomas and leukemias may be inhibited by serine palmitoyl transferase inhibitors, inasmuch as the proliferating cells in these diseases usually are lymphocytes.

Compounds inhibiting the enzyme serine palmitoyl transferase are found to be active as immunosuppressants.

More specifically the present invention relates to amino amide derivatives of the general formula (I):

wherein R¹ is hydrogen or C*,.₃-alkyl, optionally substituted with hydroxy,

R² is hydrogen, straight or branched C*,._β-alkyl, or straight or branched

C_1-β-alkyl, mono-, di- or tri-substituted in any position with hydroxy, or R¹ and R² forms a

optionally mono-, di or tri- substituted in any position with hydroxy,

R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl,

-R^β-(C = O)-R⁴ or -R⁸-(CR⁵R^β)-R\ wherein

R⁸ is methano or ethano,

R⁴ is C,.₂₀-alkyl, optionally substituted in any position with oxo, hydroxy, methyl or ethyl,

R⁵ and R^β are hydrogen or hydroxy,

R⁷ is hydrogen or hydroxy,

R⁹ is methyl, ethyl, vinyl, iso-propyl, allyl, -R¹³-(C = O)-R¹⁰ or -R¹³-(CR ^'

R ²)-R¹⁰, wherein R¹³ is methano or ethano,

R¹⁰ is C,.₂₀-alkyl, optionally substituted in any position with oxo, hydroxy, methyl or ethyl,

R¹¹ and R¹² are hydrogen or hydroxy, or pharmaceutically acceptable salts thereof.

Physiologically and pharmaceutically acceptable salts of the compounds of the invention include acid addition salts formed with inorganic or organic acids, for example acetates, hydrochlorides, hydrobromides, sulphates, nitrates, oxalates, phosphates, tartrates, citrates, fumarates, maleates, succinates, and sulphonates, e.g., mesylates. If desirable, selected salts may be subjected to further purification by recrystallization.

The invention includes within its scope all optical isomers of compounds of the general formula I and their mixtures including racemic mixtures thereof. 381 PCIYDK96/00124

- 5 -

Preferred compounds of the invention are compounds of the following formulas:

^"OH

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either

-R⁸-(C = O)-R\ wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR⁵R⁶)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl,

R⁵ is hydrogen or hydroxy and

R^β is hydrogen or hydroxy,

b)

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either -R⁸-(C = O)-R⁴, wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR⁵R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl,

R⁵ is hydrogen or hydroxy and R⁶ is hydrogen or hydroxy,

c)

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either

R^s is hydrogen or hydroxy and R^β is hydrogen or hydroxy,

d)

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either

-R⁸-(C = O)-R⁴, wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR⁵R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octγl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl,

R⁵ is hydrogen or hydroxy and

R^β is hydrogen or hydroxy,

e)

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either -R⁸-(C = O)-R⁴, wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR⁵R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl, R⁵ is hydrogen or hydroxy and

R^β is hydrogen or hydroxy,

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either

-R⁸-(C = O)-R\ wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-{CR⁵R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl,

R⁵ is hydrogen or hydroxy and

R^β is hydrogen or hydroxy, g)

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either

-R⁸-(C = O)-R⁴, wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR⁵R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl,

R⁵ is hydrogen or hydroxy and

R^β is hydrogen or hydroxy,

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either

-R⁸-(C = O)-R⁴, wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR⁵R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl. hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl,

R⁵ is hydrogen or hydroxy and

R^β is hydrogen or hydroxy,

i)

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either -R⁸-(C = O)-R⁴, wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR⁵R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl, R⁵ is hydrogen or hydroxy and R^β is hydrogen or hydroxy, j)

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either

-R⁸-(C = O)-R\ wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR⁵R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl,

R⁵ is hydrogen or hydroxy and

R^β is hydrogen or hydroxy,

k)

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either

R⁵ is hydrogen or hydroxy and

R^β is hydrogen or hydroxy,

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either -R⁸-(C = O)-R⁴, wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR⁵R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl, R⁵ is hydrogen or hydroxy and R^β is hydrogen or hydroxy, m)

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either -R⁸-(C = O)-R⁴, wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR⁵R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl, R⁵ is hydrogen or hydroxy and R^β is hydrogen or hydroxy,

n)

wherein R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl or either

-R⁸-(C = O)-R⁴, wherein R⁸ is methano or ethano and R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl or R³ is -R⁸-(CR R^β)-R⁴ wherein R⁸ is methano or ethano, R⁴ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexa-decyl, heptadecyl, octadecyl, nonadecyl or icosyl,

R⁵ is hydrogen or hydroxy and R^β is hydrogen or hydroxy, or pharmaceutically acceptable salts thereof.

In another aspect the invention relates to a compound of the general formula (I) or a pharmaceutically acceptable acid addition salt thereof for use as a therapeutically acceptable substance, preferably for use as a therapeutically acceptable substance in the treatment of ailments related to the immune system.

Furthermore, the invention also relates to the use of the inventive com¬ pounds of formula (I) as medicaments useful for treating ailments related to the immune system such as transplantation of bone marrow or other organs and graft versus host disease, autoimmune diseases such as rheumatoid arthritis, systemic sclerosis, Sjόgrens syndrom, inflammatory bowel disease, and inflammatory skin diseases including psoriasis, atopic dermatitis, and contact dermatitis.

In another aspect the invention relates to l-cycloserine, in particular (R)- 4-amino-3-isoxazolidinone, and to enactin-derivatives and neoenactin- derivatives as described in Yamamoto et al; J. of Antibiotics, vol. 43, 1012, 1990, in particular the structures EN-la, EN-lb*,, EN-lb₂, EN-IVa, EN-IVb, EN-Va, EN-Vb, EN-VIa, NE-NL-,, NE-NL₂ and EN-Vlb of Fig. 1 , p.

1012, for use as therapeutically acceptable substances, preferably for use as therapeutically acceptable substances in the treatment of ailments related to the immune system.

Furthermore, the invention also relates to the use of l-cycloserine , neoenactin-derivatives and enactin-derivatives as medicaments useful for treating ailments related to the immune system such as transplantation of bone marrow or other organs and graft versus host disease, auto¬ immune diseases such as rheumatoid arthritis, systemic sclerosis, Sjδgrens syndrom, inflammatory bowel disease, and inflammatory skin diseases including psoriasis, atopic dermatitis, and contact dermatitis.

In yet another aspect, the invention relates to a method of preparing compounds of formula I.

A. Procedure for preparation of componds of formula la:

The procedure involves the following 3 steps:

1 . An σ-amino acid having proper protecting groups is coupled to an O-protected hydroxylamine.

2. The resultant O-protected-hydroxamate is N'-alkylated.

3. Removal of protecting groups by standard reactions yields the claimed compound.

1 . More specifically the σ-amino acid is preferably purchased from a commercial source, having proper protecting groups and an activated carbonyl group.

Alternatively (especially for unnatural amino acids), the σ-amino acid is synthesized by standard procedures or minor modifica¬ tions thereof.

Functional groups such as NH₂, OH and SH are protected with standard reagents, normally used in peptide synthesis.

The carboxylic acid is activated with standard reagents used in peptide synthesis.

Eg. forming N-Hydroxysuccinimide or O-Nitro-phenyl esters, which eventually will enable coupling of the carbonyl function to a O-protected hydroxylamine.

Alternatively, the coupling is carried out directly using reagents such as DCC (1 ,3 dicyclohexylcarbodiimide) or other standard procedures normally applied in peptide synthesis.

The O-protected hydroxylamine should preferably be O-Benzyl- hydroxylamine.

2. The resultant hydroxamate is alkylated using a reactive electrophilic reagent of the desired composition.

The reactive electrophilic group can be a monohalogenated alkyl such as Br-CH₂-R.

The reaction can be carried out in acetone\K₂CO₃ using Kl as catalyst.

R can be a broad defined composition with suitable protection of possible functional groups.

Br can be introduced by standard manipulation of functionalities.

Another reactive electrophilic reagent can be vinyl ketones of the general composition H₂C = CH-CO-R. The reaction could be carried out in eg. refluxing benzene or dioxane using eg. Potassium ferf-butoxide as catalyst. R can be a broad defined composition with suitable protection of possible functional groups.

H₂C = CH-CO-R can be prepared from eg. HOOC-R through 2 steps:

1. HOOC-R to CICO-R using eg. oxalyl chloride.

2. CICO-R to H₂C = CH-CO-R using a palladium-catalyzed cross- coupling of vinylstannanes with the acid chloride. (REF: Soder- quist, J.A. et al. Tetrahedron Lett. 1983, 24, 2361 .).

The introduced alkyl moiety can be of the type: -CH₂-CH₂-CO-R.

The ketone functionality could subsequently be reduced using eg. NaBH₄ to generate a mixture of the corresponding R and S hydroxy functionality.

3. Protecting groups are removed from the σ-amino acid moiety, the hydroxylamine moiety and the alkyi moiety by standard pro¬ cedures.

The preferred O-benzyl group from the hydroxamic acid is removed eg. by stirring in an ethanol solution containing a pal¬ ladium on activated charcoal catalyst under an atmosphere of hydrogen.

B. Procedure for preparation of compounds of formula lb:

The procedure involves the following 3 main steps: 1 . A desired hydroxylamine derivative is prepared (NH₂-O-R).

2. An σ-amino acid carrying proper protecting groups is coupled to the hydroxylamine-derivative (NH₂-O-R).

1 . More specifically, a derivative of hydroxylamine having suitable protection of the aminogroup (Prot-NH-OH) is purchased from a commercial source or prepared by standard procedures.

The free hydroxy group is subsequently alkylated using a reactive electrophilic reagent of the desired composition.

The reactive electrophilic group could be monohalogenated alkyl such as Br-CH₂-R.

The reaction could be carried out in acetone\K₂CO₃ using Kl as catalyst.

R could be a broad defined composition with suitable protection of possible functional groups.

Br could be introduced by standard manipulation of functionalities.

Another reactive electrophilic reagent could be vinyl ketons of the general composition H₂C = CH-CO-R.

The reaction could be carried out in eg. refluxing benzene or dioxane using eg. Potassium ferf-butoxide as catalyst.

H₂C = CH-CO-R could be prepared from eg. HOOC-R through 2 steps:

1 . HOOC-R to CICO-R using eg. oxalyl chloride.

2. CICO-R to H₂C = CH-CO-R using a palladium-catalyzed cross- coupling of vinylstannanes with the acid chloride. (REF: So- derquist, J.A. et al. Tetrahedron Lett. 1983, 24, 2361 .).

The introduced alkyl moiety would be of the type: -CH₂-CH₂-

COR.

Finally the protecting group is removed from the amino group yielding: H₂N-O-R or salts thereof.

2. The σ-amino acid is preferably purchased from an commercial source carrying proper protecting groups and an activated carbo- nylgroup.

Alternatively (especially for unnatural amino acids) the σ-amino acid is synthesized by standard procedures or minor modifica¬ tions thereof.

The carboxylic acid is activated with standard reagents used in peptide synthesis. Eg. forming N-Hydroxysuccinimide or O-Nitro-phenyl esters, which eventually will enable coupling of the carbonyl function to a hydroxylamin derivative (NH₂-O-R).

Alternatively the coupling is carried out directly using reagents such as DCC (1 ,3 dicyclohexylcarbodiimide) or other standard procedures normally applied in peptide synthesis.

3. Protecting groups are removed from the σ-amino acid moiety and the alkyl moiety by standard methods.

Inhibition of the enzyme Serine Palmitoyl Transferase and an in vitro test for immunosuppressive activity are determined as follows:

Methods

Isolation of mononuclear cells (MNC).

Peripheral venous blood was drawn (using 1 U/ml heparin as an anticoagulant) from normal healthy adult volunteers tested negative for HIV and Hepatitis B. After dilution 1 : 1 with Phosphate buffered isotonic saline (PBS) pH 7.4 the blood was layered on Ficoll-Hypaque^® (Pharma¬ cia, Discataway, NJ) and centrifuged at 300xg for 35 minutes. The interphase containing the MNC was removed, and the cells washed three times in PBS supplemented by 2% (v/v) fetal bovine serum (FBS) (GIBCO, Grand Island, NY). The MNC were resuspended in Dulbecco's

Modified Eagle's Medium DMEM supplemented with 10% (v/v) FBS, antibiotics, and 2 mM l-Glutamine, which was then used as medium for the described experiments.

Test Substances

Test substance stocks were dissolved in methanol as follows: Myriocin (1 mg/ml), Compound FWR6107 (100 g/ml), Dihydrosphingosine (Calbiochem, La Jolla, CA); (10 mg/ml) and stored at -20°C. I-Cyclose- rine (SIGMA, St. Louis, MO) was prepared at 0.1 M in PBS.

Mitogens Phytohemagglutinin (PHA) SIGMA, St. Louis, MO) and Staphy- lococcal Enterotoxin B (SEB; SIGMA, St. Louis, MO) were dissolved at 1 mg/ml in PBS. lonomycin (SIGMA, St. Louis, MO) was used at 1.0 nM in ethanol and Phorbol 12 Myristate 13 Acetate (PMA) SIGMA, St. Louis, MO) was used at 10 //g/ml in ethanol.

Proliferation assay

One hundred thousand MNC were seeded per well in 96-well U-botto- med microtiter wells. The test substances were added to the wells at varying concentrations. The dilutions of the test substances were made in medium containing corresponding amounts of stock solvent to ensure that the final methanol concentration was the same in all wells, including the control wells without test substance. The mitogen PHA or SEB was added to a final concentration of 1 μg/ml; lonomycin to 100nM; and PMA to 3 g/ml. Final volume was 200 μ\ in all wells.

The plates were incubated at 37°C, 5% CO2, 100% relative humidity for four days. Sixteen hours before harvest 0.5 μC\ 3H-thymidine, specific activity 25 Ci/mmol (Amersham, Arlington Heights, ILL), was added to each well. The cells were harvested onto filter mats using a

Skatron cell harvester and activity incorporated in the cells measured by liquid scintillation. The average ± standard deviation of triplicate deter¬ minations were calculated, as described in the Figures.

Results

Myriocin inhibited proliferation of mononuclear cells in response to PHA, and this inhibitory effect was attenuated by Dihydrosphingosine.

Myriocin inhibited the proliferative response of MNC to PHA (Fig. 1 , dotted line, squares) to about half of the control. At 2.5 pg/ml the inhibition was approximately 50% (Fig.1 ).

The inhibitory activity of myriocin towards MNC proliferation may therefore be due to inadequate cellular levels of sphingolipids, which are the end product of sphinoglipid de novo synthesis. An intermediary of that pathway, Dihydrosphingosine, can attenuate the inhibitory activity of myriocin. When 250 ng/ml dihydrosphingosine was added prior to the addition of myriocin to the culture, the inhibition was attenuated to approximately 25% (Fig. 1 , line, diamonds). These data indicate, that the immuno-suppressive action of myriocin is mediated by inhibition of sphingolipid synthesis. Myriocin also inhibited the proliferation of a mixed lymphocyte reaction (data not shown), as well as MNC stimulated by 100 nM lonomycin and 3 g/ml PMA (Fig. 2), demonstrating that the observed inhibition by myriocin is not due to interference of myriocin with the PHA.

Compound FWR6107 inhibited proliferation of MNC. Compound FWR6107 dose dependently inhibited the proliferative response of MNC to 1 .0 μg/ml PHA (Fig. 3). The IC50 of three indepen¬ dent experiments was 131 ± 33 nM (Average ± SD). When the T cell stimulant PHA was incubated with the MNC for one hour before addition of Compound FWR6107, Compound FWR6107 still inhibited the prolife¬ ration of MNC, although with a larger IC50 ( = 400 nM) . Also, when SEB (Fig. 4) or a combination of lonomycin and PMA (Fig. 5) was used as T cell stimulus, Compound FWR6107 inhibited proliferation of MNC, demonstrating that the inhibition is not caused by a specific interaction between PHA and the Compound FWR6107. Dihydrosphingosine attenuates the inhibition of MNC proliferation by Compound FWR6107.

It has been found that Compound FWR6107 inhibits the activity of the enzyme Serine Palmitoyl Transferase. When Dihydrosphingosine (DHS) was added to the MNC, it dose-dependently attenuated the inhibitory activity of Compound FWR6107, from the approximately 60% inhibition without DHS to 39% at the highest non-toxic dose of DHS (Fig. 6). This corresponds to decrease of (0.60-0.39) * 100/0.60 = 35% of the Com- pound FWR6107 inhibition. The inhibition is calculated as the cpm from

MNC + PHA + Compound FWR6107 at a given concentration of DHS, divided by the cpm of MNC + PHA at the same concentration of DHS. The concentrations of DHS were not increased further due to toxicity of the DHS.

l-Cycloserine inhibited proliferation of MNC in response to PHA. I-Cyclo- serine, reported to be an inhibitor of serine palmitoyl transferase, inhibited proliferation of MNC in response to PHA (Fig. 7).

The compounds of the invention, together with a conventional adjuvant, carrier, or diluent, and if desired a pharmaceutically acceptable acid addi¬ tion salt thereof, may be placed into the form of pharmaceutical compo¬ sitions and unit dosages thereof, and in such form may be employed as solids, such as tablets or filled capsules, or liquids, such as solutions, suspensions, emulsions, elixirs, or capsules filled with the same, all for oral use, in the form of suppositories for rectal administration; or in the form of sterile injectable solutions for parenteral (including subcutaneous) use. The compounds of the invention may be formulated in creams or ointments for topical administration on skin and mucous membranes including the mouth. The compounds of the invention may also be formulated as liquid for topical application preferably in the conjunctiva. Such pharmaceutical compositions and unit dosage forms thereof may comprise conventional ingredients in conventional proportions, with or without additional active compounds or principles, and such unit dosage forms may contain any suitable effective amount of the active ingredient commensurate with the intended daily dosage range to be employed. Tablets containing one (1 ) milligram of active ingredient or, more broad¬ ly, one (1 ) to thirty (30) milligrams, per tablet, are accordingly suitable representative unit dosage forms.

The compounds of this invention can thus be used for the formulation of pharmaceutical preparations, e.g. for oral, topical and parenteral admini¬ stration to mammals including humans, in accordance with conventional methods of galenic pharmacy.

Conventional excipients are such pharmaceutically acceptable organic or inorganic carrier substances suitable for parenteral or oral application which do not deleteriously react with the active compound.

Examples of such carriers are water, salt solutions, alcohols, polyethy¬ lene glycols, polyhydroxyethoxylated castor oil, gelatine, lactose, amylose, magnesium stearate, talc, silicic acid, fatty acid monoglycerides and diglycerides, pentaerythritol fatty acid jesters, hydroxymethylcellu- lose and polyvinylpyrrolidone.

The pharmaceutical preparations can be sterilized and mixed, if desired, with auxiliary agents, such as lubricants, preservatives, stabilizers, wetting agents, emulsifiers, salt for influencing osmotic pressure, buffers and/or coloring substances and the like, which do not deleteriously react with the active compounds.

For parenteral application, particularly suitable are injectable solutions or suspensions, preferably aqueous solutions with the active compound dissolved in polyhydroxylated castor oil. The compounds described in the present application may also be formu¬ lated to be used topically on skin or mucous membranes including the mouth. The preferred concentration of the compounds is from 0.00001 % to 1 % (w/w), a particularly preferred concentration range from 0.001 % to 0.5% and a most preferred concentration range of

0.01 % to 0.5% in a vehicle of ointments, salves, gels, emulsions or the like formulated by a person skilled in the art of pharmaceutical formula¬ tion. The agent may be applied topically from once to several times daily. Optimal dosage regimen may be investigated in a mouse model of contact dermatitis using topical sensitization with haptens such as DNCB and subsequent challenge.

Ampoules are convenient unit dosage forms.

For oral application, particularly suitable are tablets, dragees, or capsules having talc and/or a carbohydrate carrier or binder or the like, the carrier preferably being lactose and/or corn starch and/or potato starch. A syrup, elixir or like can be used when a sweetened vehicle can be employed. Generally, as to broader ranges, the compound of the inven- tion is dispensed in unit dosage form comprising 0.05-100 mg in a pharmaceutically acceptable carrier per unit dosage.

A typical tablet which may be prepared by conventional tabletting tech¬ niques contains:

Active compound 1 .0 mg

Lactosum 67.8 mg Ph.Eur.

Avicel^® 31 .4 mg

Amberlite^® IRP 88 1.0 mg Magnesii stearas 0.25 mg Ph.Eur. It is described in this application that inhibition of the enzyme Serine palmitoyl transferase leads to inhibition of the proliferation of mononuclear cells in response to various stimuli and thus an immune suppressive activity. Because the target of the serine palmitoyl transferase inhibitors is different from any of the immunosuppressive agents presently used, serine palmitoyl transferase inhibitors may present a different side-effect profile that may be more acceptable than the severe side-effects associated with existing drugs.

The doses of serine palmitoyl transferase inhibitors effective systemically in vivo will depend on bioavailability of the specific compound. Cyclosporin A is a compound that inhibits T-lymphocyte activation after binding to immunophilins in cells.

Immunophylins are present in many cell types, so even though the inhibition of T-cell activation by Cyclosporin A is fairly specific, it is distributed to many other cell types. Cyclosporin A is lipophilic. Serine palmitoyl transferase is present in most cells like the receptor for Cyclosporin A cyclophylin and serine palmitoyl transferase inhibitors are expected to be lipophilic like Cyclosporin A. Therefore, the in vitro - jn vivo correlate may be similar for Cyclosporin A and serine palmitoyl transferase inhibitors. Preferred clinically used doses of the claimed compounds would be from 0.0001 mg/kg/day to 50 mg/kg/day. More particularly preferred dose range is 0.001 mg/kg/day to 25 mg/kg/day and most particularly preferred dose range is 0.01 mg/ kg/day to 10 mg/kg/day. Should the in vitro activity of the claimed compounds be more potent than FWR6107, correspondingly lower doses may be required clinically. The frequency of compound dosing may be from 3 times a day to once weekly, depending on the pharmacological pro- perties of the specific compound and the formulation used.

Several animal models can be used to demonstrate efficacy and to investigate optimal dosage regimens. For transplantation, one of the most commonly used animal models is rejection of skin allotransplants in mice. For graft-versus-host disease, a commonly used model is injection intravenously of allogenic mononuclear cells in mice sublethally irradiated with gamma-rays. For many of the autoimmune diseases, specific animal models exist: BB-rat and NOD mice for type I diabetes, Experimental allergicencephalitis for Multiple Sclerosis, Adjuvant Arthritis in Lewis rats, and Collagen induced Arthritis in rats or mice for Rheumatoid Arthritis; NZB mice and MRL-lpr/lpr mice for lupus erythematosus; and the like.

The anticipated clinical dose regimen of Serine palmitoyl transferase inhibitors will depend on the specific condition being treated. In conjunc¬ tion with transplantation, serine palmitoyl transferase inhibitors may be administered at doses up to 50 mg/kg/day from 1 -2 days prior to the transplantation until 2 weeks after the transplantation, the period in which the initial priming of the host immune system to the transplant antigens is at its peak. Later the doses may be decreased to a chronic use dose level comparable to that used in the autoimmune diseases described below.

During acute exacerbations of autoimmune diseases, in particular in the diseases of relapsing nature such as Multiple Sclerosis and Systemic Lupus Erythematosus, the doses of serine palmitoyl transferase inhibitors given will be up to 50 mg/kg/day, while the dose given for maintenance therapy may be at the lower end of the anticipated dose range 0.001 mg/kg/day - 25 mg/kg/day. The particular doses given in the individual patient will depend upon clinical (e.g. neurological, joint swelling) and paraclinical (e.g. acute phase reactants in serum, kidney function tests) parameters and will vary with time in the same patient according to the clinical course of the disease. The doses given will furthermore depend on the age, weight, sex and general health of the patient. Sphingolipids are one of the major constituents of the central nervous system (CNS). Thus CNS related side-effects such as headache, tremor, convulsions may arise from use of serine palmitoyl transferase inhibitors, an in particular with chronic use. Thus, molecular modifications of the compound claimed in this application, that are aimed at decreasing the availability of the compound to the CNS may diminish these anticipated side-effects.

The following non-limitating examples illustrate the invention.

EXAMPLE 1

Synthesis of FWR6107 (four steps):

1. step: Benzyl-N-{fβ/ -Butyloxycarbonyl)-O-benzyl-L-serinehydroxamate

(C_βH₅-CH₂-O-CH₂-CH(NH-CO-O-C(CH₃)₃)CO-NH-O-CH₂-C_βH₅, Structure 1 a).

900 mg of N-terf-butyloxycarbonyl-O-Benzyl-L-serine N-hydroxy-succini- mide ester (SIGMA, St. Louis, MO) is dissolved in a mixture of 8 ml dry acetonitrile and 0,80 ml dry pyridine.

Excess O-Benzyl-hydroxylamine hydrochloride (SIGMA, st. Louis, MO) is suspended in the solution. After 3 hours stirring at room temperature, unconsumed O-Benzyl- hydroxylamine is removed by filtration and the solvent is removed by evaporation.

To the crude product is added 10 ml of ethylacetate and 5 ml of 0,5 M citric acid. The resulting aqueous layer is discarded.

The ethylacetate solution is extracted with:

10 ml of 0,5 M citric acid

5 ml of 0,5 M citric acid 10 ml of 0,5 M NaHCO₃ 10 ml of 0,5 M NaHCO₃ 10 ml of water.

Following each extraction the aqueous layer is discarded.

The ethylacetate solution is dried over Na₂SO₄ and addition of heptane yields the title compound as crystals (colourless needles) 879 mg (95%) TLC (structure 1 a): Merck, Kieselgel 60, F₂₅₄, thickness = 0,2 mm, eluent: 25 % ethylacetate/heptane, Rf = 0,20).

'H (CDCI₃): 9.02 (1 H,s(br)), 7.20-7.30 (10H,m,Ph), 5.34 (1 H,s(br)), 4.90 (2H,s,O-CH₂Ph), 4.49 (2H,AB,O-CH₂Ph), 4.25 (1 H,s(br)), 3.81 (1 H,dd,J = 4.3 and 9.2 Hz), 3.52 (1 H,t(br)) 1 .43 (9H,s,(CH₃)₃C)).

¹³C (CDCI₃): 1 68.2 (s, N-CO), 1 55.4 (s, O-CO-N), 1 37.1 (s), 1 35.0 (s), 1 29.2 (d,2C), 1 28.7 (d), 128.5 (d,2C), 128.4 (d,2C), 1 27.9 (d), 1 27.7 (d,2C), 80.4 (s,(CH₃)₃C-O), 78.3 (t,CH₂-O), 73.4 (t,CH₂-O), 69.4 (t,CH₂- O), 52.2 (d,σ-CH), 28.3 (3C,(CH₃)₃-C). 2. Step: Benzyl-(N-(tert-Butyloxycarbonyl)-O-benzyl)-N'-pentadecyl-L- serine Hydroxamate (C_βH₅-CH₂-O-CH₂-CH(NH-CO-O-C(CH₃)₃)CO-N(O-CH₂- C_βH₅)(CH₂)₁₄-CH₃, structure 1 b).

142 mg of Benzyl-N-(ferf-Butyloxycarbonyl)-O-benzyl-L-serine hydro¬ xamate (structure 1 a) is dissolved in a 2,0 ml acetone suspension of 13 mg Kl and 139 mg K₂CO₃.

0,25 ml of pentadecyl bromide (Aldrich), is added and the solution is kept at 55 °C for 24 hrs. 0,125 ml of pentadecyl bromide is added and the solution is kept at 55 °C for another 24 hrs.

The reaction mixture is filtered and the solvent removed by evaporation under reduced pressure.

The crude residue is chromatographed on silica gel (10 % ethylacetate/ Heptane - 20 % ethylacetate/heptane) yielding 107 mg (50 %) of the titled compound as a clear oil.

TLC (structure 1 b): Merck, Kieselgel 60, F₂₅₄, thickness = 0,2 mm, eluent: 25 % ethylacetate/heptane, Rf = 0,47). 'H (CDCI₃): 7.40 (5H,s,Ph), 7.28 (5H,m,Ph), 5.49 (1 H,d, = 8.6 Hz,NH), 4.99 (1 H,σ-CH), 4.91 (2H,s,O-CH₂Ph), 4.51 (2H,AB,O-CH₂Ph), 3.93 and 3.40 (1 H each,m,CH₂N) 3.71 (2H,m,CH₂-OBz), 1 .63 (2H,m, CH₂CH₂N), 1 .47 (9H,s,(CH₃)₃C), 1.25-1.35 (24H,m, CH₃(CH₂)₁₂CH₂), 0.90 (3H,t,J= 6.6 Hz, CH₃(CH₂)₁₄)

¹³C (CDCI₃): 170.82 (s,CO-N), 155.5 (s, O-CO-N), 137.8 (s), 134.2 (s), 129.2 (d), 128.9 (d), 128.7 (d,2C), 128.3 (d,2C), 127.6 (d,2 x 2C), 79.6 (s,(CH₃)₃C-O), 76.7 (t,CH₂-O), 73.0 (t,CH₂-O), 69.9 (t,CH₂-O), 51.2 (d,σ-CH), 45.6 (t,CH₂-N), 31.9, 29.7 (4C), 29.7, 29.6, 29.5, 29.4,

29.2, 26.7, 26.6, 22.7 (t's,CH₃(CH₂)₁₃), 28.4 (3C,(CH₃)₃-C), 14.1 (q,CH₃(CH₂)₁₄)

3. Step: Benzyl-{O-benzyl)-N'-pentadecyl-L-serine Hydroxamate (C_βH_s- CH₂-O-CH₂-CH(NH₂)CO-N(O-CH₂-C_βH₅)(CH₂)₁₄-CH₃, structure 1 c).

105 mg of Benzyl-(N-(ferf-Butyloxycarbonyl)-O-benzyl)-N'-penta-decyl-L- serine Hydroxamate (structure 1 b) is dissolved in 1 ,0 ml of a 4 to 1 mixture of chloroform (CHCI₃) and trifluoracetic acid. The mixture is left for 2 days at room temp.

The volatiles are then evaporated, affording 126 mg of a colourless oil. Which contains no unconverted structure 1 b judged by TLC.

¹H (CDCI₃): 7.1 -7.4 (12H,2xPh + NH₂), 4.82 (2H,AB-q,O-CH₂Ph) 4.54 (1 H,m,σ-CH), 4.47 (2H,AB-q,O-CH₂Ph), 3.94 and 3.30 (1 H each,ddd,CH₂N) 3.80 (2H,AB-syst,CH₂-OBz), 1.55 (2H,m, CH₂CH₂N),

1 .25-1 .35 (24H,m, CH₃(CH₂)₁₂CH₂), 0.89 (3H,t, = 6.6 Hz, CH₃(CH₂)₁₄)

¹³C (CDCI₃): 166.1 (s,CO-N), 136.5 (s), 133.3 (s), 129.4 (d), 128.2 (d,2C), 128.9 (d,2C), 128.5 (d,2C), 128.1 (d), 127.8 (d,2C), 76.9 (t,CH₂-O), 73.3 (t,CH₂-O), 66.1 (t,CH₂-O), 52.5 (d,σ-CH), 45.8 (t,CH₂-N),

31.9, 29.7 <5C), 29.6 (2C), 29.4, 29.4, 29.2, 26.5, 22.7 (t's,CH₃(CH₂)₁₃), 14.1 (q,CH₃(CH₂)₁₄)

4. Step: N'-pentadecyl-L-serine Hydroxamic acid Visulfate salt (HO-CH₂- CH(NH₂)CO-N(OH)(CH₂)₁₄-CH₃, FWR6107).

126 mg Benzyl-(O-benzyl)-N'-pentadecyl-ι-serine Hydroxamate (structure 1c) is dissolved in 10 ml of ethanol and added 0,2 g 10% Pd/C (FLUKA). The reaction mixture is stirred at room temperature under a hydrogen atmosphere (1 bar) for 2 hrs.

The catalyst is removed by filtration and the solvent evaporated to give 80 mg of a clear oil. The titled compound FWR6107 crystallized as needles from CHCI₃ and was harvested by filtration. This saltform of FWR6107 is still to be determined, but is most likely the zwitter-ion or the triflouracetic acid salt.

PDMS: Calcd.: MH⁺ = 331 ,5, Found: MH⁺ = 331 ,3 +/- 1.

IR (KBr powder): 3140, 2920, 2840, 1690, 1650, 1605, 1460, 1230,

1 175, 1 120, 805, 720 cm ¹.

¹H (CD₃OD): 4.41 (1 ,όd,J= 7.0 and 3.7 Hzσ,-CH), 4.02/3.79

(1 H/1 H,dd/dd, J = 3.7 and 1 1.5 Hz/ = 1 1.5 and 7.0 Hz),CH₂OH) 3.61 (2H,dd, J= 7.6 and 6.7 Hz, CH₂N), 1.64 (2H,m, CH₂CH₂N), 1 .25-1.35 (24H,m, CH₃(CH₂)₁₂CH₂), 0.90 (3H,t,J = 6.6 Hz, CH₃(CH₂)₁₄)

¹³C (CD₃OD): 167.5 (s,CO-N), 60.4 (t,CH₂-O), 55.1 (d,σ-CH), 49.6

(t,CH₂-N), 33.1 , 30.8 (5C), 30.7, 30.6, 30.5, 30.4, 27.6, 27.4, 23.7, (t's,CH₃(CH₂)₁₃), 28.4 (3C,(CH₃)₃-C), 14.4 (q,CH₃(CH₂)₁₄)

The crystals are resuspended in the CHCI₃ filtrate and extracted with 0,5 M NaHCO₃ (pH = 8) added a few % ethanol.

The CHCI₃ extract is filtered (1 1 ml filtrate) and 1 1 ml 0,2 M H₂SO₄ is added while stirring.

The mixture is left overnight at 5 °C and the titled compound (FWR6107) precipitated as a fine white solid which is harvested by filtration as 33,6 mg of a waxy substance.

All biological data related to FWR6107 has been generated using this material.

The crystalline form described above and this sulfate salt displayed exactly similar retention on analytical HPLC, using a Merck Superspher 100 RP-18 4X75 mm column and a 60 to 90 w/w-% acetonitrile in water ( + 0,1 % trifluoracetic acid) gradient.

PDMS: Calcd.: MH⁺ = 331 ,5, Found: MH⁺ = 331 , 1 + /- 1.

IR (KBr powder): 3310, 3120, 2920, 2845, 1630, 1480, 1 1 15, 1080 cm^'1.

¹H (CD₃OD): 4.47 (1 H,dd, = 7.0 and 3.7 Hzσ,-CH), 4.04/3.76 (1 H/1 H,dd/dd, J = 3.5 and 1 1.6 Hz/J = 7.0 and 1 1.6 Hz,CH₂OH) 3.62

(2H,ddd, J= 13.9, 7.1 and 6.8 Hz, CH₂N), 1.64 (2H,m, CH₂CH₂N), 1.25- 1 .35 (24H,m, CH₃(CH₂)₁₂CH₂), 0.89 (3H, = 6.4 Hz, CH₃(CH₂)₁₄)

NMR spectra were recorded at 297K using a Bruker AC300 instrument operating at 300.13 and 75.47 MHz, for 'H and ¹³C, respectively.

Solvent peaks (CDCI₃: 7.27 CH) and 77.0 ( ¹³C) ppm; CD₃OD: 3.30 CH) and 49.0 (¹³C) ppm) were used as references for scaling the spectra.

IR spectra were recorded using a Perkin Elmer FTIR model 1600. PDMS data were recorded using a Bioion 20.

Claims

I_s, A compound of the general formula (I)

wherein

R¹ is hydrogen or C_1-3-alkyl, optionally substituted with hydroxy, R² is hydrogen, straight or branched C,._β-alkyl, or straight or branched

Cι._β-alkyl, mono-, di- or trisubstituted in any position with hydroxy, or R¹ and R² forms a

optionally mono-, di-or trisub¬ stituted in any position with hydroxy,

R³ is hydrogen, methyl, ethyl, vinyl, iso-propyl, allyl, -R⁸-(C = O)-R⁴ or -R⁸-(CR⁵R^β)-R\ wherein

R⁸ is methano or ethano,

R⁴ is C_1-20-alkyl, optionally substituted in any position with oxo, hydroxy, methyl or ethyl,

R⁵ and R^β are hydrogen or hydroxy, R⁷ is hydrogen or hydroxy,

R⁹ is methyl, ethyl, vinyl, iso-propyl, allyl, -R¹³-(C = O)-R¹⁰ or -R¹³-

(CR R¹²)-R¹⁰, wherein

R¹³ is methano or ethano,

R¹⁰ is C*.₂₀-alkyl, optionally substituted in any position with oxo, hydroxy, methyl or ethyl,

R ¹ and R¹² are hydrogen or hydroxy, or pharmaceutically acceptable salts thereof. 2_ A compound according to claim 1 wherein R¹ is hydrogen and R² is hydroxymethyl.

3_i A compound according to claim 1 wherein R³ is -R⁸-(CR⁵R^β)-R⁴, wherein R⁸ is ethano, R⁵ and R^β are hydrogen and R⁴ is C₁₀.₁₄-alkyl.

4j. A compound according to claim 3 wherein R is dodecyl.

5^ A compound according to any of the claims 1 , 2, 3 or 4 wherein R⁷ is hydroxy.

f A pharmaceutical composition comprising a compound according to any one of the claims 1-5 or a pharmaceutically acceptable salt thereof and a therapeutically inert excipient, carrier or diluent.

2_ A pharmaceutical composition for the treatment of a medical condition where systemic or local immune suppression is needed, which comprises a compound according to any of the claims 1 -5 or a pharma¬ ceutically acceptable salt thereof and a therapeutically inert excipient, carrier or diluent.

i Use of a compound of formula I according to claim 1 or a phar¬ maceutically acceptable salt thereof for the manufacture of a medic¬ ament for the treatment of a medical condition where systemic or local immune suppression is needed.

9_j. A method of treating ailments such as transplantation of bone marrow or other organs and graft versus host disease, autoimmune diseases such as rheumatoid arthritis, systemic sclerosis, Sjόgrens syndrom, inflammatory bowel disease, and inflammatory skin diseases including psoriasis, atopic dermatitis, and contact dermatitis in a subject in need thereof comprising administering an effective amount of a compound according to claim 1.

10. A method of treating ailments such as transplantation of bone marrow or other organs and graft versus host disease, autoimmune diseases such as rheumatoid arthritis, systemic sclerosis, Sjόgrens syndrom, inflammatory bowel disease, and inflammatory skin diseases including psoriasis, atopic dermatitis, and contact dermatitis, in a subject in need thereof comprising administering a pharmaceutical composition according to claim 7.

1 1 . A process for the manufacture of a medicament, particularly to be used in the treatment of ailments such as transplantation of bone marrow or other organs and graft versus host disease, autoimmune diseases such as rheumatoid arthritis, systemic sclerosis, Sjόgrens syndrom, inflammatory bowel disease, and inflammatory skin diseases including psoriasis, atopic dermatitis, and contact dermatitis , which process comprises bringing a compound of formula I according to claim 1 or a pharmaceutically acceptable salt thereof into a galenical dosage form.

12. Use of l-cycloserine, neoenactin-derivatives and enactin-deriva¬ tives for the manufacture of a medicament useful for treating of ailments related to the immune system.