CA2151323A1 - Process for the preparation of 2,2-dichloromalonic diesters - Google Patents
Process for the preparation of 2,2-dichloromalonic diestersInfo
- Publication number
- CA2151323A1 CA2151323A1 CA 2151323 CA2151323A CA2151323A1 CA 2151323 A1 CA2151323 A1 CA 2151323A1 CA 2151323 CA2151323 CA 2151323 CA 2151323 A CA2151323 A CA 2151323A CA 2151323 A1 CA2151323 A1 CA 2151323A1
- Authority
- CA
- Canada
- Prior art keywords
- process according
- reaction
- carboxylic acid
- carried out
- acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/30—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group
- C07C67/307—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by introduction of halogen; by substitution of halogen atoms by other halogen atoms
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A process for the preparation of 2,2-dichloromalonic diesters by reacting malonic diesters with aqueous alkali metal hypochlorite solutions or alkaline earth metal hypochlorite suspensions in the pH range 8 at low reaction temperatures is described. High yields and very pure products are obtained with this process.
Description
- HULS A~TID G~RT~T-~C~A~T 0.Z. 4849 - Patent Department -Process for the prearation of 2,2-dlchloromalonic diesters The present invention relates to a process for the preparation of 2,2-dichloromalonic diesters by reacting malonic diesters with aqueous alkali metal hypochlorite solutions or alk~ine earth metal hypochlorite suspen-sions in the pH range > 8 at low reaction temperatures.
Dialkyl dichloromalonates are used as activators in EPM/
EPDM copolymerization (German Offenlegungsschrift 23 44 267 and Canadian Patent 1 014 299) or aæ fireproof-ing agents in polycarbonates (German Offenlegungsschrift 24 60 946). They are also uæed aæ photographic developers (German Offenlegungsschrift 21 46 430) or as additives to chromium plating baths (Trans. Int. Met. Finish 1985, 34).
Examples of synthesis of 2,2-dichloromalonic diesters starting from the corresponding malonic diester are described in the literature:
Forster et al. tJ~ Chem. Soc. 97 (1910), 130] and Amriev et al. tZh. Prikl. Rhim. (Leningrad) 1985, 2504] report the chlorination of diethyl malonate with elemental chlorine at elevated temperature to give a mixture of monochloro- and, predomin~ntly, dichloromalonic ester.
Conrad et al. [Chem. Ber. 35 (1902), 1815] carried out the chlorination of malonic acid using sulphuryl chloride in addition to subsequent esterification of the dichloro-malonic acid formed. Swiss Patent 599 092 reports an analogous reaction although using thionyl chloride in acetic acid as solvent.
Other authors, æuch as Just et al., [Tetrahedron Lett.
1979, 3643], carry out the chlorination of diethyl malonate with trifluoromethanesulphonic acid chloride, Hori et al. [Chem. Abstr. 93, 95 231 h (1988)] with ' ' 215~323 - 2 - O.Z. 48~g carbon tetrachloride in the presence of tertiary organic N base~, Terpighorev et al. tZh. Org. ~hlm. 1980, 2545]
of mono-Na salts of malonic diesters with carbon tetrachloride, Yonemura et al. tBull. Chem. 80C. Jap.
1987, 809] with the Mn(III) acetate/chloride redo~
system.
Chlorinations of monochloromalonic diester are al~o reported:
Thus, monochloromalonic diester ha6 been chlorinated to the desired product by Conrad et al. tChem. Ber. 24 (1981), 2993] using elemental chlorine, by Macbeth et al.
[J. Chem. Soc. 121 (1922), 1120 and 2177] using sulphuryl chloride, and by Shevchenko et al. tZhur. Obshch. Rhim.
32 (1962), 2994] using phosphorus pentachloride.
It is common to all the processes described in the literature that the yields of the required products are usually only unsatisfactory, the dichloro derivatives being cont~min~ted with varying amounts of monochloro compounds, and that the chlorinating agents used to prepare the required products are, because of their nature or their reaction products resulting in the desired reaction, of low suitability for industrial manufacture of the desired products from the viewpoints of process technology, economics and ecology.
The object therefore was to find a process which is simple in terms of process technology, is economic and gives good yields, for the preparation of 2 r 2-dichloro-malonic diesters from the underlying malonic diesters which can be obtained conveniently.
Surprisingly, this object has been achieved by the process according to the invention in which malonic diesters of the general formula I
Dialkyl dichloromalonates are used as activators in EPM/
EPDM copolymerization (German Offenlegungsschrift 23 44 267 and Canadian Patent 1 014 299) or aæ fireproof-ing agents in polycarbonates (German Offenlegungsschrift 24 60 946). They are also uæed aæ photographic developers (German Offenlegungsschrift 21 46 430) or as additives to chromium plating baths (Trans. Int. Met. Finish 1985, 34).
Examples of synthesis of 2,2-dichloromalonic diesters starting from the corresponding malonic diester are described in the literature:
Forster et al. tJ~ Chem. Soc. 97 (1910), 130] and Amriev et al. tZh. Prikl. Rhim. (Leningrad) 1985, 2504] report the chlorination of diethyl malonate with elemental chlorine at elevated temperature to give a mixture of monochloro- and, predomin~ntly, dichloromalonic ester.
Conrad et al. [Chem. Ber. 35 (1902), 1815] carried out the chlorination of malonic acid using sulphuryl chloride in addition to subsequent esterification of the dichloro-malonic acid formed. Swiss Patent 599 092 reports an analogous reaction although using thionyl chloride in acetic acid as solvent.
Other authors, æuch as Just et al., [Tetrahedron Lett.
1979, 3643], carry out the chlorination of diethyl malonate with trifluoromethanesulphonic acid chloride, Hori et al. [Chem. Abstr. 93, 95 231 h (1988)] with ' ' 215~323 - 2 - O.Z. 48~g carbon tetrachloride in the presence of tertiary organic N base~, Terpighorev et al. tZh. Org. ~hlm. 1980, 2545]
of mono-Na salts of malonic diesters with carbon tetrachloride, Yonemura et al. tBull. Chem. 80C. Jap.
1987, 809] with the Mn(III) acetate/chloride redo~
system.
Chlorinations of monochloromalonic diester are al~o reported:
Thus, monochloromalonic diester ha6 been chlorinated to the desired product by Conrad et al. tChem. Ber. 24 (1981), 2993] using elemental chlorine, by Macbeth et al.
[J. Chem. Soc. 121 (1922), 1120 and 2177] using sulphuryl chloride, and by Shevchenko et al. tZhur. Obshch. Rhim.
32 (1962), 2994] using phosphorus pentachloride.
It is common to all the processes described in the literature that the yields of the required products are usually only unsatisfactory, the dichloro derivatives being cont~min~ted with varying amounts of monochloro compounds, and that the chlorinating agents used to prepare the required products are, because of their nature or their reaction products resulting in the desired reaction, of low suitability for industrial manufacture of the desired products from the viewpoints of process technology, economics and ecology.
The object therefore was to find a process which is simple in terms of process technology, is economic and gives good yields, for the preparation of 2 r 2-dichloro-malonic diesters from the underlying malonic diesters which can be obtained conveniently.
Surprisingly, this object has been achieved by the process according to the invention in which malonic diesters of the general formula I
- 3 - O.Z. 4849 H\ ~ CO2_ R1 H \ C02- R2 in which Rl and Rz have the meaning of straight-chain or branched Cl- to C6-alkyl, cycloalkyl and aralkyl, and the radicals Rl and R2 can be identical or different, are reacted with aqueous alkali metal hypochlorite 801ut~0n8 S or alkaline earth metal hypochlorite suspensions at pH
values 2 8 at low temperatures to give the desired products of the general formula II
a C2 - R
/C /
a co2--R2 in which Rl and R2 have the abovementioned meAnin~.
The reaction which has been found can be described, for example when sodium hypochlorite solution is used, by the following formal reaction equation:
H~ ~CC~--R
~C~ ~ 2 I`bOCI --~ 2 NqOH + ~C~
H C~--R2 a o~-- ~
It was also surprising that buffering of the sodium hydroxide solution which is liberated in the reaction by dilute mineral acids such as hydrochloric, sulphuric or phosphoric acid, or else by suitable organic acids such as formic acid, or substituted acetic and propionic acids, such as, for example, monochloro-, dichloro- or trichloroacetic acid, or aromatic carboxylic acids which can be diluted with water and optionally carry one or more inert substituents, and maintAinin~ the pH of the reaction mixture constant in the pH range 8 to 14, preferably in the pH range 8.5 to 14, and particularly 2 i S 1 3 2 3 - 4 - O.g. 4849 preferably in the range 9 to 14, leads to extremely high yields of dichloromalonic esters co~bined with estremely high product purities.
The pH range in which the desired reaction is carried out lies in a wide range. Thus, on the one hand, account should be taken of the stability of the hypochlorites used by a pH ~ 8 and, on the other hand, the pH should be re~tricted in the alkalinity of the reaction mixture to achieve optimal yields, that is to say to avoid losses of precursor and desired product as a consequence of hydro-lysis reactions; for this reason it i8 expedient for the upper limit of the reaction pH to be limited to ~ 14. The preferred pH range is 8.5 to 14.
It has furthermore been found that low reaction tempera-tures are beneficial for the yields and product puritywhich can be achieved. The temperature range is therefore expediently from 0 to 50C, and the preferred temperature range is from 2 to 25C. This temperature range ensures fast and mild reaction of the precursors used; however, it is also possible to use lower temperatures.
The described reaction can be carried out, for example, by initially introducing the hypochlorite in the form of an aqueous solution or suspension, and metering in the precursor while maintaining the pH range constant, as described above, by metering of one of the acids described above, which takes place in parallel, it also being possible to continue the acid metering in the after-reaction phase to maintain the chosen pH range.
However, a reverse procedure may also be chosen, that is to say initial introduction of the precursor and metering of the hypochlorite solution in addition to the acid metering.
It is possible and expedient in the malonic ester chlori-nation to be carried out using hypochlorites for a slight 21S1323 ~ `
_ 5 _ O.Z. 48~49 excess of hypochlorite to be used, based on the mnlonic esters used; the eXCQ88 to be U8Qd i8 not critical. In general, 2 to 20%, preferably 5 to 10%, excess of hypo-halite are used. The malonic ester/hypochlorite ratios are from 1 : 1 to 1 : 2, preferably from 1 : 1.05 to 1 :
1.2. After the end of the reaction, this hypochlorite content which is still present is decomposed in a known manner, for example by A~ g a~ueous ~odiu~ ~ulphite where appropriate.
These reactions generally result in a two-phase reaction mixture from which it is easy to remove the organic phase. In this connection, it is expedient to remove desired product which is still dissolved in the resulting aqueous phase using a suitable extractant.
Extractants which are suitably used are preferably solvents which are immiscible with water, such as halogenated hydrocarbons, aliphatic, cycloaliphatic and aromatic hydrocarbons, esters and ethers, which can easily be removed after the extraction from the desired product, for example by normal or fractional vacuum distillation.
The following examples demonstrate the range of applica-tion of the process which has been devised.
Example 1 217.8 g of aqueous sodium hypochlorite solution (content:
8.55% NaOCl equivalent to 250 mmol of NaOCl) are cooled to 5C, and the pH of the solution is adjusted to about 9.1 by adding aqueous 20% strength hydrochloric acid.
36.0 g of diethyl malonate (225 mmol) are added dropwise over the course of about 30 minutes to this cooled initial solution, maint~i n; ng the pH of the solution in the range 9.0 to 9.2 by the simultaneous metering of an aqueous 20% strength hydrochloric acid, and maint~ining the internal temperature at about 5~C by cooling.
~ 2 1 5 1 3 2 3 - - 6 - O.Z. 4849 After the metering of malonic ester is complete, reaction is allowed to continue for 10 minute~ while ~ainta~ning the pH range constant. Then excess sodium hypochlorite which is still present is decomposed by adding sodium sulphite, the organic phase is removed from the 2-phase mixture, the aqueous phase is exhaustively extracted with tert-butyl methyl ether, and the organic phase and extracts are combined.
After evaporation of this solution, the resulting residue is sub~ected to vacuum di~tillation. 50.8 g of diethyl 2,2-dichloromalonate of boiling point 95 to 96C (S hPa) are obtained, which is equivalent to a yield of 98.6% of theory; the purity of the product determined by gas chromatography is ~ 99.5%, the content of monochloro compound is ' 0.2%.
ExamPle 2 In analogy to Example 1 but using 48.6 g of diisobutyl malonate (225 mmol). The initial and reaction pH range is 12.0 to 12.2.
After analogous ~ Jl~U~ 58.0 g of diisobutyl 2,2-di-chloromalonate of boiling point 114 to 117C (5 hPa) are obtained (purity of the desired product: > 99.3%), which is equivalent to a yield of 90.4% of theory.
Example 3 In analogy to Example 1 but using 29.7 g of dimethyl malonate (225 mmol).
Analogous workup results in 39.9 g of dimethyl 2,2-di-chloromalonate of boiling point 72 to 73C (5 hPa) (purity: > 99.5~), which is equivalent to a yield of 88.2~ of theory.
- ~ = 2 1 ~ 1 3 ~ J
~- 7 - O.Z. 48~9 Exam~le 4 In analogy to Example 1 but using 42.3 g of diisG~o~yl malonate (225 mmol). The reaction i8 started at pH 13 and carried out in the range 13.0 to 13.5, with the after-reaction time being about 60 minutes.
Analogous workup results in 52.5 g of diisopropyl 2,2-di-chloromalonate of boiling point 92 to 93C (5 hPa) (purity: 2 99.5%), which is equivalent to a yield of 90.8% of theory.
ExamPle 5 In analogy to Example 4 but using 42.3 g of tert-butyl ethyl malonate (225 mmol). The reaction and after-reac-tion is carried out in the temperature range 20 to 22C.
Analogous workup results in 48.8 g of tert-butyl ethyl 2,2-dichloromalonate of boiling point 95 to 96C (5 hPa) (purity: > 98%), which is equivalent to a yield of 84.4 of theory.
Example 6 Analogous to Example 4 but using 39.2 g of tert-butyl methyl malonate (225 mmol).
Analogous workup results in 46.8 g of tert-butyl methyl 2,2-dichloromalonate of boiling point 86 to 88C (5 hPa) (purity: > 99%), which is equivalent to a yield of 85.2 of theory.
.
values 2 8 at low temperatures to give the desired products of the general formula II
a C2 - R
/C /
a co2--R2 in which Rl and R2 have the abovementioned meAnin~.
The reaction which has been found can be described, for example when sodium hypochlorite solution is used, by the following formal reaction equation:
H~ ~CC~--R
~C~ ~ 2 I`bOCI --~ 2 NqOH + ~C~
H C~--R2 a o~-- ~
It was also surprising that buffering of the sodium hydroxide solution which is liberated in the reaction by dilute mineral acids such as hydrochloric, sulphuric or phosphoric acid, or else by suitable organic acids such as formic acid, or substituted acetic and propionic acids, such as, for example, monochloro-, dichloro- or trichloroacetic acid, or aromatic carboxylic acids which can be diluted with water and optionally carry one or more inert substituents, and maintAinin~ the pH of the reaction mixture constant in the pH range 8 to 14, preferably in the pH range 8.5 to 14, and particularly 2 i S 1 3 2 3 - 4 - O.g. 4849 preferably in the range 9 to 14, leads to extremely high yields of dichloromalonic esters co~bined with estremely high product purities.
The pH range in which the desired reaction is carried out lies in a wide range. Thus, on the one hand, account should be taken of the stability of the hypochlorites used by a pH ~ 8 and, on the other hand, the pH should be re~tricted in the alkalinity of the reaction mixture to achieve optimal yields, that is to say to avoid losses of precursor and desired product as a consequence of hydro-lysis reactions; for this reason it i8 expedient for the upper limit of the reaction pH to be limited to ~ 14. The preferred pH range is 8.5 to 14.
It has furthermore been found that low reaction tempera-tures are beneficial for the yields and product puritywhich can be achieved. The temperature range is therefore expediently from 0 to 50C, and the preferred temperature range is from 2 to 25C. This temperature range ensures fast and mild reaction of the precursors used; however, it is also possible to use lower temperatures.
The described reaction can be carried out, for example, by initially introducing the hypochlorite in the form of an aqueous solution or suspension, and metering in the precursor while maintaining the pH range constant, as described above, by metering of one of the acids described above, which takes place in parallel, it also being possible to continue the acid metering in the after-reaction phase to maintain the chosen pH range.
However, a reverse procedure may also be chosen, that is to say initial introduction of the precursor and metering of the hypochlorite solution in addition to the acid metering.
It is possible and expedient in the malonic ester chlori-nation to be carried out using hypochlorites for a slight 21S1323 ~ `
_ 5 _ O.Z. 48~49 excess of hypochlorite to be used, based on the mnlonic esters used; the eXCQ88 to be U8Qd i8 not critical. In general, 2 to 20%, preferably 5 to 10%, excess of hypo-halite are used. The malonic ester/hypochlorite ratios are from 1 : 1 to 1 : 2, preferably from 1 : 1.05 to 1 :
1.2. After the end of the reaction, this hypochlorite content which is still present is decomposed in a known manner, for example by A~ g a~ueous ~odiu~ ~ulphite where appropriate.
These reactions generally result in a two-phase reaction mixture from which it is easy to remove the organic phase. In this connection, it is expedient to remove desired product which is still dissolved in the resulting aqueous phase using a suitable extractant.
Extractants which are suitably used are preferably solvents which are immiscible with water, such as halogenated hydrocarbons, aliphatic, cycloaliphatic and aromatic hydrocarbons, esters and ethers, which can easily be removed after the extraction from the desired product, for example by normal or fractional vacuum distillation.
The following examples demonstrate the range of applica-tion of the process which has been devised.
Example 1 217.8 g of aqueous sodium hypochlorite solution (content:
8.55% NaOCl equivalent to 250 mmol of NaOCl) are cooled to 5C, and the pH of the solution is adjusted to about 9.1 by adding aqueous 20% strength hydrochloric acid.
36.0 g of diethyl malonate (225 mmol) are added dropwise over the course of about 30 minutes to this cooled initial solution, maint~i n; ng the pH of the solution in the range 9.0 to 9.2 by the simultaneous metering of an aqueous 20% strength hydrochloric acid, and maint~ining the internal temperature at about 5~C by cooling.
~ 2 1 5 1 3 2 3 - - 6 - O.Z. 4849 After the metering of malonic ester is complete, reaction is allowed to continue for 10 minute~ while ~ainta~ning the pH range constant. Then excess sodium hypochlorite which is still present is decomposed by adding sodium sulphite, the organic phase is removed from the 2-phase mixture, the aqueous phase is exhaustively extracted with tert-butyl methyl ether, and the organic phase and extracts are combined.
After evaporation of this solution, the resulting residue is sub~ected to vacuum di~tillation. 50.8 g of diethyl 2,2-dichloromalonate of boiling point 95 to 96C (S hPa) are obtained, which is equivalent to a yield of 98.6% of theory; the purity of the product determined by gas chromatography is ~ 99.5%, the content of monochloro compound is ' 0.2%.
ExamPle 2 In analogy to Example 1 but using 48.6 g of diisobutyl malonate (225 mmol). The initial and reaction pH range is 12.0 to 12.2.
After analogous ~ Jl~U~ 58.0 g of diisobutyl 2,2-di-chloromalonate of boiling point 114 to 117C (5 hPa) are obtained (purity of the desired product: > 99.3%), which is equivalent to a yield of 90.4% of theory.
Example 3 In analogy to Example 1 but using 29.7 g of dimethyl malonate (225 mmol).
Analogous workup results in 39.9 g of dimethyl 2,2-di-chloromalonate of boiling point 72 to 73C (5 hPa) (purity: > 99.5~), which is equivalent to a yield of 88.2~ of theory.
- ~ = 2 1 ~ 1 3 ~ J
~- 7 - O.Z. 48~9 Exam~le 4 In analogy to Example 1 but using 42.3 g of diisG~o~yl malonate (225 mmol). The reaction i8 started at pH 13 and carried out in the range 13.0 to 13.5, with the after-reaction time being about 60 minutes.
Analogous workup results in 52.5 g of diisopropyl 2,2-di-chloromalonate of boiling point 92 to 93C (5 hPa) (purity: 2 99.5%), which is equivalent to a yield of 90.8% of theory.
ExamPle 5 In analogy to Example 4 but using 42.3 g of tert-butyl ethyl malonate (225 mmol). The reaction and after-reac-tion is carried out in the temperature range 20 to 22C.
Analogous workup results in 48.8 g of tert-butyl ethyl 2,2-dichloromalonate of boiling point 95 to 96C (5 hPa) (purity: > 98%), which is equivalent to a yield of 84.4 of theory.
Example 6 Analogous to Example 4 but using 39.2 g of tert-butyl methyl malonate (225 mmol).
Analogous workup results in 46.8 g of tert-butyl methyl 2,2-dichloromalonate of boiling point 86 to 88C (5 hPa) (purity: > 99%), which is equivalent to a yield of 85.2 of theory.
.
Claims (18)
1. Process for preparing a 2,2-dichloromalonic diester of the general formula in which R1 and R2 each are straight-chain or branched alkyl with 1 to 6 C atoms, cycloalkyl or aralkyl, and the radicals R1 and R2 can be identical or different, which process comprises reacting a malonic diester of the general formula in which R1 and R2 are straight-chain or branched C1- to C6-alkyl, cycloalkyl or aralkyl, and the radicals R1 and R2 can be identical or different, with an aqueous alkali metal or alkaline earth metal hypochlorite solution in alkaline medium at a pH
value from 8 to 14 and a low temperature from below 0 to 50°C
while simultaneously maintaining a selected pH range constant by addition in parallel of an acid.
value from 8 to 14 and a low temperature from below 0 to 50°C
while simultaneously maintaining a selected pH range constant by addition in parallel of an acid.
2. Process according to claim 1, wherein R1 and R2 each are C1-C6alkyl, C3-C6cycloalkyl or ara(C1-C6)alkyl.
3. Process according to claim 1, wherein R1 and R2 each are C1-C4alkyl or phenyl(C1-C6)alkyl.
4. Process according to claim 1, wherein R1 and R2 each are methyl, ethyl, propyl or butyl.
5. Process according to claim 1, wherein a stoichiometric excess aqueous alkali metal or alkaline earth metal hypochlorite solution is employed.
6. Process according to claim 1, wherein the reaction is carried out at a pH value from 8.5 to 14.
7. Process according to claim 1, wherein the reaction is carried out at a pH value from 9 to 14.
8. Process according to claim 1, wherein said acid used to maintain the selected pH range is a dilute aqueous mineral acid, or aliphatic carboxylic acid or a dilute aromatic carboxylic acid.
9. Process according to claim 8, wherein said dilute aqueous mineral acid is selected from the group consisting of hydrochloric, sulphuric and phosphoric acids.
10. Process according to claim 8, wherein said aliphatic carboxylic acid is diluted.
11. Process according to claim 8, wherein said aliphatic carboxylic acid is substituted by a radical which is inert under reaction conditions.
12. Process according to claim 8, wherein said aliphatic carboxylic acid is selected from the group consisting of formic, acetic and propionic acids and monochloro, dichloro and trichloroacetic acids.
13. Process according to claim 8, wherein said aromatic carboxylic acid is substituted by one or more radicals inert under reaction conditions.
14. Process according to any one of claims 1 to 13, wherein the reaction is carried out in the temperature range 2 to 25°C.
15. Process according to any one of claims 1 to 13, wherein the reaction is carried out with a malonic ester/hypochlorite ratio of 1 : 1 to 1 : 2.
16. Process according to any one of claims 1 to 13, wherein the reaction is carried out with a malonic ester/hypochlorite ratio of 1 : 1.05 to 1 : 1.2.
17. Process according to any one of claims 1 to 13, wherein the hypochlorite is present as an aqueous solution or as an aqueous suspension.
18. Process according to any one of claims 1 to 13, wherein one of the two reactants is metered into the reaction mixture during the reaction.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4420263.6 | 1994-06-10 | ||
| DE19944420263 DE4420263A1 (en) | 1994-06-10 | 1994-06-10 | 2,2-di:chloro:malonic di:ester prepn. from readily available cpds. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2151323A1 true CA2151323A1 (en) | 1995-12-11 |
Family
ID=6520239
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2151323 Abandoned CA2151323A1 (en) | 1994-06-10 | 1995-06-08 | Process for the preparation of 2,2-dichloromalonic diesters |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0687665A1 (en) |
| JP (1) | JPH07330674A (en) |
| CA (1) | CA2151323A1 (en) |
| DE (1) | DE4420263A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19509377A1 (en) * | 1995-03-15 | 1996-09-19 | Huels Chemische Werke Ag | Process for the preparation of 2-aryl-2-chloromonic acid diesters |
| JP4598486B2 (en) * | 2004-11-17 | 2010-12-15 | 三井化学株式会社 | Method for producing 1,5-diaminonaphthalene |
| WO2017100985A1 (en) * | 2015-12-14 | 2017-06-22 | 苏州大学张家港工业技术研究院 | Preparation method for 2,2-dihalo-1,3-dicarbonyl derivatives |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2018952A1 (en) * | 1968-09-26 | 1970-06-26 | Procter & Gamble | |
| CH599092A5 (en) * | 1975-07-17 | 1978-05-12 | Rotel Ag | 2,2-Di-chloro-malonic acid prepn. |
| US5064518A (en) * | 1990-01-29 | 1991-11-12 | The Dow Chemical Company | Method for the selective alpha halogenation of alkylaromatic compounds |
-
1994
- 1994-06-10 DE DE19944420263 patent/DE4420263A1/en not_active Withdrawn
-
1995
- 1995-04-12 EP EP95105567A patent/EP0687665A1/en not_active Withdrawn
- 1995-06-08 CA CA 2151323 patent/CA2151323A1/en not_active Abandoned
- 1995-06-08 JP JP14216695A patent/JPH07330674A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0687665A1 (en) | 1995-12-20 |
| JPH07330674A (en) | 1995-12-19 |
| DE4420263A1 (en) | 1995-12-14 |
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