USRE32717E - Method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide - Google Patents
Method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide Download PDFInfo
- Publication number
- USRE32717E USRE32717E US07/109,775 US10977587A USRE32717E US RE32717 E USRE32717 E US RE32717E US 10977587 A US10977587 A US 10977587A US RE32717 E USRE32717 E US RE32717E
- Authority
- US
- United States
- Prior art keywords
- methyl
- trimethylsilyl
- trifluoroacetamide
- preparation
- reaction
- 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.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims abstract description 15
- MSPCIZMDDUQPGJ-UHFFFAOYSA-N N-methyl-N-(trimethylsilyl)trifluoroacetamide Chemical compound C[Si](C)(C)N(C)C(=O)C(F)(F)F MSPCIZMDDUQPGJ-UHFFFAOYSA-N 0.000 title claims abstract description 13
- 238000002360 preparation method Methods 0.000 title claims description 9
- IQNHBUQSOSYAJU-UHFFFAOYSA-N 2,2,2-trifluoro-n-methylacetamide Chemical compound CNC(=O)C(F)(F)F IQNHBUQSOSYAJU-UHFFFAOYSA-N 0.000 claims abstract description 10
- SIOVKLKJSOKLIF-HJWRWDBZSA-N trimethylsilyl (1z)-n-trimethylsilylethanimidate Chemical compound C[Si](C)(C)OC(/C)=N\[Si](C)(C)C SIOVKLKJSOKLIF-HJWRWDBZSA-N 0.000 claims abstract description 9
- 239000011541 reaction mixture Substances 0.000 claims description 16
- 238000010438 heat treatment Methods 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 abstract description 12
- 239000000376 reactant Substances 0.000 abstract description 8
- 238000001914 filtration Methods 0.000 abstract description 6
- 238000004821 distillation Methods 0.000 abstract description 5
- 239000006227 byproduct Substances 0.000 abstract description 4
- 150000003839 salts Chemical class 0.000 abstract description 2
- 238000007796 conventional method Methods 0.000 abstract 1
- 239000000047 product Substances 0.000 description 10
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 9
- -1 silane compound Chemical class 0.000 description 7
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 6
- IJOOHPMOJXWVHK-UHFFFAOYSA-N chlorotrimethylsilane Chemical compound C[Si](C)(C)Cl IJOOHPMOJXWVHK-UHFFFAOYSA-N 0.000 description 4
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 238000013019 agitation Methods 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000007033 dehydrochlorination reaction Methods 0.000 description 2
- 230000000873 masking effect Effects 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 239000005051 trimethylchlorosilane Substances 0.000 description 2
- 239000005046 Chlorosilane Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 239000003242 anti bacterial agent Substances 0.000 description 1
- 229940088710 antibiotic agent Drugs 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- LWFWUJCJKPUZLV-UHFFFAOYSA-N n-trimethylsilylacetamide Chemical compound CC(=O)N[Si](C)(C)C LWFWUJCJKPUZLV-UHFFFAOYSA-N 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 125000003808 silyl group Chemical group [H][Si]([H])([H])[*] 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 229940086542 triethylamine Drugs 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
- C07F7/02—Silicon compounds
- C07F7/08—Compounds having one or more C—Si linkages
- C07F7/10—Compounds having one or more C—Si linkages containing nitrogen having a Si-N linkage
Definitions
- the present invention relates to a method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide or, more particularly, to an industrially advantageous method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide without using corrosive reactants and with omission of the troublesome procedure of filtration to remove the precipitates of a by-product salt.
- N-Methyl-N-trimethylsilyl trifluoroacetamide as the subject material of the inventive method is a useful compound as a neutral masking agent, i.e. a masking reactant for active hydrogen atoms utilizing the silyl group, in the semi-synthetic process of various antibiotics or derivatives thereof.
- N-methyl trifluoroacetamide is subjected to a dehydrochlorination reaction with trimethyl chlorosilane by adding the silane compound dropwise into a reaction mixture of N-methyl trifluoroacetamide and a tertiary amine compound, e.g. triethyl amine, as an acceptor of hydrogen chloride diluted with an organic solvent such as benzene, hexane and the like.
- a tertiary amine compound e.g. triethyl amine
- the reaction mixture after completion of the dehydrochlorination reaction must be filtered to remove the precipitates of the amine hydrochloride while the filtration cannot be performed without the problem of emission of a large volume of white fume by the reaction of the atmospheric moisture with the teritary amine compound and trimethyl chlorosilane remaining in the reaction mixture to cause serious environmental pollution if not to mention the decrease in the yield of the product by the filtration and hydrolysis of the product compound during filtration.
- the chlorosilane compound as one of the reactants is very corrosive against metals so that the production cost is necessarily high due to the expensiveness of the corrosion-resistant apparatus used in the preparation.
- the method of the invention for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide developed as a result of investigations to solve the above described problems and disadvantages in the prior art method, comprises:
- the principle of the inventive method is the reaction of N-methyl trifluoroacetamide and N,O-bis(trimethylsilyl) acetamide, which can be prepared according to the disclosure in U.S. Pat. No. 3,397,220, according to the following reaction equation, in which Me denotes a methyl group:
- the velocity of this reaction is low at room temperature so that the reaction mixture should be heated at a temperature in the range from 40° to 130° C.
- the temperature is lower than 40° C.
- the reaction proceeds so slowly that the yield of the desired product cannot be high enough within a reasonable time of reaction while the N,O-bis(trimethylsilyl) acetamide may be subject to thermal decomposition when the reaction mixture is heated at a temperature higher than 130° C. also to decrease the yield of the desired product.
- the reaction is usually complete within 2 to 4 hours.
- the amount of N,O-bis(trimethylsilyl) acetamide is somewhat larger than equimolar to N-methyl trifluoroacetamide or the molar ratio of the former reactant to the latter reactant should be in the range from 1:1 to 1.3:1 in consideration of the balance between the yield of the product and the cost for the reactants.
- the reaction mixture may be diluted with an organic solvent such as hydrocarbons, e.g. benzene and hexane, if necessary, although the reaction can proceed without using any solvent.
- the reaction mixture is first freed from the solvent, when used, by distillation and then subjected to fractionating distillation under reduced pressure at a temperature of 130° C. or below to isolate the desired product of N-methyl-N-trimethylsilyl trifluoroacetamide.
- the yield of the product is usually at least 90% of the theoretical value.
- N-Trimethylsilyl acetamide produced as a by-product is also useful as a silylating agent.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
Abstract
N-Methyl-N-trimethylsilyl trifluoroacetamide can be synthesized by the reaction of N-methyl trifluoroacetamide and, N,O-bis(trimethylsilyl) acetamide at 40°-130° C. followed by fractionating distillation. The method is advantageous in respect of the absence of the step of filtration for the removal of the by-product salt and non-use of any corrosive reactant in comparison with conventional methods.
Description
The present invention relates to a method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide or, more particularly, to an industrially advantageous method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide without using corrosive reactants and with omission of the troublesome procedure of filtration to remove the precipitates of a by-product salt.
N-Methyl-N-trimethylsilyl trifluoroacetamide as the subject material of the inventive method is a useful compound as a neutral masking agent, i.e. a masking reactant for active hydrogen atoms utilizing the silyl group, in the semi-synthetic process of various antibiotics or derivatives thereof.
It is known and conventionally practiced in the synthetic preparation of N-methyl-N-trimethylsilyl trifluoroacetamide that N-methyl trifluoroacetamide is subjected to a dehydrochlorination reaction with trimethyl chlorosilane by adding the silane compound dropwise into a reaction mixture of N-methyl trifluoroacetamide and a tertiary amine compound, e.g. triethyl amine, as an acceptor of hydrogen chloride diluted with an organic solvent such as benzene, hexane and the like.
This method, however, is disadvantageous in several respects. For example, the reaction mixture after completion of the dehydrochlorination reaction must be filtered to remove the precipitates of the amine hydrochloride while the filtration cannot be performed without the problem of emission of a large volume of white fume by the reaction of the atmospheric moisture with the teritary amine compound and trimethyl chlorosilane remaining in the reaction mixture to cause serious environmental pollution if not to mention the decrease in the yield of the product by the filtration and hydrolysis of the product compound during filtration. Moreover, the chlorosilane compound as one of the reactants is very corrosive against metals so that the production cost is necessarily high due to the expensiveness of the corrosion-resistant apparatus used in the preparation.
Thus, the method of the invention for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide, developed as a result of investigations to solve the above described problems and disadvantages in the prior art method, comprises:
(a) mixing N-methyl trifluoroacetamide and N,O-bis(trimethylsilyl) acetamide to form a reaction mixture; and
(b) heating the reaction mixture.
The reaction of the reactants above mentioned, neither of them being corrosive, proceeds so smoothly without producing any precipitates as a by-product that no filtration of the reaction mixture after completion of the reaction is necessary and the desired product can be isolated by merely fractionating the reaction mixture by distillation.
As is described above, the principle of the inventive method is the reaction of N-methyl trifluoroacetamide and N,O-bis(trimethylsilyl) acetamide, which can be prepared according to the disclosure in U.S. Pat. No. 3,397,220, according to the following reaction equation, in which Me denotes a methyl group:
CF.sub.3 CO--NMe--H+Me.sub.3 Si--O--CMe═NSiMe.sub.3 →CF.sub.3 CO--NMe--SiMe.sub.3 +MeCO--NH--SiMe.sub.3 (I)
The velocity of this reaction is low at room temperature so that the reaction mixture should be heated at a temperature in the range from 40° to 130° C. When the temperature is lower than 40° C., the reaction proceeds so slowly that the yield of the desired product cannot be high enough within a reasonable time of reaction while the N,O-bis(trimethylsilyl) acetamide may be subject to thermal decomposition when the reaction mixture is heated at a temperature higher than 130° C. also to decrease the yield of the desired product. The reaction is usually complete within 2 to 4 hours. It is preferable that the amount of N,O-bis(trimethylsilyl) acetamide is somewhat larger than equimolar to N-methyl trifluoroacetamide or the molar ratio of the former reactant to the latter reactant should be in the range from 1:1 to 1.3:1 in consideration of the balance between the yield of the product and the cost for the reactants. The reaction mixture may be diluted with an organic solvent such as hydrocarbons, e.g. benzene and hexane, if necessary, although the reaction can proceed without using any solvent.
When the reaction is completed in the above described manner, the reaction mixture is first freed from the solvent, when used, by distillation and then subjected to fractionating distillation under reduced pressure at a temperature of 130° C. or below to isolate the desired product of N-methyl-N-trimethylsilyl trifluoroacetamide. The yield of the product is usually at least 90% of the theoretical value. N-Trimethylsilyl acetamide produced as a by-product is also useful as a silylating agent.
In the following, examples are given to illustrate the inventive method in more detail.
Into a three-necked flask of 2-liter capacity equipped with a stirrer, reflux condenser and thermometer were introduced 254 g (2.00 moles) of N-methyl trifluoroacetamide, 528 g (2.60 moles) of N,O-bis(trimethylsilyl) acetamide and 400 ml of benzene to form a reaction mixture, which was heated at 80° C. under agitation for 3 hours. After cooling, the solvent was removed from the mixture by distillation and the remaining mixture was distilled under reduced pressure to give 364 g of a fraction boiling at 52° to 54° C. under a pressure of 40 mmHg, which was identified to be N-methyl-N-trimethylsilyl trifluoroacetamide. The yield of the product was 91% of the theoretical value.
Into a three-necked flask of 500-ml capacity equipped with a stirrer, reflux condenser and thermometer were introduced 127 g (1.00 mole) of N-methyl trifluoroacetamide and 244 g (1.20 moles) of N,O-bis(trimethylsilyl) acetamide to form a reaction mixture, which was heated at 100° C. under agitation for 4 hours. After cooling, the mixture was distilled under reduced pressure to give 188 g of a fraction boiling at 52° to 54° C. under a pressure of 40 mmHg, which was identififed to be N-methyl-N-trimethylsilyl trifluoroacetamide. The yield of the product was 94% of the theoretical value.
Claims (3)
1. A method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide which comprises:
(a) mixing N-methyl trifluoroacetamide and N,O-bis(trimethylsilyl) acetamide to form a reaction mixture; and
(b) heating the reaction mixture.
2. The method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide as claimed in claim 1 wherein the reaction mixture is heated at a temperature in the range from 40° to 130° C.
3. The method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide as claimed in claim 1 wherein N-methyl trifluoroacetamide and N,O-bis(trimethylsilyl) acetamide are mixed in a molar ratio in the range from 1:1 to 1:1.3.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18274085A JPS6242991A (en) | 1985-08-20 | 1985-08-20 | Production of n-methyl-n(trimethylsilyl) trifluoroacetamide |
| JP60-182740 | 1985-08-20 | ||
| US06/896,280 US4663471A (en) | 1986-08-14 | 1986-08-14 | Method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US06/896,280 Reissue US4663471A (en) | 1985-08-20 | 1986-08-14 | Method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| USRE32717E true USRE32717E (en) | 1988-07-19 |
Family
ID=26501430
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US07/109,775 Expired - Lifetime USRE32717E (en) | 1985-08-20 | 1987-10-19 | Method for the preparation of N-methyl-N-trimethylsilyl trifluoroacetamide |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | USRE32717E (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3415864A (en) * | 1967-09-11 | 1968-12-10 | Research Corp | Bis-(trimethylsilyl)trifluoroacetamide |
| US3839387A (en) * | 1973-11-14 | 1974-10-01 | Lilly Co Eli | Process for preparing n-trimethyl-silylacetamide |
-
1987
- 1987-10-19 US US07/109,775 patent/USRE32717E/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3415864A (en) * | 1967-09-11 | 1968-12-10 | Research Corp | Bis-(trimethylsilyl)trifluoroacetamide |
| US3839387A (en) * | 1973-11-14 | 1974-10-01 | Lilly Co Eli | Process for preparing n-trimethyl-silylacetamide |
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