Method for preparation of 4-alkoxy-1,1,1-trifluorobut-3-en-2-ones from 1,1,1-trifluoroacetone

Abstract

The invention discloses a method for the preparation of 4-alkoxy-1,1,1-trifluorobut-3-en-2-ones from 1,1,1-trifluoroacetone.

Claims

1. A method for the preparation of a compound of formula (I); ##STR00008## the method comprises step StepS1 comprising a reaction ReacS1; wherein reaction ReacS1 is a reaction of a compound of formula (II) with 1,1,1-trifluoroacetone in the presence of a compound of formula (IV); ##STR00009## wherein R1 is C.sub.1-4 alkyl; R4 and R5 are identical or different and independently from each other selected from the group consisting of H and C.sub.1-4 alkyl.

2. The method according to claim 1, wherein R1 is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl and n-butyl.

3. The method according to claim 1, wherein R4 and R5 are identical or different and independently from each other selected from the group consisting of hydrogen and C.sub.1-2 alkyl.

4. The method according to claim 1, wherein the molar amount of the compound of formula (II) is from 1 to 20 times based on the molar amount of 1,1,1-trifluoroacetone.

5. The method according to claim 1, wherein the molar amount of the compound of formula (IV) is from 2 to 60 times based on the molar amount of 1,1,1-trifluoroacetone.

6. The method according to claim 1, wherein reaction ReacS1 is done in the presence of a catalyst CatS1; wherein catalyst CatS1 is selected from the group consisting of trifluoroacetic acid, sulfuric acid, ZnCl.sub.2, ZnBr.sub.2, ZnI.sub.2, BF.sub.3, BF.sub.3OEt.sub.2, BBr.sub.3, BCl.sub.3, MgCl.sub.2, and CaCl.sub.2.

7. The method according to claim 6, wherein the molar amount of the catalyst CatS1 is from 0.001 to 2 times based on the molar amount of 1,1,1-trifluoroacetone.

8. The method according to claim 1, wherein reaction ReacS1 is done at a temperature of from 0 C. to 250 C.

9. The method according to claim 1, wherein the reaction time of reaction ReacS1 is from 10 min to 72 h.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) Compound of formula (II), 1,1,1-trifluoroacetone and compound of formula (IV) can be mixed for the reaction ReacS1 in any order.

(2) Preferably, R1, is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl and n-butyl; more preferably, R1 is selected from the group consisting of methyl, ethyl and n-propyl; even more preferably, R1 is methyl or ethyl; especially, R1 is ethyl.

(3) Preferably, R4 and R5 are identical or different and independently from each other selected from the group consisting of hydrogen and C.sub.1-2 alkyl; more preferably, R4 and R5 are identical or different and independently from each other selected from the group consisting of hydrogen and methyl; even more preferably, R4 and R5 are identical or different and independently from each other hydrogen or methyl; especially, R4 and R5 are methyl.

(4) Preferably, the molar amount of compound (II) is from 1 to 20 times, more preferably from 1 to 10 times, and even more preferably from 1 to 6 times, based on the molar amount of 1,1,1-trifluoroacetone.

(5) Preferably, the molar amount of compound (IV) is from 2 to 60 times, more preferably from 2 to 20 times, and even more preferably from 2 to 10 times, based on the molar amount of 1,1,1-trifluoroacetone.

(6) Reaction ReacS1 can be done in the presence of a catalyst CatS1; catalyst CatS1 is selected from the group consisting of trifluoroacetic acid, sulfuric acid, ZnCl.sub.2, ZnBr.sub.2, ZnI.sub.2, BF.sub.3, BF.sub.3OEt.sub.2, BBr.sub.3, BCl.sub.3, MgCl.sub.2, and CaCl.sub.2; preferably, catalyst CatS1 is selected from the group consisting of trifluoroacetic acid, sulfuric acid, ZnCl.sub.2, ZnBr.sub.2, ZnI.sub.2, BF.sub.3OEt.sub.2, BCl.sub.3, MgCl.sub.2, and CaCl.sub.2; more preferably, catalyst CatS1 is selected from the group consisting of trifluoroacetic acid, sulfuric acid, ZnCl.sub.2, BF.sub.3OEt.sub.2, MgCl.sub.2, and CaCl.sub.2; even more preferably, catalyst CatS1 is selected from the group consisting of trifluoroacetic acid, ZnCl.sub.2, BF.sub.3OEt.sub.2, and MgCl.sub.2;

(7) Preferably, the molar amount of catalyst CatS1 is from 0.001 to 2 times, more preferably from 0.005 to 1 times, and even more preferably from 0.01 to 0.5 times, based on the molar amount of 1,1,1-trifluoroacetone.

(8) Preferably, reaction ReacS1 is done at a temperature of from 0 C. to 250 C., more preferably from 20 C. to 200 C., even more preferably from 60 C. to 150 C.

(9) Preferably, reaction ReacS1 is done at a pressure of from ambient pressure to 150 bar, more preferably from ambient pressure to 100 bar, even more preferably from ambient pressure to 70 bar.

(10) Preferably, the reaction time of reaction ReacS1 is from 10 min to 72 h, more preferably from 1 h to 48 h, even more preferably from 2 h to 24 h.

(11) Reaction (ReacS1) can be done in a solvent; preferably, the solvent is a solvent (SolvS1) and solvent (SolvS1) is selected from the group consisting of ethyl acetate, butyl acetate, dichloromethane, 1,2-dichloroethane, chloroform, acetonitrile, propionitrile, DMF, DMA, DMSO, sulfolane, THF, 2-methyl-THF, 3-methyl-THF, dioxane, 1,2-dimethoxyethane, toluene, benzene, chlorobenzene, nitrobenzene, and mixtures thereof; more preferably, solvent (SolvS1) is selected from the group consisting of ethyl acetate, butyl acetate, dichloromethane, 1,2-dichloroethane, acetonitrile, propionitrile, DMF, DMA, DMSO, sulfolane, THF, 2-methyl-THF, 3-methyl-THF, dioxane, 1,2-dimethoxyethane, toluene, benzene, chlorobenzene, and mixtures thereof; even more preferably, solvent (SolvS1) is selected from the group consisting of ethyl acetate, butyl acetate, dichloromethane, 1,2-dichloroethane, acetonitrile, DMF, DMA, sulfolane, dioxane, 1,2-dimethoxyethane, toluene, chlorobenzene, and mixtures thereof; especially, solvent (SolvS1) is selected from the group consisting of ethyl acetate, butyl acetate, dichloromethane, 1,2-dichloroethane, acetonitrile, DMF, DMA, dioxane, 1,2-dimethoxyethane, toluene, chlorobenzene, and mixtures thereof.

(12) Preferably, the weight of solvent (SolvS1) is from 0.1 to 100 times, more preferably from 1 to 50 times, even more preferably from 1 to 25 times, of the weight of 1,1,1-trifluoroacetone.

(13) After reaction ReacS1, any catalyst CatS1 can be removed by filtration. Compound of formula (I) can be isolated after the reaction ReacS1 by any conventional method, for instance by distillation under reduced pressure or by crystallization. Preferably, any volatile byproduct is distilled off, and the residue is purified or used without further purification.

EXAMPLES

Example 1

(14) A mixture of 1,1,1-trifluoroacetone (0.80 ml, 8.93 mmol), triethylorthoformate (2.23 ml, 13.0 mmol) and acetic anhydride (2.53 ml, 27.0 mmol) was stirred in a closed vial at 140 C. for 16 h.

(15) Analysis of a sample by .sup.1H NMR (CDCl.sub.3) indicated formation of compound of formula (1) in 65% yield with respect to 1,1,1-trifluoroacetone used.

(16) ##STR00006##

Examples 2 to 5

(17) Examples 2 to 5 were done in the same way as example 1, with any differences as given in Table 1.

(18) TABLE-US-00001 TABLE 1 Molar Ratio HC(OEt).sub.3 TriFA Ac.sub.2O (II)/TriFA/ Temp Time yield Example [mmol] [mmol] [mmol] (IV) [ C.] [h] [%] 2 18 4.5 27 4/1/6 140 10 41 3 2.67 1.34 4 2/1/3 120 12 15 4 7.07 3.57 10.7 2/1/3 130 21 37 5 6.68 2.23 13.4 3/1/6 130 21 51

Example 6

(19) A mixture of 1,1,1-trifluoroacetone (0.20 ml, 2.2 mmol), trimethylorthoformate (1.0 ml, 9.1 mmol), and acetic anhydride (1.6 ml, 16.9 mmol) was stirred in a closed vial at 140 C. for 16 h. Analysis of a sample by 1H NMR (CDCl.sub.3) indicated formation of compound of formula (2) in 78% yield with respect to trifluoroacetone used.

(20) ##STR00007##

(21) .sup.1H NMR (CDCl.sub.3, 400 MHz) delta=3.88 (s, 3H), 5.87 (d, J=12 Hz, 1H), 7.94 (d, J=12 Hz, 1H).

(22) .sup.19F NMR (CDCl.sub.3) delta=78.08 ppm.