SU212850A1 - - Google Patents

Description

METHOD OF OBTAINING a, p-UNSATURATED KETONE

This invention relates to the field of preparing a conjugated ketone of the formula

CHjOC /; x

SNS SNZ

which can serve as a starting material for the synthesis of chrysanthemic acid.

The proposed method is that 2,2-dimethyl-3-1 {yc- (2-keto) propylcyclopropyl-1-acetaldehyde is subjected to intramolecular aldol condensation in the presence of an aldol condensation catalyst, for example, an alkali metal acetate, acid, base, environment of acetic acid or inert organic solvent at a temperature of from 50 to 200 ° C, preferably from 100 to 150 ° C.

Example 1. 20 g of (-) optically active 2,2 - dimethyl - 3 - cis- (2-oxo) propylcyclopropyl-1-acetaldehyde, obtained from (-b) Dz-caren, is mixed with 60 ml of acetic anhydride and 10 g anhydrous sodium acetate. The mixture is heated for 3 hours at 130 ° C, unmixing. After cooling the reaction CMecii, 100 ml of benzene is added to it and poured onto

shallow ice The benzene layer is then separated and dried over anhydrous sodium sulfate. After distillation of benzene and acetic anhydride, the residual oily product is distilled under vacuum. In this case, 12 g of (H-) 2-acetyl-6, 6-dimethyldicyclo 3, 1, 0 -2-hexane with 40 ° C / 0.5 mm Hg is isolated. Art., HD 1.4865;

m.p. l „ax 262 mmk; E, HE

a D + 252 ° С (СНС1з);

“Film 1675, 1603, 810 s, and-1 NMR chemical max. Shift shift 9,15; 8.80; 8.55; 7.8-7.9; 7.65, 7.4; 3.3 ppm (SCC), semicarbazone, t. Pl. (with decomposition).

Calculated o / o; C, 63.74; And 8.27; N 20.27.

Paideno, o /, -. C, 63.59; H 7.92; N 20.01.

five

Example 2. 10 g of (-) optically active 2,2-dimethyl - 3 - t; "c- (2-oxo) propylzpclopropyl-1-acetaldehyde, obtained from (+) Dzcaren, is mixed with 100 ml of an aqueous lOVo-HO solution caustic soda. The mixture is stirred for 30 minutes at room temperature.

Then it is extracted with benzene, the benzene layer is washed with water and dried over anhydrous sodium sulfate. After distilling off the benzene, the residue is distilled and 6.3 g are obtained.

5 (4-) 2-acetyl-6,6-dimethylbicyclo 3, 1, 0 - 2hexane with m.p. 65-75 ° C / 0.8 mmHg v .; 1,485 each; umakG 1675, 1600, 800 cm. T. pl. 2,4-dpnitrofenilgidrazina 162-163 ° C.

CloHi4O.

Found, o / „: C 77.8; H 8.96.

Calculated Vo: C 58.2; H 5.99; N 17.

CieHigOiN ..

Found, o / „: C 58.3; H 5.48; N 16.6.

Example 3. 10 g of (-) optically active 2,2-dimethyl - 3 - cis - (21-oxo) propyl cyclopropyl-1-acetaldehyde is dissolved in 80: lA of benzene and 20 ml of ethanol. Then 0.5 g of l-toluenesulfonic acid is added as a catalyst. The mixture is heated for 8 hours: with a reflux condenser. At the end of the reaction, another 100 ml of benzene was added and the reaction mixture was washed with water. The benzene layer is dried over anhydrous sulphate.

After distilling off the benzene, the residue is distilled and 8.3 g of (-f) 2-acetyl-6.6-dimethylbicyclo 3, 1, 0 -2-hexane are obtained; T. Kip. 112 ° C / 33 g. Art.

Vychislend, Vo: C 80; H 9.34.

CioHjiO.

Found,%: C 80.3; H 9.03.

A decrease in the freezing temperature in the mixed sample was not determined.

Example 4. 10 g of (-) optically active 2,2 - dimethyl-3-g4 "s- (21-oxo) propylcyclopepsyl-1-acetaldehyde is heated with 200 ml of acetic anhydride for 6 hours at 140 ° C.

Then acetic anhydride is distilled off and the resulting acetic acid under noHHxeHHOii pressure, the residue is distilled, in vacuo, and 3.3 g of {+) 2-acetyl-6,6-dimethylbicyclo-3, 1.0 2-hexane are obtained with a t. . 40-45 ° C / 0.2 Hg Art.

Calculated, o / (: C 80; H 9.34.

.

Found, o / o: C 79; H 8.89.

A decrease in the freezing temperature in the mixed sample was not determined.

Example 5. 10 g of (-) optically active 2,2-dimethyl-3-1 {yc - (21-oxo) propylcycloprophyl-1-acetyldehyde was dissolved in 100 ml of benzene. Then 3 ml of triethylamine are added as a catalyst. The mixture is heated for 2 hours under reflux. At the end of the reaction, the benzene layer is separated, washed with water and dried over anhydrous sodium sulfate. After distilling off the benzene, the residue is distilled in vacuum and 5J g of (- | -) 2-acetyl-6.6-dimethylbicyclo, 1, -hexane with m.p. 50-52 ° C / 0.3 mmHg Art.

Subject invention

Claims (2)

1. The method of obtaining a, | 5-unsaturated ke20 tone of the formula SN OSSNCH SNZ characterized in that 2,2-dimethyl-3- (g /; (2-keto) propyl, clopropyl-1-acetaldehyde is heated at a temperature of from 50 to 200 ° C with an aldol condensation catalyst, for example, an alkali metal acetate, acid, base , in the environment of acetic acid or inert organic solvent. 2. A method according to claim 1, characterized in that the process is carried out at heating from 100 to 150 ° C.