Dimethylformamide → methyl (1R,trans) 2,2-dimethyl-3[(E)-2-formylethenyl]-cyclopropane-1-carboxylate

Temperatur

75 °C

A solution of 17.1 ml of lithium methylate in methanol was added over 21/2 hours at ≃75° C. to a solution of 46.8 g of methyl (1R,trans) 2,2-dimethyl-3-formyl-cyclopropane-1-carboxylate, 193.2 g of the product of Step A and 750 ml of dimethylformamide and the mixture was stirred at ≃75° C. for 5 hours and then stood overnight at room temperature. The mixture was poured with stirring into an ice-water mixture and the resulting mixture was extracted with ether. The organic phase was washed with aqueous saturated sodium chloride solution and dried under reduced pressure at 50° C. The residue was dissolved in a solution of 750 ml of tetrahydrofuran and 750 ml of N hydrochloric acid and the solution was stirred at room temperature for 3 hours and was poured into water. The mixture was extracted with ether and the organic phase was washed with aqueous solution bicarbonate solution, with aqueous saturated sodium chloride solution, was dried and evaporated to dryness. The residue was taken up in an 8-2 petroleum ether (b.p.=60°-80° C.)-ethyl acetate mixture and the mixture was vacuum filtered. The filtrate was evaporated to dryness and the residue was chromatographed over silica gel. Elution with an 8-2 petroleum ether-ethyl acetate mixture yielded 37.6 g of methyl (1R,trans) 2,2-dimethyl-3[(E)-2-formylethenyl]-cyclopropane-1-carboxylate with a refractive index of nD28 =1.5018.

1. waitstood overnight at room temperature
2. additionThe mixture was poured
3. extractionthe resulting mixture was extracted with ether
4. washThe organic phase was washed with aqueous saturated sodium chloride solution
5. customdried under reduced pressure at 50° C
6. dissolutionThe residue was dissolved in a solution of 750 ml of tetrahydrofuran and 750 ml of N hydrochloric acid
7. stirringthe solution was stirred at room temperature for 3 hours
8. additionwas poured into water
9. extractionThe mixture was extracted with ether
10. washthe organic phase was washed with aqueous solution bicarbonate solution, with aqueous saturated sodium chloride solution
11. customwas dried
12. customevaporated to dryness
13. filtrationfiltered
14. customThe filtrate was evaporated to dryness
15. customthe residue was chromatographed over silica gel
16. washElution with an 8-2 petroleum ether-ethyl acetate mixture

ORD-Eintrag

ord-71de7933de2b497b8f9dfdeb23815461

Quelldatensatz

uspto-grants-1984_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04431576