Hexamethylphosphoramide → Lithium cyclohexylisopropylamide

Lithium cyclohexylisopropylamide was prepared from cyclohexylisopropylamine (0.07 ml) and n-butyllithium (1.6-M, 0.265 ml) in THF (1 ml). To the resultant was added dropwise a solution of methyl ester (34) (0.1412 g) in THF (4 ml) and stirred for 2 hours. A solution of diphenyl diselenide (0.132 g) and HMPA (0.074 ml) in THF (2 ml) was added, and the mixture was stirred at -70° C. for one hour and -40° C.--30° C. for 1.5 hours. According to the conventional treatment, selenide (35) (0.1247 g) was obtained. Selenide (35) (0.1247 g) was dissolved in ethyl acetate (6 ml) and methanol (4 ml), and stirred at room temperature with aqueous hydrogen peroxide (30%) (0.5 ml) for one hour. The crude product obtained by the conventional treatment was chromatographed (ethyl acetate/hexane (1:6)) to give Δ2 -PGE2 α-methyl ester (36). Yield, 0.091 g.

1. stirringthe mixture was stirred at -70° C. for one hour and -40° C.--30° C. for 1.5 hours

ORD-Eintrag

ord-295fd35276b54adf85d4bcdf365fd3b5

Quelldatensatz

uspto-grants-1992_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05137915