Reaktion #55562

Reaktionsgleichung

9-ethylenedioxy-15-keto-16,16,19-trimethyl-prosta-13,18-dienoic acid, methyl ester

sodium borohydride

→

residue

9-keto-15-hydroxy-16,16,19-trimethyl-prosta-13,18-dienoic acid, methyl ester

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeis kept under 35° C
2. 2
   workup.ADDITIONdiluted with 300 ml
3. 3
   Extraktionof water and extracted with ethyl acetate (3×100 ml)
4. 4
   WaschenThe organic layer is washed with water to neutrality
5. 5
   Trocknendried over Na2SO4
6. 6
   Sonstigethe solvent is evaporated in vacuo

Vorschrift

To a solution of 9-ethylenedioxy-15-keto-16,16,19-trimethyl-prosta-13,18-dienoic acid, methyl ester, (5.2 g.) in methanol (40 ml.), 0.89 g of sodium borohydride are gradually added, while the temperature is kept under 35° C. The mixture is stirred for 30 minutes, then diluted with 300 ml. of water and extracted with ethyl acetate (3×100 ml). The organic layer is washed with water to neutrality, dried over Na2SO4 and the solvent is evaporated in vacuo, to obtain a residue (4.9 g) which is suspended in acetic acid 65% (60 ml.) and stirred at room temperature for 60 minutes. The so obtained solution is diluted with water (200 ml.) and extracted with diethyl ether (3×100 ml). The organic phase is washed with an aqueous, saturated solution of NaHCO3, then with water to neutrality, dried over Na2SO4, and the solvent is evaporated in vacuo. The oily residue (4.2 g. is purified by chromatography on SiO2 (400 g.); the eluent is benzene/ethyl acetate (4:1). One gram of 9-keto-15β-hydroxy-16,16,19-trimethyl-prosta-13,18-dienoic acid, methyl ester, 0.5 g. of 9-keto-15α-hydroxy-16,16,19-trimethyl-prosta-13,18-dienoic acid, methyl ester, and 2.1 g. of a mixture of 15α- and 15β-isomers are obtained.

Quelle