- SILICA GEL PROMOTED SELECTIVE HYDROLYSIS OF 3-METHOXY-2,5(10)-DIENE STEROIDS
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Hydrolysis of 3-methoxy-2,5(10)-diene steroids (1a-c) via oxalic acid in the presence of silica gel was developed as a fast selective synthesis method toward corresponding 5(10)-en-3-ones (2a-c) in good yield (51-94percent).This also provided a new method for selective ketalisation of 17-keto over 3-keto (2c).
- Lui, Li-Gong,Zhang, Tong,Li, Zhen-Su
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p. 2999 - 3006
(2007/10/03)
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- Total synthesis with a chirogenic opening move demonstrated on steroids with estrane or 18a-homoestrane skeleton
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A concept of first choice for the synthesis of the title compounds had been proposed by Dane in the late 1930s. It was soon turned down, because the opening move - a chirogenic Diels-Alder reaction - did not work. With Lewis acids as mediators, however, a successful start has been achieved now. With Ti complexes of chelating ligands (Seebach's TADDOLs (= α,α,α',α'-tetraaryl-1,3-dioxolane-4,5-dimethanols)), enantioselective formation of the desired adducts does occur. Efficient total syntheses of 2 and 3a have been accomplished.
- Quinkert,Del Grosso,Doring,Doring,Schenkel,Bauch,Dambacher,Bats,Zimmermann,Durner
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p. 1345 - 1391
(2007/10/02)
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- Synthesis of gon-4-enes
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1. A therapeutic composition having progestational activity comprising as active ingredient a 17-aliphatic carboxylic acid ester of 17α-ethynyl-18-methyl-19-nortestosterone and a pharmaceutical carrier for said compound.
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- Synthesis of 13-alkyl-gon-4-ones
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The preparation of 13-methylgon-4-enes and novel 13-polycarbonalkylgon-4-enes by a new total synthesis is described. 13-Alkylgon-4-enes having progestational, anabolic and androgenic activities are prepared by forming a tetracylic gonane structure unsaturated in the 1,3,5(10),9(11) and 14-positions, selectively reducing in the B- and C-rings, and converting the aromatic A-ring compounds so-produced to gon-4-enes by Birch reduction and hydrolysis.
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