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During the alkaline methanolysis of 3β-acetoxy-21-chloromethyl-pregn-5-ene-20β-N-phenylurethane, and its p-substituted phenyl derivatives, cyclization occurs, in the course of which 17β-[3-(N-phenyl)tetrahydrooxazin-2-on-6-yl]androst-5-en-3β-ol and its p-substituted phenyl derivatives are formed. The cyclization takes place with (N - -6) neighboring group participation. Oppenauer oxidation...
Steroidal aryliminium salts were prepared from d-seco-pregnene aldehyde 2b, and their BF 3 .OEt 2 -catalyzed reactions were studied. The nature of the substituent R 1 in the anilines 3-6 essentially influenced the chemoselectivity. Using unsubstituted 3, 4-methoxy- (4) or 4-bromoaniline (5), different tetrahydroquinoline derivatives 7a-13a via intramolecular hetero Diels-Alder...
The primary hydroxy functions of 16α-hydroxymethyl-3-methoxy-13α-estra-1,3,5(10)-trien-17β-ol (3a) and 16β-hydroxymethyl-3-methoxy-13α-estra-1,3,5(10)-trien-17α-ol (4a) were stereoselectively transformed into good leaving groups. On alkaline methanolysis of the 16-halomethyl or 16-tolylsulfonyloxymethyl derivatives, a new d-seco-13α-estrone derivative was obtained in high yield.
The epoxidation, the addition of hypobromous acid, and the hydroboration of 3-methoxy-13α-estra-1,3,5(10),16-tetraene 1 with diborane, catecholborane, and 9-BBN were investigated in order to determine the stereochemical outcome and to synthesize new 13α-estra-1,3,5(10)-trienes for biological and conformational investigations. It was shown that the sterically demanding reagent 9-BBN participated in...
An effective epimerization of the normal estrone 3-methyl and 3-benzyl ethers by using o-phenylenediamine and AcOH made the possibility for facile entry into the 13α-estrone series. Combination of this synthetic methodology with an isolation step carried out by means of the Girard-P reagent, the corresponding ethers of 13-epi-estrone were obtained in excellent yields. The 3-hydroxy and 3-methoxy D-homoestrone...
A simple synthetic route has been developed for the synthesis of 16-halo-d-homosteroids in both the normal and 13-epiestrone series by the Lewis acid-catalyzed cyclization of an unsaturated secoestrone aldehyde and its 13α isomer.
16,17-seco-3-Methoxyestra-1,3,5(10),16-tetraen-17-al undergoes intramolecular nitrone 1,3-dipolar cycloaddition with both hydroxylamine and N-methylhydroxylamine to produce a single isoxazolidine isomer in each case. The ring-closures of the hydrazones and the aldazine derived from the secoaldehyde lead to fused N-containing heterocycles via Lewis acid-induced cyclization of the intermediate azomethine...
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