X-Ray analysis of the steroidal isoxazolidine derivatives 2 and 3b, which are formed (the latter as the corresponding diacetate 3a) in the reaction of (Z)-3beta, 17beta-diacetoxy-19-nor-5,10-secoandrost-l(lo)-en-5-one (1) with N-methylhydroxylamine, has revealed that both compounds (and therefore also 3a) have the same cis-1beta,5beta-epoxyimino bridge structure. The conformations of the two molecular skeletons are compared.

Treatment of steroidal isoxazolidines 3a, 3b and 5b with N-methylhydroxylamine hydrochloride in boiling ethanol-pyridine (1:1) solution results in elimination of the CH3NH2fragment, affording products of oxidative hydrolysis 4a, 4b, and 6b, while acid-catalyzed reaction of isoxazolidines 2a, 3a and 5b leads to rearrangement involving the N-CH3 group with formation of the perhydro-3,1-oxazine derivatives 8a, 9a and 10b.

Synthese de 1β,5- et 3β,5- epoxyimino steroides a partir de N-methyl hydroxylamine et de 5,10-secosteroides

AbstractThe secosteroids (I) and (VI) undergo cycloaddition reaction with N‐methylhydroxylamine hydrochloride (II), forming the isoxazolidines (III), (IV), and (VII).

(E)-Δ 1 (10) -unsaturated 5-oxo-5,10-seco-steroids such as 1, react with hydroxylamine and N-methylhydroxylamine to give stereospecifically isoxazolidine derivatives of type 2 and 3, respectively. The molecular structure of isoxazolidine 3a obtained from (E)-3β-acetoxy-5,10-seco-cholest-1 (10)-en-5-one (la) and N-methylhydroxylamine has been determined by X-ray analysis.

AbstractUnder acid‐catalyzed conditions both the E‐ and Z‐19‐nor‐seco ketones (I) undergo transannular cyclization accompanied by aromatization to give the estratrienyl acetates (II).

(E)-Δ*1(10) -unsaturated 5-oxo-5,10-seco-steroids such as 1, react with hydroxylamine and N-methylhydroxylamine to give stereospecifically isoxazolidine derivatives of type 2 and 3, respectively. The molecular structure of isoxazolidine 3a obtained from (E)-3β-acetoxy-5,10-seco-cholest-1 (10)-en-5-one (la) and N-methylhydroxylamine has been determined by X-ray analysis.

The preparation of 19-nor-5α-androstane 3β,5, 17β-triol 3,17 diacetate (10) is described. When this alcohol was treated with the mercuric oxide-iodine reagent it underwent fragmentation of the C(5)–C(10) bond with formation of a new type of 10-membered ring containing 5,10-seco-steroidal compounds, i.e. (Z)-and (E)-19-nor- 3β, 17β diacetoxy-5,10-seco-androst-1(10)-en-5-one (11 and 12), in 27 and 49% yield, respectively.

In the lead tetraacetate and heavy metal-bromine oxidations of 5,5,5-triphenyl-1-pentanol 1d, the major cyclization product obtained was the rearranged 2,2,3-triphenyltetrahydro-2H-pyran 11d, resulting from homolytic and heterolytic 1,2-phenyl group shift (the latter only in the lead tetraacetate reaction) in the respective intermediate species with electron deficient δ-carbon 4d and 6d.

Cyclohexanemethanol, 1-methylcyclohexanemethanol and 2-tetrahydropyranmethanol were oxidized with lead tetraacetate, and in each case a different ratio of cyclization products (1,4-ethers) to β-fragmentation products (olefins, bridged saturated hydrocarbons, acetates and formates) was obtained. These relative product distributions are discussed in terms of conformational, steric (van der Waals) and electronic (resonance) effects.

Cyclohexanemethanol, 1-methylcyclohexanemethanol and 2-tetrahydropyranmethanol were oxidized with lead tetraacetate, and in each case a different ratio of cyclization products (1,4-ethers) to β-fragmentation products (olefins, bridged saturated hydrocarbons, acetates and formates) was obtained. These relative product distributions are discussed in terms of conformational, steric (van der Waals) and electronic (resonance) effects.