13α-18-nor-16-Carboxamido steroids were synthesized via a palladium-catalyzed aminocarbonylation reaction of the corresponding iodoalkenes. The starting material was an unnatural 13α-16-keto steroid, obtained by a Wagner-Meerwein rearrangement of a 16α,17α-epoxide in the presence of [BMIM][BF4]. The 13α-16-keto steroid was converted to a mixture of 16-iodo-16-ene and 16-iodo-15-ene derivatives in two
Diols are efficient co-catalysts in guanidine catalysedcondensation of ketones and aldehydes. According to quantum chemical calculations the acceleration effect can be explained by the formation of complexes of carbonyl compounds and diols held together by double H-bonding. The base/diol mixture can be separated from the product and recycled by reversible CO2 capture and release.
13 alpha-Steroid-ferrocene derivatives were synthesized via two reaction pathways starting from an unnatural 16-keto-18-nor-13 alpha-steroid. The unnatural steroid was converted to ferrocene derivatives via copper-catalyzed azide-alkyne cycloaddition or palladium-catalyzed aminocarbonylation. 16-Azido- and 16-N-(prop-2-ynyl)-carboxamido-steroids were synthesized as starting materials for azide-alkyne cycloaddition with the appropriate ferrocene derivatives. Based on our earlier work, aminocarbonylation of 16-iodo-16-ene and 16-iodo-15-ene derivatives was studied with ferrocenylmethylamine. The new products were obtained in moderate to good yields and were characterized by H-1 and C-13 NMR, IR and MS. The solid state structure of the starting material 13 alpha-18-norandrostan-16-one and two carboxamide products were determined by X-ray crystallography. Evidences were provided that the N-propargyl-carboxamide compound as well as its ferrocenylmethyltriazole derivative are able to decrease the activation of TRPV1 receptor on TRG neurons. (C) 2015 Elsevier Inc. All rights reserved.
Ionic Liquid-Promoted Wagner–Meerwein Rearrangement of 16α,17α-Epoxyandrostanes and 16α,17α-Epoxyestranes
Ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([bmitn](+)[PF(6)](-)) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim](-)(+)[BF(4)](-)) were found to promote an unusual Wagner-Meerwein rearrangement of steroidal 16 alpha,17 alpha-epolddes leading to unnatural 13-epi-18-nor-16-one derivatives as the main products. These compounds were isolated in good to excellent yields. 16 alpha-Hydroxy-Delta(13)-18-norsteroid5, the results of the usual rearrangement, were obtained as minor components of the reaction mixtures. The ionic liquid [bmim](+)[PF(6)](-) was shown to induce C-ring aromatization of 16 alpha,17 alpha-epoxyestranes due to the formation of HF, the hydrolysis product of [PF(6)](-). Increasing amounts of HF and [PO(2)F(2)](-) were detected by (19)F and (31)P NMR when the ionic liquid was reused. The structures of the steroidal products, 16-oxo-18-nor-13 alpha-steroid derivatives, 16 alpha-hydroxy-Delta(13)-18-norsteroids, and C-aromatic compounds were determined by two-dimensional NMR techniques and high-resolution mass spectrometry (HRMS). The ionic liquids were recirculated efficiently.
Identification of a Fossil Sterane Biomarker in Crude Oil - an Androstane with a Modified Carbon Skeleton
作者:Matthias Bender、Marc Schmidtmann、Jürgen Rullkötter、Roger E. Summons、Jens Christoffers
DOI:10.1002/ejoc.201300788
日期:2013.9
of four stereoisomers of 3-methyl-A-nor-androstane (4 % overall yield) was prepared by ionic hydrogenation of the olefin after A-ring recyclization in three steps. 17-Methyl-18-nor-androstane was synthesized in four steps as a mixture of isomers (58 % overall yield) from dihydrotestosterone with a Wagner–Meerwein shift of the 13β-methyl group to C-17 as the key step. Pure 17β- and 17α-methyl-18-nor-13α-androstane