Synthesis of steroid–ferrocene conjugates of steroidal 17-carboxamides via a palladium-catalyzed aminocarbonylation – Copper-catalyzed azide–alkyne cycloaddition reaction sequence
摘要:
Steroids with the 17-iodo-16-ene functionality were converted to ferrocene labeled steroidal 17-carboxamides via a two step reaction sequence. The first step involved the palladium-catalyzed aminocarbonylation of the alkenyl iodides with prop-2-yn-1-amine as the nucleophile in the presence of the Pd(OAc)(2)/ PPh(3) catalyst system. In the second step, the product N-(prop-2-ynyl)-carboxamides underwent a facile azide-alkyne cycloaddition with ferrocenyl azides in the presence of CuSO(4)/sodium ascorbate to produce the steroid ferrocene conjugates. The new compounds were obtained in good yield and were characterized by (1)H and (13)C NMR, IR. MS and elemental analysis. (C) 2011 Elsevier Inc. All rights reserved.
on the structure of the acyl azides, consecutive hydrolysis toward corresponding primary amides was observed. ‘Direct’ aminocarbonylation of the same iodoalkenes was also carried out by using ammonium carbamate as ammonia source under mild conditions. The α,β-unsaturated primary amides, formed in a chemoselective reaction, were isolated in good to excellent yields.
A new method for the synthesis of primary amides from alkenyl iodides in one carbonylation step using ammonium carbamate as ammonia synthon is reported. The products were obtained in good yields under mild reaction conditions using CO (1-6 bar). Steroidal substrates with various moieties (e.g., 6-OH group, lactams, or aromatic A-ring) could be converted selectively into the products.
报道了一种使用氨基甲酸铵作为氨合成子在羰基化步骤中由链烯基碘合成伯酰胺的新方法。使用 CO (1-6 bar) 在温和的反应条件下以良好的收率获得产物。具有各种部分(例如,6-OH 基团、内酰胺或芳族 A 环)的甾体底物可以选择性地转化为产物。
Synthesis of steroid–ferrocene conjugates of steroidal 17-carboxamides via a palladium-catalyzed aminocarbonylation – Copper-catalyzed azide–alkyne cycloaddition reaction sequence
Steroids with the 17-iodo-16-ene functionality were converted to ferrocene labeled steroidal 17-carboxamides via a two step reaction sequence. The first step involved the palladium-catalyzed aminocarbonylation of the alkenyl iodides with prop-2-yn-1-amine as the nucleophile in the presence of the Pd(OAc)(2)/ PPh(3) catalyst system. In the second step, the product N-(prop-2-ynyl)-carboxamides underwent a facile azide-alkyne cycloaddition with ferrocenyl azides in the presence of CuSO(4)/sodium ascorbate to produce the steroid ferrocene conjugates. The new compounds were obtained in good yield and were characterized by (1)H and (13)C NMR, IR. MS and elemental analysis. (C) 2011 Elsevier Inc. All rights reserved.