We report herein the synthesis of β-2-benzimidazolyl- and β-2-indolyl-C-nucleosides and their α-anomers in a stereoselective way. The stereocontrol was observed either in the reduction step (hemiacetal to diol) of the protected heterocycles (1b–d), or in the intramolecular Mitsunobu cyclisation of the free heterocyclic diols obtained from the hemiacetals 1a and 1e.
Photographic processing compositions including hydrophobically modified thickening agent
申请人:POLAROID CORPORATION
公开号:EP0683430A2
公开(公告)日:1995-11-22
Photographic processing compositions comprising an aqueous alkaline medium and a hydrophobically modified thickening agent are disclosed. The subject thickening agent increases the viscosity of the processing composition while maintaining a relatively uniform homogenous mixture of the constituents thereof. The subject processing compositions are useful in photographic diffusion transfer film units and processes.
Efficient electrochemical cleavage of N,N-dimethylaminosulfonyl-protected indoles
作者:Martine Largeron、Brid Farrell、Jean-François Rousseau、Maurice-Bernard Fleury、Pierre Potier、Robert H Dodd
DOI:10.1016/s0040-4039(00)01504-5
日期:2000.12
Indoles protected at the N-1 position with the N,N-dimethylaminosulfonyl group were efficiently deprotected by electrolysis. Yields were in the 80-90% range and the method was compatible with a number of functional groups (nitrile, ester, chloride, carboxamide). (C) 2000 Elsevier Science Ltd. All rights reserved.
Ruthenium-Catalyzed Isomerization of <i>ortho</i>-Silylanilines to Their <i>para</i> Isomers
Stereocontrolled Synthesis of Heterocyclic C-Nucleosides. Protecting Group Effect and Molecular Modeling Studies
作者:Dominique Guianvarc'h、Jean-Louis Fourrey、Marie-Elise Tran Huu Dau、Vincent Guérineau、Rachid Benhida
DOI:10.1021/jo016345x
日期:2002.5.1
We report herein a short stereocontrolledsynthesis of heterocyclic C-nucleosides (indole, imidazole, benzimidazole, and 6-iodobenzimidazole). First, condensation of 2-lithiated heterocycles 2-5 with 5-(tert-butyldiphenylsilyl)-2,3-O-isopropylidene-D-gamma-ribonolactone (1) afforded the hemiacetals 6-9 in good yields. Then, borohydride reduction (NaBH(4)) of the protected hemiacetals proceeded stereoselectively