Synthesis and properties of (thieno[2,3-b]pyridin-3-yl) iminotriphenylphosphoranes. Molecular structure of (2-benzoyl-4-methoxymethyl-6- methylthieno[2,3-b]pyridin-3-yl)iminotriphenylphosphorane

Iminophosphoranes containing a thieno[2,3-b]pyridine fragment were obtained through a sequence of reactions: 1) alkylation of 3-cyano-2(1H)-pyridinethiones in alkaline medium by an α-halocarbonyl compound with subsequent Thorpe-Ziegler cyclization of the resultant 2-thioalkylpyridines to give 3-aminothieno[2,3-b]pyridines, 2) diazotization of the amino group and nucleophilic substitution of the diazonium group by an azido group without isolation of the diazonium salts, and 3) reaction of the 3-azidothieno[2,3-b] pyridines with triphenylphosphine. ©2004 Springer Science+Business Media, Inc.