T. Masquelin, D. Sprenger, Roman Baer
1998
Citations
0
Influential Citations
32
Citations
Journal
Helvetica Chimica Acta
Abstract
A novel general synthesis of 2,4,5-tri- and 2,4,5,6-tetrasubstituted pyrimidines 5a–d and 7a, e, f, g by condensation of thiouronium salts of type 3 with (ethoxymethylidene)malononitrile (4) and [bis(methylthio)methylidene]malononitrile (6), respectively, was first established in solution (Scheme 1) and successfully transferred onto solid support by using the polymer-bound thiouronium salt 11 (Scheme 3). Further investigations were directed toward a multidirectional cleavage procedure of the 2-(alkylsulfinyl) intermediates, obtained from the 2-(alkylthio)pyrimidines 7a (Scheme 2) or 12 and 14 (Schemes 3 and 4), with different nucleophiles to form highly substituted pyrimidines. In addition, fused-heterocycle derivatives 22a--h, 24a–c, and 26a–e were generated in good-to-excellent yields by condensation of 7a, e, h with versatile isocyanates and isothiocyanates, with subsequent alkylation (Scheme 5).