“…Derivatives of [1,3]-dithiolo [4,5-b]quinoxaline 121 and 122 were synthesized from α-acetylenic ketones and 2,3-quinoxalinedithiol (A. S. Nakhmanovich, G. G. Skvortsova, et al) [326]. An effective method for the production of the analogous unsubstituted heterocycles 125 is intramolecular nucleophilic cyclization of dicarbofunctional silanes 126 [329,330].…”