Poorly reactive 5-piperazin-1-yl-1,3,4-thiadiazol-2-amines rendered as valid substrates for Groebke–Blackburn type multi-component reaction with aldehydes and isocyanides using TMSCl as a promoter

N-Substituted 5-piperazin-1-yl-1,3,4-thiadiazol-2-amines that fail to undergo Groebke–Blackburn type MCR with aldehydes and isocyanides provide fair to good yields of the respective 2-piperazin-1-ylimidazo[2,1-b][1,3,4]thiadiazoles when such reaction is promoted by an equimolar quantity of trimethylsilyl chloride in aprotic medium. These findings further extend the utility of TMSCl as the isocyanide-based MCR promoter, and also demonstrate that this silicon Lewis acid is the actual promoter of the reaction.