aN-Benzoyl-2-(trifluoromethyl) histamine has been transformed, via a difluorodiazafulvene intermediate, into 2-carboxy-and 2-(carbomethoxy) histamine. 2-Carboxy-~-histidine was prepared by a similar route. 2-(Carbomethoxy)-L-histidine was prepared by methanolysis of aN-(tert-butoxycarbonyl)-2-(trifluoromethy1)-L-histidine and acid hydrolysis of the intermediate ortho ester. 2-Cyanohistamine and 2-cyano-~-histidine are best prepared by ...
