Synthesis and characterization of novel mono- and dicarboxyalkylthiacarbocyanines and their ester derivatives

Several novel asymmetric N-carboxyalkyl-N′-alkylthiacarbocyanines, symmetric N,N′-dicarboxyalkylthiacarbocyanines and their methyl ester derivatives have been synthesized and fully characterized by 1H and 13C NMR, FTIR and visible spectroscopy and HRMS (FAB). Two different methods for the preparation of the asymmetric thiacarbocyanines have been used and discussed.