Synthesis And Structural Characterization Of Pyrrolidthione Derivatives

Natural cyclic tetrapyrroles, which involve porphyrins, chlorins, bacteriochlorins, isobacteriochlorins, higher saturated hydroporphyrins and corrins, belong to a kind of living substances with manifold biofunctions. The research on their synthesis and application is presently an important study content and hotspots of the chemistry of natural products. In this dissertation, the basis of "3+1" method to synthesize the cyclic tetrapyrroles was summarized through the analysis and comparison to various synthesis methods of chlorins, and the design principle and trend of the photosynthesis model systems and the new generation photosensitizers were proposed on the basis of the analysis to the acting process and mechanism of the photosynthesis and photodynamic therapy. The total synthesis ways of the chlorin model, chlorophyll a (belongs to chlorins) and the tolyporphin model (belongs to bacteriochlorins) were designed according to the "3+1" synthesis method. The synthesis of several pyrrolidthione derivatives were studied, such asthe ring-A building block of the chlorin model-2-cyano-2,3,3-trimethyl-5-thioxo-pyrrolidine, the ring-D building block of chlorophyll a-2-cyano-2,3-dimethyl-3-(N-benzyl-methanamido) oxymethyl-4-(2'-methoxy- carbonyl) ethyl-5-thioxo- pyrrolidineand the ring-A building block of the tolyporphin model-2-cyano-2,3-dimethyl-3-methoxycarbonylmethyl-5-thioxo-pyrrolidine. The structures of the synthetic products were characterized by elemental analysis, ultraviolet-visible (UV-vis), infrared (IR), 1H and 13C nuclear magnetic resonance (NMR) and mass spectra (MS).The results came to the following conclusions: the structures and performance indexes of the products conformed to the design requirement, the synthesis ways of the target compounds were brief and had good selectivity; the synthesis way of the ring-A building block of the chlorin model possessed very high practical value, for it was composed of only six step reactions and the yield of every reaction reached more than 80%; the tolyporphin model reflected the structural characteristic of natural tolyporphin compounds and the synthesis design of its ring-A building block was novel, practical and effective.