Synthesis of some Fused Heterocyclic Compounds for Pharmacologicl Study

Heterocyclic Compounds-Enaminoester-nitrile analogues.This thesis comprises a general review of the detailed chem¬istry of -enamino ester and their nitrile analogues as early appeared in the literature. In addition, some novel condensed heterocyclic .compounds of potential biological activity derived from -enamino esters and their nitrile analogues have been described. Moreover, this work provides few new chemical aspects in the chemistry of nitriles for instance :g:A) In Michael addition reaction, each type of Michael adduct is trapped only within a specific temperature channel beyond which it suffers retro-Michael type reaction to give unexpected reaction pathway.B) Trapping of Michael adduct is a matter of polarity as well as boiling point of the medium used (temperature).C) The Michael adducts that come out from addition of nucelophiles to benzylidene malonodinitrile are generally more stable than those obtained from addition to benzylidene ethyl cyanoacetate and hence are trapped at relatively higher temperature.D) In the reaction of aldehydes with 5,5-dimethyl-1,3-cyclohexane-dione (dimedone), only 2,4-dichlorobenzaldehyde beahves anomolouslyto react in 1 : 1 ratio, which could be accounted for the relativeuir ljbill Ly ul Miuhuul jdduel cind liencu i lu mure retictlun withthe excess of cyclic 1,3-dione to give the corresponding xanthenes.E) This work also, provides a good chemical peice which is the acid catalysed hydrolysis of £3-enarnino nitriles fused to pyran moiety into their corresponding lactonecarboxylic acids contrasting its behaviour toward -enamino nitriles fused to 1,4-dihyDROPyridine moiety which give pyridopyrimidones