EFFICIENT SYNTHESIS OF 2-AMINO-4-(2-CHLORO-5-(4- SUBSTITUTEDPHENYL) PYRIDIN-3-YL)-1-(4-SUBSTITUTED PHENYL)-7,7-DISUBSTITUTED-5-OXO-1,4,5,6,7,8- HEXAHYDROQUINOLINE-3-CARBONITRILE DERIVATIVES AND THEIR MICROBIAL SCREENING