N-aryl/heteryl acetoacetamides are the intermediates used in the synthesis of various heterocyclic compounds like 1,4-dihydropyridines, pyrimidines etc. Three different substituted N-aryl/heteryl acetoacetamide derivatives (I-III) have been prepared from the reaction of ethylacetoacetate and three different aryl/heteryl primary amines under solvent free conditions using potassium tert-butoxide as catalyst. The reactions were carried out by two different methods (viz., Conventional and Microwave irradiation) and they are simple, eco-friendly and economical. All reactions were processed for optimization with different ratios of aryl/heteryl amine and ethylacetoacetate like1:1,1:1.2,1:1.4,1:1.6,1:1.8,1:2 and a comparison was made between the percentage yields with each ratio. Highest percentage yield was observed with 1:1.8 ratio for I & II and 1:1.6 ratio for III in both the methods. However, the microwave irradiation method was found to be superior to the conventional method. The newly synthesized compounds have been purified by recrystallization and characterized by physical and spectral data.DOI: http://dx.doi.org/10.3329/icpj.v2i11.16533 International Current Pharmaceutical Journal, October 2013, 2(11): 189-192

Two series of new symmetrical 4-aryl-2,6-dimethyl-3,5-bis-N-(aryl/heteroaryl)-carbamoyl-1,4-dihydropyridines (4a-f) and asymmetrical 4-aryl-2,6-dimethyl-3-N-(aryl/hetero-aryl)-carbamoyl-5-ethyl carboxylate-1,4-dihydro-pyridines (5a-f) have been synthesized by simple, economical and eco-friendly, modified Hantzsch reaction using                               N-aryl/heteroarylacetoacetamides (3a-c), ethylaceto-acetate (for asymmetric),  arylaldehydes and urea in presence of catalytic amounts of LiBr/Iodine and by microwave irradiation methods. The newly synthesized compounds were characterized by physical and spectral data, and evaluated for their possible in vitro MDR reversal activity by everted sac method using verapamil as standard P-gp inhibitor and domperidone as the standard P-gp substrate. Amongst the compounds tested, compound 4f exhibited the highest in vitro P-gp inhibitory activity. It was found to be more potent than the standard verapamil.