Synthesis, Characterization and Evaluation of Analgesic and Anti-Inflammatory Activities of Some Novel 6-(Indol-2-Yl)-Pyrimidine-2-Amines

Non steroidal anti-inflammatory agents (NSAIDs) continue to be one of the most widely used groups of therapeutic agents. NSAIDs cause several serious adverse effects; the most important one is gastric injury that might later cause gastric ulceration and renal injury. Thus attempts to develop NSAIDs that are devoid of classical NSAIDs toxicity continues. Synthesis and pharmacological screening of various derivatives of 6-(indol-2-yl)-pyrimidine-2-amines viz 4-(4-substitutedphenyl)-6-(3-phenyl-1-tosyl-1H-indol-2-yl) pyrimidin-2-amine and 4-(4-substitutedphenyl)-6-(1- (methylsulfonyl)-3-phenyl-1H-indol-2-yl) pyrimidin-2-amine (6a-6l) is reported here. The compounds (6a-6l) were synthesized by cyclization of (E)-3-(4-sunstitutedphenyl)-1-(1-(substitutedsulfonyl)-3-phenyl-1H-indol-2-yl) prop-2- en-1-one with guanidine hydrochloride in presence of sodium isopropoxide. The structures were confirmed by FT IR, ¹H NMR and elemental analysis. These compounds were investigated for their analgesic, inflammatory and ulcerogenic activities. Most of the compounds tested (6a-6l) showed analgesic and inflammatory activities with very less ulcerogenic action. The compound 2-(5-(4-chlorophenyl)-1-phenyl-4, 5-dihydro-1H-pyrazol-3-yl)-1- (methylsulfonyl)-3-phenyl-1H-indole (6b) was the most active compound in the series. The results showed that the incorporation of appropriately substituted pyrimidine ring in indole nucleus can afford good analgesic and anti inflammatory activities with reduced gastric irritation to the compounds.