A Convenient Synthesis of Ethyl 1-Amino-3-(Substituted Phenyl)-2-Cyano-3H-Benzo[4,5]Thiazolo-[3,2-a] Pyridine-4-Carboxylate Derivatives and Some of Their Reactions: Scientific Explanation

The presented compounds were createdby interaction of ethyl 2-(benzo[d]thazol-2-yl)acetate (3) with different arylidinemalononitrile derivatives (4a-c) in EtOH/TEA solution at room temperature. When 3 was treated with 2- (ethoxymethylene)-malononitrile (4f) under same reaction conditions, the ethyl iminothiazolopyridine-4-carboxylate (6) was obtained. Ethyl (amino(methoxy)methyl)-3-(substitutedphenyl)-1-oxo-1H-benzo[4,5]thiazole[3,2-a]pyridine-4- carboxylate (8a,b) was obtained on the basis of reaction of 3 with different cyanoacrylate derivatives (7a,b) in MeOH/TEA at room temperature, while the diethyl thiazolo[3,2-a]pyridine-4-carboxylate derivative (8c) was obtained under the same conditions of reaction. The amino-imino derivative (10) was also fully prepared and used to synthesis new pyrido[3,2- e][1,2,4]triaziolo[1,5-c]pyrimidine-5-carboxylate derivatives  (12).  All of the newly synthesised compounds' structures were confirmed using elemental analysis and spectroscopic data. The triazolo[1,5-c]pyrimidine-5-carboxylate derivatives (12a-c) were obtained when 10a was reacted with electrophilic reagents.