Synthesis and Reactions of Some New Heterocycles Containing Nitrogen and Sulphur of anticipated Biological Activity

Abstract

The present work aimed to utilize 4-Arylidene-2-phenyl-oxazol-5(4H)-one 29a,b in the synthesis of some new heterocycles of potent biological activity. In the present investigation we aimed to study the action of hydrazine hydrate on 4-Arylidene-2-phenyl-oxazol-5(4H)-one 29a,b under different conditions. The treatment of 29a,b with hydrazine hydrate in refluxing ethanol afforded the E-configurated isomers hydrazide derivative 165a,b. While, on carrying out the same reaction by stirring at room temperature on 29a in methanol with hydrazine hydrate we obtained the Z-configurated isomer of hydrazide derivative 166. However, refluxing 29b in methanol with hydrazine hydrate for 1h afforded the cyclic pyrazolidinone derivative 167. The authors aimed to utilize the hydrazide derivative Z-166 to synthesis some heterocycles of anticipated biological activity. Ring closure of hydrazide Z-166 using 1:1 mixture of hydrochloric and acetic acid afforded the Z-configurated isomer of 5-benzylidene-3-phenyl-1,2-dihydro-1,2,4-triazin-6(5H)-one 168, while refluxing Z-166 in 10% aqueous sodium hydroxide gave the 5-benzyl-3-phenyl-1,2,4-triazine-6(5H)-one 170 as a major product. Heating of hydrazide (Z)-166 with benzoyl chloride in dry benzene gave the E-configurated isomer of dibenzoyl hydrazide derivative N(2-benzoylhydrazinyl)-3-oxo-1-phenylprop-1-en-2-yl) benzamide (E)-171. The latter compound underwent cyclization with phosphorus oxychloride to give the five membered imidazolone derivative 173, while, when heated with 1:1 mixture of hydrochloric and acetic acid gave the six membered triazinone derivative 174.