Stereoselective Synthesis and Antiviral Activity of (1 E ,2 Z ,3 E )‐1‐(Piperidin‐1‐yl)‐1‐(arylhydrazono)‐2‐[(benzoyl/benzothiazol‐ 2‐oyl)hydrazono]‐4‐(aryl 1 )but‐3‐enes

The reaction of benzoyl hydrazine 1a or benzothiazole‐2‐carbohydrazide 1b with 2‐oxo‐ N ‐arylpropanehydrazonoyl chlorides 2a–d yielded (1 Z ,2 E )‐2‐[(benzoyl/benzothiazol‐2‐oyl)hydrazono]‐ N ‐(aryl)propanehydrazonoyl chlorides 3a–e . The reaction of 3a–c with sodium benzenesulphinate furnished sulphones 5a–c while the reaction of 5d , e with hydroxyl amine afforded hydroxomoyl derivatives 6a , b . The one‐pot sterioselective reaction of N ‐(aryl)propanehydrazonoyl chlorides 3 with certain aromatic aldehydes in the presence of piperidine resulted in the formation of (1 E ,2 Z ,3 E )‐1‐(piperidin‐1‐yl)‐1‐(arylhydrazono)‐2‐[(benzoyl/benzothiazol‐2‐oyl)hydrazono]‐4‐(aryl 1 )‐but‐3‐enes 7a–g . X‐ray analysis of piperidinyl amidrazone 7g showed a conversion of its geometrical structure with respect to that of compound 3 and confirmed the stereoselectivity of the latter reaction. The piperidinyl amidrazones 7a–g possessed a significant antiviral activity against herpes simplex viruses (HSV‐1). Compound 7d reduced the number of viral plaques of herpes simplex type‐1 (HSV‐1) by 67%, with respect to the effect of reference drug Aphidicolin.