Functionalized 2-Hydrazinobenzothiazole with Isatin and Some Carbohydrates under Conventional and Ultrasound Methods and Their Biological Activities

Several chemical reactions were carried out on 3‐(benzothiazol‐2‐yl‐hydrazono)‐1,3‐dihydro‐indol‐2‐one (2). 3‐(Benzothiazol‐2‐yl‐hydrazono)‐1‐alkyl‐1,3‐dihydro‐indol‐2‐one 3a, 3b, 3c have been achieved. Reaction of compound 2 with ethyl bromoacetate in the presence of K2CO3 resulted the uncyclized product 4. Reaction of compound 2 with benzoyl chloride afforded dibenzoyl derivative 5. Compound 2 was smoothly acetylated by acetic anhydride in pyridine to give diacetyl derivative 6b. Moreover, when compound 4 reacted with methyl hydrazine, it yielded dihydrazide derivative 7, whereas the hydrazinolysis of this compound with hydrazine hydrate gave the monohydrazide derivative 8. {N‐(Benzothiazol‐2‐yl‐N′‐(3‐oxo‐3,4‐dihydro‐2H‐1,2,4‐triaza‐fluoren‐9‐ylidene)hydrazino]‐acetic acid ethyl ester (9) was prepared by ring closure of compound 8 by the action of glacial acetic acid. In addition, the reaction of 2‐hydrazinobenzothiazole (1) with d‐glucose and d‐arabinose in the presence of acetic acid yielded the hydrazones 10a,10b, respectively. Acetylation of compound 10b gave compound 11b. On the other hand, compound 13 was obtained by the reaction of compound 1 with gama‐d‐galactolactone (12). Acetylation of compound 13 with acetic anhydride in pyridin gave the corresponding N1‐acetyl‐N2‐(benzothiazolyl)‐2‐yl)‐2,3,4,5,6‐penta‐O‐acetyl‐d‐galacto‐hydrazide (14). Better yields and shorter reaction times were achieved using ultrasound irradiation. The structural investigation of the new compounds is based on chemical and spectroscopic evidence. Some selected derivatives were studied for their antimicrobial and antiviral activities.