An Efficient Sonochemical Synthesis of Novel Schiff’s Bases, Thiazolidine, and Pyrazolidine Incorporating 1,8-Naphthyridine Moiety and Their Cytotoxic Activity against HePG2 Cell Lines

Table 2

Synthesis of 4-oxothiazolidine derivatives (7a–d) under catalyzed ultrasonic irradiation, uncatalyzed ultrasonic irradiation, and using the conventional method.

Compound 7	Catalyzed ultrasonic irradiation		Uncatalyzed ultrasonic irradiation		Conventional
	Time (min)	Yield %	Time (min)	Yield %	Time (h)	Yield %
a	40	90	100	43	36	40
b	60	89	100	51	44	43
c	40	93	85	47	48	44
d	65	92	90	56	39	49