Table 1.

List of substitutions for different derivatives.

Compounds	R	R′	M.p. (°C)	Overall yield (%)
5a	Phenyl	H	224–226	80
5b	Phenyl	Cl	254–258	84
5c	Phenyl	OH	246–248	76
5d	Phenyl	NO2	241–245	79
5e	Phenyl	OCH3	252–253	68
5f	Phenyl-4-NO2	H	254–255	79
5g	Phenyl-4-NO2	Cl	257–259	76
5h	Phenyl-4-NO2	OH	259–260	86
5i	Phenyl-4-NO2	NO2	258–260	84
5j	Phenyl-4-NO2	OCH3	248–250	75
5k	Pyridin-2yl	H	236–237	74
5l	Pyridin-2yl	Cl	238–240	82
5m	Pyridin-2yl	OH	258–259	72
5n	Pyridin-2yl	NO2	264–267	69
5o	Pyridin-2yl	OCH3	257–259	78