Table 3. Derivatives of Series 8 Synthesized with Various Aldehydes along with Obtained Results.

entry	producta	R	yieldb (%)	Rf value	melting point (°C)
1	8a	C6H5	67	0.76	158–15943,48
2	8b	4-NO2-C6H4	74	0.53	172–173
3	8c	4-Me-C6H4	69	0.72	148–150
4	8d	4-OMe-C6H4	66	0.67	156–157
5	8e	2-OH-C6H4	71	0.61	176–178
6	8f	3-NO2-C6H4	70	0.57	167–16842
7	8g	4-OH, 3-OCH3 C6H3	70	0.48	181–182
8	8h	C6H4-CH=CH	66	0.65	164–165
9	8i	2-pyridinyl	42	0.61	145–148
10	8j	2-furyl	76	0.69	147–149
11	8k	2-thiophenyl	74	0.66	151–152

^aProducts were characterized with standard and reliable spectral techniques.

^bYield refers to the total extraction from different crops.