Table 1. The structure, melting point and yield of title compounds.

Comp.	The linking position	R1	R2	Appearance	Yield	Mp. (°C)
7a	2	H	H	white solid	63%	182–183
7b	3	H	H	yellow solid	68%	182–183
7c	4	H	H	white solid	72%	182–183
7d	4	OCH3	H	white solid	69%	240–241
8a	2	H	H	white solid	55%	169–170
8b	3	H	H	white solid	58%	171–172
8c	4	H	H	white solid	63%	169–170
8d	4	OCH3	H	white solid	67%	155–156
9a	2	H	H	gray solid	62%	208–209
9b	3	H	H	white solid	61%	209–210
9c	4	H	H	white solid	68%	208–209
9d	4	OCH3	H	white solid	63%	159–160
9e	2	H	CH3	brown solid	60%	186–187
9f	3	H	CH3	brown solid	67%	187–188
9g	4	H	CH3	brown solid	55%	187–188
9h	4	OCH3	CH3	brown solid	58%	197–198
9i	2	H	Cl	white solid	55%	170–171
9j	3	H	Cl	gray solid	53%	171–172
9k	4	H	Cl	gray solid	57%	170–171
9l	4	OCH3	Cl	white solid	47%	192–193