An Efficient, Clean, and Catalyst-Free Synthesis of Fused Pyrimidines Using Sonochemistry

Table 3

Synthesis of pyrimido[4,5-b]quinoline 6a–f.

Entry	Product	Ar	Time (min)	Yield (%)^a
1	6a	4-FC6H4	10 (180)^b	95 (90)^b
2	6b	1-naphtyl	15 (230)^b	93 (87)^b
3	6c	4-CH3C6H4	20 (270)^b	89 (82)^b
4	6d	4-CH3OC6H4	23	87
5	6e	5-methylthiophen-2-yl	25	82
6	6f	4-ClC6H4	17	90

Isolated yields.
^bConventional conditions.