Cinnoline—continued

CnHuNjOj (Continuation) Cinnoline 4-Ethyl-3-methyl-8-nitro-E9a, 715 (H - N02)... 

Cinnolines are another relatively unfamiliar class of heterocycle. A synthesis employing tandem C—N bond formations has recently been reported by the Willis research group. Continuing their use of key 2-(2-haloalkenyl)aryl halide substrates, they demonstrated that when combined with diethyl hydrazine-1,2-dicarboxylate, these substrates could undergo tandem copper-catalyzed alkenylation and arylation processes to generate novel diethyl dihydrocinnoline-l,2-dicarboxylates such as 56 [108]. These intermediates could be isolated and then treated with aqueous sodium hydroxide to reveal cinnoline products, such as 57, in moderate to excellent yields as shown in Scheme 24.28. Alternatively, the aromatic products could be revealed by treatment with sodium hydroxide in situ in a one-pot process. 

---