Cross-coupling of copper arylacetylides with N-(o-iodoaryl)hydrazines as a new method of synthesising 2-substituted indoles

Thermal Cyclization of (2-Ethynylphenyl)triazenes: Facile Synthesis of Substituted Cinnolines and Isoindazoles

“…Some thermal rearrangements have been reported, but they require either the presence of an activated methyl carbon ortho to the nitrogen functionality or a good leaving group to generate the N−aryl bond. Still other groups have used alkyne precursors for indazole synthesis, although the more reactive azide is necessary for cyclization.…”

A directive effect of heterofunctions in cyclocondensation reactions of acetylenylquinones with hydrazine

“…a hydroxyl group, in the acetylenic substituent; this directive effect was used for the synthesis of naphtho [2,3-h]cinnoline-4,7,12-trione and 4H-naphtho[1,8-cd]-1,2diazepin-8-one derivatives.Acetylenic derivatives of cinnoline and benzene with a labile chlorine atom at the ortho position react with hydrazine to close a pyrazole ring. [1][2][3] When continuing our studies of the heterocyclization of acetylenylquinones, 4-9 we carried out this condensation in the anthraquinone series.In 2-acetylenyl-1-chloro-9,10-anthraquinones 1, the halogen atom is readily substituted by nucleophilic groups, 10 and the triple bond activated by the quinone nucleus is efficiently attacked by N-nucleophiles. 11 This attack is directed onto the β-C atom of the triple bond.…”

“…Therefore, we supposed that the cyclocondensation of 1 with NH 2 NH 2 will result in the formation of a six-membered diazine ring rather than a five-membered diazole ring as in the above reactions. [1][2][3] In addition, competitive heterocyclization with the participation of the peri-carbonyl group can play a noticeable role.We found that anthraquinones 1 easily condense with NH 2 NH 2 (pyridine, 90-115 °C). Compounds 1a,b with no heteroatomic groups in their acetylenic substituents are transformed to only pyrazole derivatives.…”

“…Acetylenic derivatives of cinnoline and benzene with a labile chlorine atom at the ortho position react with hydrazine to close a pyrazole ring. [1][2][3] When continuing our studies of the heterocyclization of acetylenylquinones, 4-9 we carried out this condensation in the anthraquinone series.…”

“…Therefore, we supposed that the cyclocondensation of 1 with NH 2 NH 2 will result in the formation of a six-membered diazine ring rather than a five-membered diazole ring as in the above reactions. [1][2][3] In addition, competitive heterocyclization with the participation of the peri-carbonyl group can play a noticeable role.…”