Diazopropyne, reaction with acetylene

The first representative of the acetylenic derivatives, 3(5)-ethynylpyrazole, was obtained by condensation of diacetylene with diazomethane by Kuhn and Henkel (41LA279) and later by other authors (69IZV2546), and by reaction of acetylene with diazopropyne (62AG252 68LA113) (Scheme 2). 

Diazopropyne reacts similarly with a monosubstituted acetylene to form 3(5)-alkynylpyrazoles (68LA113). Thus, the reaction of diazopropyne with acetylene-carboxylic acid methyl ether results in 5-ethynyl-l//-pyrazole-3-carboxylic acid methyl ether in 48 h in 62% yield. 5-Ethynyl-l//-pyrazole-3,4-dicarboxylic acid dimethyl ester was prepared by reaction of diazopropyne with acetylenedicar-boxylic acid methyl ether (Scheme 10). 

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See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

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