Dimethylglyoxime, reaction with acetylene

A cobaltphosphine complex (ClCo(PPh3)3) reacts with cyclobutenedione to afford a phthaloyl cobalt complex. As shown in eq. (17.33), the ligand is exchanged by adding dimethylglyoxime pyridine, and a quinone is obtained by reaction with acetylene [45,78,79]. 

The reaction of dimethylglyoxime, a simplest representative of 1,2-diketone dioximes, with acetylene in the system KOH/DMSO (100°C-140 C, initial acetylene pressure 14 atm), leads to the expected N,N -divinyl-2,2 -dipyrrole (15% yield), among other products isolated from the reaction mixture being 0-vinyl methylgly-oxime and 2-acetyl-N-vinylpyrrole (Scheme 1.75) [269]. Also, 2-(2-pyridyl)-N-vinyl-pyrrole has been unexpectedly identified (see Section 1.5.4). 

SCHEME 1.75 The reaction of dimethylglyoxime with acetylene in the system KOH/DMSO. 

The closing of the pyridinic cycle is observed in the reaction of dimethylglyoxime with acetylene (Scheme 1.157) [269]. Among the expected reaction products such as O-vinyl oxime, pyrrole, and dipyrrole, N-vinyl-2-[2 -(6 -methylpyridyl)]pyrrole has also been isolated from the reaction mixture, prepared under usual conditions (KOH/DMSO, 100°C-140°C). 

SCHEME 1.158 Transformations of intermediate O-vinyl oxime formed in the reaction of dimethylglyoxime with acetylene. 

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See also in sourсe #XX -- [ ]

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