The cyanocarbonyl group: Synthesis and crystal structure of an imidazole carbonyl cyanide, C12N5OH17

Article abstract of DOI:10.1023/A:1023200307429

1-t-Butyl-5-N-(dimethylaminomethylene)aminoimidazole-4-carbonyl cyanide (BUNDAMIC) is the first acyl cyanide to be synthesized from an imidazole-4-carboxylic acid, diethylphosphorocyanidate, and triethylamine and its structure determined by x-ray crystallography It crystallizes with four molecules in the monoclinic space group C(Combining low line)2/m(Combining low line) with a = 17.824(2), b = 6.784(2), c = 11.039(2) A, and β = 96.17(1)°; R(Combining low line) = 0.036 over 1086 unique x-ray reflections. The cyanocarbonyl group is nearly linear, C-C ≡ N angle 174.4(3)°, with dimensions C ≡ N, 1.137(3); C-C, 1.493(3); and C = O, 1.224(3) A. The imidazole ring, in the mirror plane, has a lengthened C4 = C5 bond of 1.421(3) A, and there is a short ring-closing approach, H...O6 = 2.07 A, between the methyleneamino hydrogen and the carbonyl oxygen.