65267-32-5Relevant articles and documents
SYNTHESIS AND REARRANGEMENTS OF IMIDAZOLO- AND TRIAZOLO-DIAZINES
Khadem, H. S. El,Kawai, J.,Swartz, D. L.
, p. 239 - 248 (2007/10/02)
3-Methylimidazolopyridine and 3-methyl-1,2,4-triazolopyrazine were prepared by coupling ethyl dithioacetate with 2-(aminomethyl)pyridine and 2-hydrazinopyrazine, respectively.Both compounds are stable in dilute acids and bases, unlike 3-methyl-1,2,4-triazolopyrimidine obtained by coupling the same dithioacetate with 2-hydrazinopyrimidine, which quickly undergoes a Dimroth type rearrangement.Coupling ethyl dithioacetate with 2-hydrazino-4-hydroxy-6-methylpyrimidine yielded a mixture of 3,5-dimethyl-1,2,4-triazolo-7(8H)-pyrimidone and 3,7-dimethyl-1,2,4-triazolo-5(8H)-pyrimidone, which were identified by 2D nmr.The last compound underwent a Dimroth rearrangement with acids to yield 2,5-dimethyl-1,2,4-triazolo-7(4H)-pyrimidone, whereas the first did not.Finally, coupling ethyl dithioacetate with 5-chloro-4-hydrazinopyrimidine afforded 8-chloro-3-methyl-1,2,4-triazolopyrimidine, which upon treatment with acids underwent a reversible ring opening to afford 2-chloro-1-formamido-2-(5-methyl-1,3,4-triazolo-2-yl)ethene.The latter on pyrolysis gave the starting base without undergoing rearrangement.
