کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1409618 | 1501827 | 2011 | 12 صفحه PDF | دانلود رایگان |
Novel [1,2,4]-triazolo-[1,5-a]pyrimidine derivatives were prepared by oxidative cyclization of suitable N-benzylidene-N′-pyrimidin-2-yl hydrazine precursors, followed by a Dimroth rearrangement. Reaction of 6-bromo-[1,2,4]-triazolo-[4,3-a]pyrimidines with aliphatic amines under microwave irradiation gave the unexpected 5-amino compounds from an ANRORC-type mechanism. Full NMR and HRMS characterization was done for all the obtained compounds. DFT calculations of absolute shielding permitted to predict 1H, 13C and 15N chemical shifts, which were in good agreement with the experimental ones. Theoretical studies at the B3LYP/6-311++G(d,p) level corroborated that [1,2,4]-triazolo-[1,5-a]pyrimidines were more stable than their [4,3-a] counterparts.
Journal: Journal of Molecular Structure - Volume 987, Issues 1–3, 22 February 2011, Pages 13–24