Microwave-Assisted Synthesis of<i>s</i>-Triazino[2,1-<i>b</i>][1,3]benzoxazoles,<i>s</i>-Triazino[2,1-<i>b</i>][1,3]benzothiazoles, and<i>s</i>-Triazino[1,2-<i>a</i>]benzimidazoles
作者:Wai-Keung Chui、Anton V. Dolzhenko、Anna V. Dolzhenko
DOI:10.1055/s-2006-926290
日期:——
2-Amino-4-oxo-derivatives of s-triazino[2,1-b][1,3]benzoxazoles, s-triazino[2,1-b][1,3]benzothiazoles, and s-triazino[1,2-a]benzimidazoles were synthesized by carbonylation of 2-benzoxazolylguanidines, 2-benzothiazolylguanidines, and 2-benzimidazolylguanidines with phenyl isocyanate under microwave irradiation (180 °C, 15 minutes). Using phenyl isothiocyanate instead of phenyl isocyanate under the same conditions led to the successful ring closure via thiocarbonylation of 2-benzoxazolylguanidines. However, the formation of 2-imino-4-phenylimino-s-triazino[2,1-b][1,3]benzothiazoles from 2-benzothiazolylguanidines was observed instead under microwave irradiation conditions.
通过在微波辐照下(180 °C,15分钟)将2-苯并噁唑基胍、2-苯并噻唑基胍和2-苯并咪唑基胍与苯基异氰酸酯进行羰基化反应,合成了2-氨基-4-氧代s-triazino[2,1-b][1,3]苯并噁唑衍生物、s-triazino[2,1-b][1,3]苯并噻唑衍生物和s-triazino[1,2-a]苯并咪唑衍生物。在相同条件下,使用苯基异硫氰酸酯代替苯基异氰酸酯时,成功地实现了2-苯并噁唑基胍的环合闭合反应,形成硫羰基化产物。然而,在微波辐照条件下,从2-苯并噻唑基胍观察到了2-亚氨基-4-苯亚氨基s-triazino[2,1-b][1,3]苯并噻唑的形成。