吡唑并[3,4- b ]吡啶和吡唑并[1,5- a ]嘧啶体系的区域选择性甲酰化反应,采用的是Vilsmeier-Haack条件
摘要:
吡唑并[3,4- b ]吡啶和吡唑并[1,5- a ]嘧啶通过Vilsmeier-Haack条件的反应中发现了区域选择性的甲酰化行为。虽然4,5-和6,7-二氢衍生物分别提供了吡唑并[3,4- b ]吡啶5-甲醛和4,7-二氢吡唑并[1,5 - a ]嘧啶3,6-二甲醛。芳族类似物仅产生吡唑并[1,5 - a ]嘧啶-3-甲醛,吡唑并吡啶衍生物没有反应。
2-(4-Chlorophenyl)-5-(4-nitrophenyl)-4,7-dihydropyrazolo[1,5-<i>a</i>]pyrimidine-3,6-dicarbaldehyde: a chain of rings built from N—H...O and C—H...O hydrogen bonds
作者:Jorge Trilleras、Jairo Quiroga、John N. Low、Justo Cobo、Christopher Glidewell
DOI:10.1107/s0108270108014509
日期:2008.6.15
In the title compound, C20H13ClN4O4, the six-membered heterocyclic ring is planar and the molecular dimensions provide evidence for polarization of the molecular-electronic structure. Molecules are linked into a chain of rings by a combination of N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds, but the nitro group does not participate in the supramolecular aggregation. This study illustrates the marked influence of peripheral substituents on the pattern of hydrogen-bonded aggregation in compounds of this type.