Portalone Gustavo, Colapietro Marcello
Chemistry Department, Sapienza University of Rome, P.le A. Moro 5, I-00185 Rome, Italy.
Acta Crystallogr C. 2007 Nov;63(Pt 11):o650-4. doi: 10.1107/S0108270107045659. Epub 2007 Oct 13.
The asymmetric unit of the amino-oxo tautomer of 5-formyluracil (systematic name: 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carbaldehyde), C(5)H(4)N(2)O(3), comprises one planar amino-oxo tautomer, as every atom in the structure lies on a crystallographic mirror plane. At variance with all the previously reported small-molecule crystal structures containing the 5-formyluracil residue, the formyl substituent in the title compound exhibits an unusual syn conformation. The molecules are linked into planar sheets parallel to the bc plane by a combination of six N-H...O and C-H...O hydrogen bonds. Four of the hydrogen bonds are utilized to stabilize the formyl group in the syn conformation.
5-甲酰基尿嘧啶（系统命名：2,4-二氧代-1,2,3,4-四氢嘧啶-5-甲醛）氨基-氧代互变异构体的不对称单元，化学式为C(5)H(4)N(2)O(3)，包含一个平面氨基-氧代互变异构体，因为结构中的每个原子都位于一个晶体学镜面平面上。与之前报道的所有含有5-甲酰基尿嘧啶残基的小分子晶体结构不同，标题化合物中的甲酰基取代基呈现出一种不寻常的顺式构象。分子通过六个N-H...O和C-H...O氢键的组合连接成平行于bc平面的平面片层。其中四个氢键用于稳定顺式构象中的甲酰基。
