The generalized anomeric effect in the 1,3-thiazolidines: Evidence for both sulphur and nitrogen as electron donors. Crystal structures of various N-acylthiazolidines including mercury(II) complexes. Possible relevance to penicillin action
作者:Sosale Chandrasekhar、Deepak Chopra、Kovuru Gopalaiah、Tayur N. Guru Row
DOI:10.1016/j.molstruc.2006.10.034
日期:2007.6
nitrogen-to-sulphur and sulphur-to-nitrogen GAE's operate simultaneously in the 1,3-thiazolidines, the former being dominant. (This is analogous to the normal and exo-anomeric effects in pyranoses, and also leads to an interesting application of Baldwin's rules.) The nitrogen-to-sulphur GAE is generally enhanced in the mercury(II) complexes (presumably via coordination at the sulphur); a 'competition' between the GAE
在 N-(4-硝基苯甲酰基)-1,3-噻唑烷和 N-酰基-1,3-噻唑烷的晶体结构中寻找了 N-酰基-1,3-噻唑烷中的广义异头效应 (GAE) 的证据,这是青霉素中的一个重要结构基序。其 (2:1) 与氯化汞、N-乙酰基-2-苯基-1,3-噻唑烷和 N-苯甲酰基-1,3-噻唑烷与溴化汞的 (2:1) 络合物。之间通常观察到相反的关系。噻唑烷环的 C-2-N 和 C-2-S 键长,支持 GAE 的存在。(最大键长变化对于 C-2-N-3、S-1-C-2 类似于 0.04 埃,对于 N-3-C-6 类似于 0.08 埃。)与 N-酰基吡咯烷和四氢噻吩的比较表明氮-硫和硫-氮 GAE 在 1,3-噻唑烷中同时运行,前者占主导地位。(这类似于吡喃糖中的正常和外异头效应,也导致了鲍德温规则的有趣应用。)汞(II)配合物中的氮硫 GAE 通常增强(大概是通过在硫); GAE 和 N-酰基部分的酰