Alkylation of Rhodium Porphyrins Using Ammonium and Quinolinium Salts
摘要:
Alkylation of rhodium(III) porphyrins [Rh-II(por)] was achieved under relatively mild conditions in up to 98% yields, where readily available ammonium and quinolinium salts were utilized as the alkylating agents. This transformation tolerates air and water, thus serving as a convenient method to prepare a variety of alkyl- and benzyl-Rh-III(por) complexes. Preliminary mechanistic studies support an S(N)2-like reaction pathway involving a Rh-I(por) anion intermediate.
Alkyl transfer from quaternary ammonium salts to cobalt (I): Model for the cobalamin-dependent methionine synthase reaction
作者:Ellen Hilhorst、Atef S. Iskander、Tjoe B.R.A. Chen、Upendra K. Pandit
DOI:10.1016/s0040-4020(01)85359-x
日期:1994.1
The reaction of cobaloxime(I) with diverse quaternaryammoniumsalts leads, in general, to a group transfer from nitrogen to cobalt. The behaviour of the salts in these transalkylations is consistent with an SN2 mechanism, involving Co(I) as a nucleophile. In a model study of the cobalamin-dependent methionine synthase reaction, 5-13CH3-methyl labelled 5,5,6,7-tetramethyl-5,6.7,8-tetrahydropteridinium
钴肟(I)与各种季铵盐的反应通常导致基团从氮转移到钴。盐在这些烷基转移反应中的行为与S N 2机理一致,涉及Co(I)作为亲核试剂。在钴胺素依赖性蛋氨酸合酶反应的模型研究中,以5- 13 CH 3-甲基标记的5,5,6,7-四甲基-5,6.7,8-四氢idi啶鎓盐(23)-天然辅酶5的模型使-CH 3 H 4-叶酸(1)-与钴肟(I)和钴胺素(I)反应。在每种情况下,通过13 C-NMR光谱。