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Benzamidines, alkamidines and formamidines formed by use of aryl‐ and alkyliminodimagnesium: Molar ratio and structure of reagent governing the reaction
Author(s) -
Okubo Masao,
Omote Yasumasa
Publication year - 1996
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199604)9:4<212::aid-poc775>3.0.co;2-a
Subject(s) - chemistry , reagent , aryl , alkyl , benzonitrile , organic chemistry , molar ratio , amidine , medicinal chemistry , catalysis
In order to extend the the method for preparation of amidines using N‐Mg reagents, aryl‐ and alkyliminodimagnesium [IDMg, ArN(MgBr) 2 and RN(MgBr) 2 ] were reacted with esters, amides, ortho‐ esters, acetals, aminoacetal and arene‐ and alkane carbonitriles. Among the compounds used, aminoacetal and carbonitriles were proved to be useful as starting materials for amidine preparation; alkyl‐IDMgs were successfully used for the first time. It was noted that an excess molar amount of IDMg is needed in the reported reaction of ArN(MgBr) 2 with benzonitrile (aryl‐aryl combination), whereas no excess is needed in aryl‐alkyl, alkyl‐aryl, and alkyl‐alkyl combinations of reagent and substrate. From the viewpoint previously proposed in terms of relative efficiency of single electron transfer in the reactions of magnesium reagents, the most probable reason for the difference in the need for an excess molar amount of aryl and alkyl IDMg was ascribed to the difference in the electron‐donating abilities of reagents. Additional minor reasons are discussed.