title: Modified guanidines as potential chiral superbases. 2. Preparation Of 1,3-unsubstituted and 1-substituted 2-iminoimidazolidine derivatives and a related guanidine by the 2-chloro-1, 3-dimethylimidazolinium chloride-induced cyclization of thioureas
abstract: Simple preparation methods for modified guanidines were explored for new chiral superbases. Thus, (4S,5S)-4,5-diphenyl- and diastereomeric cyclohexane-fused 2-iminoimidazolidines were prepared from (1S,2S)-1,2-diphenylethylenediamine and (1R,2R)- or (1S,2S)-1, 2-diaminocyclohexanes through cyclization of protected thiourea intermediates with 2-chloro-1,3-dimethylimidazolinium chloride (DMC) as a key reaction. In the (4S,5S)-4,5-diphenyl series 1-methyl-2-iminoimidazolidines and 2-diethylaminoimidazoline were also prepared as related guanidines.
authors.affiliation: Faculty of Pharmaceutical Sciences and Chemical Analysis Center, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan, and Central Research Laboratory, Shiratori Pharmaceutical Co. Ltd., 6-11-24 Tsudanuma, Narashino, Chiba 275-0016,
authors.initials: T
authors.lastname: Isobe
authors.initials: K
authors.lastname: Fukuda
authors.initials: T
authors.lastname: Tokunaga
authors.initials: H
authors.lastname: Seki
authors.initials: K
authors.lastname: Yamaguchi
authors.initials: T
authors.lastname: Ishikawa