Minoru Yagi

Formation of a chiral β-lactam by photocyclisation of an achiral oxo amide in its chiral crystalline state

Chiral crystals of the achiral oxo amide N,N-di-isopropylphenylglyoxylamide, prepared in large quantities, were irradiated in the solid state to give the optically active β-lactam 3-hydroxy-1-isopropyl-4,4-dimethyl-3-phenylazetidin-2-one in high optical and chemical yields.

Baeyer–Villiger reaction in the solid state

Some Baeyer–Villiger oxidations of ketones with m-chloroperbenzoic acid proceed much faster in the solid state than in solution.

New preparative and optical resolution method for β-lactams

Photoirradiation of a 1 : 1 inclusion compound of oxoamide and N,N,N′,N′-tetracyclohexylbiphenyl-2,2′-dicarboxamide in the solid state gave a β-lactam, which was resolved by complexation with optically active 9,9′-biphenanthryl-10,10′-diol. Chiral recognition of the host and guest in the inclusion compound was studied by X-ray crystallographic analysis.

Freezing of equilibrium of imidazoles by inclusion crystallization with a host compound: isolation of the different tautomeric types in a pure state

For each of the imidazole equilibrium tautomers mixtures, 2-phenyl-4(5)- and 2-ethyl-4(5)-methylimidazole, 2-phenyl-5- and 2-ethyl-5-imidazole isomers, respectively, were isolated, in a pure state by means of inclusion complexation with a host compound. In the case of 4(5)-methylimidazole, however, it was the pure 4-methylimidazole tautomer that was isolated as its inclusion complex with the rac-bis-β-naphthol host. In the latter case, it was found that (+)- and (−)-bis-β-naphthol molecules form a hydrogen bonded pair, and 4-methylimidazole binds to the host through OH⋯N and NH⋯O hydrogen bonds.