Reported herein is the first purely chemical method for the dynamic kinetic resolution (DKR) of unprotected racemic α-amino acids (α-AAs), a method which can rival the economic efficiency of the enzymatic reactions. The DKR reaction principle can be readily applied for S/R interconversions of α-AAs, the methodological versatility of which is unmatched by biocatalytic approaches. The presented process features a virtually complete stereochemical outcome, fully recyclable source of chirality, and operationally simple and convenient reaction conditions, thus allowing its ready scalability. A quite unique and novel mode of the thermodynamic control over the stereochemical outcome, including an exciting interplay between axial, helical, and central elements of chirality is proposed.
Alcohol-like liver injury (ALLI) in non-alcoholics has not been elucidated in Japan. The present study attempted to characterize the clinicopathologic features of ALLI in routine liver biopsies. ALLI was found in 1% of 561 biopsy cases obtained from 1988 to May, 1991 at Kanazawa University Hospital. Laboratory data characteristically showed only a mild to moderate degree of dysfunction, and none of the cases exhibited jaundice. Hepatic histology showed a mild to moderate degree of perivenular, pericellular and/or portal stellate fibrosis with a varying degree of fatty change and inflammatory cell infiltration. Portal stellate fibrosis with a varying degree of cell infiltration was more severe than the centrilobular or pericellular fibrosis in all cases. Intralobular inflammatory cell infiltration was associated with spotty or single hepatocyte necrosis, but extensive hepatocyte necrosis was not observed. Neutrophil infiltration was absent or minimal, and lymphocytes predominated in all cases. Mallory bodies were rare and were found in a few hepatocytes of only one of the 7 cases. The above histologic findings in ALLI were very similar to those seen in liver disease in Japanese alcoholics, and were somewhat different from ALLI reported in Western countries. In cases in which hepatic fibrosis, characterized by pericellular, perivenular or portal stellate fibrosis dominated without apparent hepatic necrosis and inflammation, the term "non-alcoholic steatofibrosis" is more suitable to depict its liver histology, being very similar to the alcoholic fibrosis frequently seen in Japanese alcoholics.
Taking shape: the ability of a Lewis acid catalyst to distinguish between aromatic and aliphatic hydrocarbon moieties was accomplished by using cage-shaped borate catalysts B(OC(6)H(3)Aryl)(3)CH having a π pocket derived from aryl substituents surrounding the boron center. The catalyst predominantly activated aromatic aldehydes over aliphatic ones for reaction.
We report a discovery of a new rimantadine [1-(1-adamantyl)ethanamine]-derived chiral ligand and its application for the preparation of α-amino acids using the second-order asymmetric transformation approach. The operational ease of experimental procedures coupled with excellent chemical yields and stereochemical outcome suggests some potential synthetic generality of this approach.
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