Keiji Hemmi

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The present study was undertaken to evaluate whether a novel series of 2,6-diaza-5-oxobicyclo[5.4.0]undeca-1(7),8,10-triene derivatives exhibited antagonistic activity for vasopressin V1 and V2 receptors. Most of these compounds were synthesized and showed a high affinity potential for V2 receptor and low to moderate affinity potential for V1 receptor. The(More)
FR900452, a natural product isolated from the culture broth ofStreptomyces phaeofaciens No. 7739, was found to inhibit PAF-induced rabbit platelet aggregation with an IC50 of 3.7×10−7M. FR900452, 1-methyl-3-[1-[5-methylthiomethyl-6-oxo-3-(2-oxo-3-cyclopenten-1-ylidene)-2-piperazinyl]ethyl]-2-indoline, has an oxocylopentylidene group incorporated as a(More)
Ergosterol is a major sterol component of fungal plasma membranes. The effects of disrupting the Saccharomyces cerevisiae SYR1/ERG3 gene, which encodes sterol C-5 desaturase, an enzyme of ergosterol biosynthesis pathway, were markedly different for different S. cerevisiae strains and growth temperatures. The null mutation of SYR1 (delta syr1) in strain(More)
The structure of WA8242B, a potent novel inhibitor against phospholipase A2, was fully characterized by spectroscopic methods and chemical degradation. The success of total synthesis of WA8242B confirmed the structure and allowed the pharmacological study of WA8242B. The structures of WA8242A1 and A2 were also described.
Several 3-halo-3-(1-haloalkyl)-1(3H)-isobenzofuranones, 3-(1-haloalkylidene)-1(3H)-isobenzofuranones, and 3-bromomethyl-1H-2-benzopyran-1-ones containing masked halo ketone functional groups were synthesized and tested as inhibitors of several serine proteases including human leukocyte (HL) elastase and cathepsin G. While many of the(More)
A series of 3-(deacetoxymethyl)-1-oxa-1-dethiacephalosporins (1) bearing the 7-(alpha-alkoxyimono)acyl side chain were synthesized and their antibacterial properties were examined in comparison with that of FK-749 (2). (Z)-2-(Ethoxyimino)-2-(2 aminothiazol-4-yl)acetic acid was found to be a prefered side chain in the 1-oxa series, and the derivative 18b(More)