Publications by authors named "Shinya Hisakawa"

The synthesis of a 6-CF-substituted 2-amino-dihydro-1,3-thiazine via N, N-diethylaminosulfur trifluoride (DAST)-mediated cyclization of N-hydroxypropyl thiourea 6 is described. This reaction gave 6-CF-1,3-thiazine 7 with high chemical yield and chemoselectivity, suppressing the common byproduct of oxazine 8. This new protocol enabled access to 6-CF-substituted 1,3-thiazine β-secretase inhibitor 2.

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The structure-activity relationship (SAR) for a novel series of catechol conjugated siderophore cephalosporins is described with their in vitro activities against multi-drug resistant Gram-negative pathogens including Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia and Enterobacteriaceae. Cefiderocol (3) was one of the best molecules which displayed well-balanced and potent activities against multi-drug resistant Gram-negative pathogens including carbapenem resistant bacteria among the prepared compounds with the modified C-7 side chain and the modified C-3 side chain. Cefiderocol (3) is a highly promising parenteral cephalosporin for the treatment of multi-drug resistant Gram-negative infection.

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Aiming to develop selective anticancer drugs, we designed and synthesized three disulfides bearing a folic acid moiety as candidate folate receptor (FR)-targeted prodrugs of thiolate histone deacetylase inhibitors. Among them, compound 1 displayed growth-inhibitory activity toward folate receptor-positive MCF-7 breast cancer cells. The activity of 1 was significantly reduced by free folic acid, suggesting that cellular uptake of 1 is mediated by FR.

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To identify prodrugs of a thiolate histone deacetylase inhibitor NCH-31 that show potent antiproliferative activity and are stable in human plasma, we synthesized several candidate prodrugs of NCH-31. Among these compounds, S-2-methyl-3-phenylpropanoyl compound 2 showed more potent antiproliferative activity and higher stability in human plasma than S-isobutyryl compound NCH-51.

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To find novel histone deacetylase 6 (HDAC6)-selective inhibitors and clarify the structural requirements for HDAC6-selective inhibition, we prepared thiolate analogues designed based on the structure of an HDAC6-selective substrate and evaluated the histone/alpha-tubulin acetylation selectivity by Western blot analysis. Aliphatic compounds 17b-20b selectively caused alpha-tubulin acetylation over histone H4 acetylation. In enzyme assays using HDAC1, HDAC4, and HDAC6, compounds 17a-19a exhibited HDAC6-selective inhibition over HDAC1 and HDAC4.

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A series of suberoylanilide hydroxamic acid (SAHA)-based non-hydroxamates was designed, synthesized, and evaluated for their histone deacetylase (HDAC) inhibitory activity. Among these, methyl sulfoxide 15 inhibited HDACs in enzyme assays and caused hyperacetylation of histone H4 while not inducing the accumulation of acetylated alpha-tubulin in HCT116 cells.

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