High pressure, catalytic reduction of
p-nitrosalicylic aryl and aralkyl esters in methanol, ethanol, or benzene, with Raney nickel as the catalyst, gave the esters of
p-aminosalicylic acid in a good yield. The similar reduction of the sodium, calcium, or barium salt in water or dilute ethanol also gave the PAS salts in a good yield. The esters of PAS obtained were phenyl ester (I), guaiacol ester (II),
m-cresol ester (III), thymol ester (IV),
m-methyl-
p-isopropylphenyl ester (V), and benzyl ester (VI). PAS hydrazide was also obtained. Antibacterial action
in vitro against H
37Rv strain of tubercle bacilli was five times that of PAS-sodium 2 H
2O in (I) and (III), and 3.3 times in (II). With H
37Rv R-SM strain, (I) and (III) were 15 times stronger, and (II), 7.5 times stronger. The action was about the same against H
37Rv R-PAS strain. However, (V), the isomer of (IV), was found to be 250 times that of (IV) aginst H
37Rv strain and 200 times against H
37Rv R-SM strain. The antibacterial action of PAS hydrazide was about 1/15 that of isonicotinic acid hydrazide against H
37Rv strain, and 1/13 aginst H
37Rv R-SM strain.
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