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P Bellomo

Publications and source records attributed to P Bellomo.

10 recordsLinked to original sources
PubMed1981

Synthesis and antibacterial activity of some ester, amides, and hydrazides of 3-carboxyrifamycin S. Relationship between structure and activity of ansamycins.

Esters, amides, and hydrazides of 3-carboxyrifamycin S were synthesized by oxidizing the cyanohydrin of 3-formylrifamycin SV to 3-(cyanocarbonyl)rifamycin S, followed by treatment with alcohols, amines and hydrazines. The in vitro microbiological activity of the derivatives was quite low, especially toward Gram-negative bacteria. This poor activity was not shown to be due to the inadequate inhibiting action on the bacterial DNA-dependent RNA polymerase but to the poor penetration of the compounds through the bacterial cell wall. The microbiological activity was correlated to the chemical properties of the substituent on C3.

Anti-Bacterial Agents↗
PubMed1977

Synthesis and antibacterial activity of some derivatives of tolypomycinone. Relationship between structure and activity in ansamycins.

3-Aminotolypomycinoes and 3,16-diamino-16,17-dihydrotolypomycinones are formed by the addition of primary and secondary amines to tolypomycinone, obtained by mild hydrolysis of the antibiotic tolypomycin Y.3-Amino-16,17-dihydrotolypomycinones are formed by the addition of primary and secondary amines to 16,17-dihydrotolypomycinone. In vitro microbiological tests showed high antibacterial activity in compounds obtained by the addition of primary amines, which must be unbranched in the alpha position to the nitrogen atom to position 3 of the naphthoquinone ring. The relationship between structure and activity is described, and evidence is presented that hydrogen bonding between the amino NH bonded to C3 and the amide CO of tolypomycinone is very important for biological activity.

Escherichia coli↗