Antibiotic YC 73 of Pseudomonas origin. 3. Synthesis of thioformin analogues.
In the earlier paper of this series1}, it was reported that YG 73 (I) of a Pseudomonas origin was a cupric complex of an acidic substance named thioformin (II), which could be synthesized by treating N-methylhydroxylamine with potassium dithioformate. Soon after the structure determination of II, the fact that such a simple thiohydroxamic acid derivative as II possesses significant antimicrobial activity prompted us to synthesize structural analogues of II. The analogues represented in the general formula III were readily prepared by the following methods. R\ yS )N-Cf (III) ho/ \h Method A : Direct thioformylation of N-substituted hydroxylamines with potassium dithioformate.
Lawesson's reagent for direct thionation of hydroxamic acids: Substituent effects on LR reactivity
To explore the generality and scope of direct thionation of hydroxamic acids (HAs), the reaction of various structurally diverse HAs with Lawesson's reagent was investigated. The yield of thiohydroxamic acid (THAs) is poor when HAs possess bulky acyl and/or N-substituents, acidic α-hydrogen atoms, or an N-phenyl ring. THAs yields were correlated with Brown sigma parameter. The relative rates of two subsequent processes k and k were also measured. Correlation was also found for methine proton chemical shifts of N-isopropyl benzothiohydroxamic acids. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:676–684, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20259
Antibiotic YC 73 of pseudomonas origin. 1. Production, isolation and properties.
The structure of thioformin, a new acidic antibiotic substance obtained by removing cupric ion from antibiotic YC 73, was shown to be N-methyl-N-thioformylhydroxylamine by degradative and synthetic studies. Numerous metal complexes of thioformin, including the cupric (antibiotic YC 73 itself) and ferric complexes, were also synthesized and characterized.