S-Aryl(tetramethyl)isothiouronium salts as possible antimicrobial agents--III.

A series of S-Aryl(tetramethyl)isothiouronium salts were prepared and evaluated in vitro for antimicrobial activity. Some compounds revealed interesting inhibiting action on Gram-positive bacteria which is noteworthy in view of the large number of strains antagonized and of the low MIC values. The possible influence of decomposition kinetics to the corresponding mercaptoderivatives was intestigated and compared with those of salts previously studied.

Synthesis and antimicrobial activity of monoalkylcarbamic and thiocarbamic esters of 3-mercapto-1,2,4-benzothiadiazine-1,1-dioxide and of its Bz-derivatives.

A new series of monoalkylcarbamic esters of 3-mercapto-1,2,4-benzothiadiazine-1,1-dioxide (I) and of its 6-chloro- and 5,7-dichloroderivatives [compounds (II leads to XVI)] and a series of monoalkylthiocarbamic esters of (I) [compounds (XVII leads to XIX)] were synthesized and evaluated in vitro for antimicrobial activity. All the substances studied have been found to possess an inhibiting action on one or more strains of mycetes of the genus Candida and on some strains of Gram-positive bacteria belonging to the genus Staphylococcus. Moreover, some compounds have shown a bacteriostatic effect on a strain belonging to the genus Streptococcus. None of the substances tested was active on Gram-negative schizomycetes.

[Antimicrobial activity of derivatives of 1,2,4-benzothiadiazine-1,1-dioxide. VIII]. / Azione antimicrobica di derivati dell'1,2,4-benzotiadiazin-1,1-diossido. Nota VIII.

The antimicrobial activity of a series of fluoro derivatives of benzothiadiazine and sulfonamides was studied. The compounds tested can be grouped as: a) 3-alkylmercapto derivatives of 6-trifluoromethyl-1,2,4-benzothiadiazine-1,1-dioxide (III leads to VI); the 3-mercapto precursor (VII) and the related 3-picolinic salt (VIII); b) 3-trifluoromethyl derivatives of 1,2,4-benzothiadiazine-1,1-dioxide and of its benzene substituted derivatives (IX leads to XVI); c) trifluoroacetylaminobenzenesulfonamides (XVII leads to XXV). Two of the 3-alkylmercapto compounds [(V) and (VI)] showed marked inhibitory activity against some strains of Staphylococcus, Streptococcus and Diplococcus. None of the compounds tested proved active against Gram-negative schizomycetes (genera Salmonella, Shigella, Escherichia, Proteus, Pseudomonas, Enterobacter, Klebsiella, Serratia, Yersinia, Providencia) or against yeasts (Candida).

[Antimicrobial effect of derivatives of 1,2,4-benzothiadiazin-1,1-dioxide. VII]. / Azione antimicrobica di derivati dell'1,2,4-benzotiadiazin-1,1-diossido. Nota VII.

Series of alkyl derivatives of the following have been prepared: 5,7-dichloro- [compounds (II leads to V)], 6-methyl- [compounds (VI leads to IX)] and 6-methoxy-3-mercapto-1,2,4-benzothiadiazine-1,1-dioxide [compounds (X leads to XIII)]. The products were tested for antimicrobial activity. Studies were also made of the corresponding 3-mercapto precursors (XIV, XV, XVI) and the relative 3-picolinium salts (XVII, XVIII, XIX) and also of the 3-picolinium salts of 6-chloro-, 7-chloro- and 6,7-dichloro-3-mercapto-1,2,4-benzothiadiazine-1,1-dioxide (XX, XXI, XXII). Some of the 3-alkylmercapto compounds, and especially the 5,7-dichloro derivative, inhibited various strains of Gram-positive bacteria of the genus Staphylococcus, while the same substances proved much less effective against the genera Streptococcus and Diplococcus. Antimicrobial activity appeared to be influenced by the length of the alkyl chain as well as by the nature and position of the substituents on the benzene ring. The compounds proved inactive against the Gram-negative schizomycetes (Salmonella, Shigella, Escherichia, Proteus, Pseudomonas. Enterobacter, Klebsiella, Serratia, Yersinia, Providencia) and against yeasts (Candida) with the exception of compound (V) which showed slight bacteriostatic action against three strains of Candida albicans.