Ram Lakhan

Synthesis and antimicrobial activity of 1-aryl-2-amino-3-(4-arylthiazol-2-yl)/(benzothiazol-2-yl)guanidines.

The synthesis of fifteen new 1-aryl-2-amino-3-(4-arylthiazol-2-yl)/(benzothiazol-2-yl)gua nidines is described. They were screened for their antimicrobial susceptibility by the standard disc diffusion method of the World Health Organization (WHO) and the activities compared with that of standard strain of Escherichia coli NCTC 10418. The sensitive aminoguanidines were further subjected to the minimum inhibitory concentration (MIC) test.

A convenient preparation of 2-thioxo-4(3H)-quinazolinones

A simple method is described for the preparation of 3-aryl-2-thioxo-4(3H)-quinazolinones (4) by the reaction of anthranilic acids and ammonium or triethylammonium N-aryl-dithiocarbamates in ethanol. The method is also applicable to the preparation of 3-ethyl-2-thioxo-4(3H)-quinazolinone.

Chemoselective Reaction of Benzoylisothiocyanates with Hydroxyl Group of Salicylamide: a New and Convenient Entry Into 2-Aryl-4H-benzo[e][1,3]oxazin-4-ones

Abstract The reactions of benzoylisothiocyanates with salicylamide in pyridine-xylene solution occurs chemoselectively at the hydroxyl group of the salicylamide to afford the corresponding O-benzoyl derivatives. The latter products, on prolonged heating in pyridine-xylene solution, undergo cyclodehydration to give 2-aryl-4H-benzo[e][1,3]oxazin-4-ones in good yields. These compounds could also be synthesized by a direct one-pot reaction of benzoylisothiocyanates with salicylamide by slow addition of benzoylisothiocyanates into a solution of salicylamide in xylene-pyridine solution under reflux. The products have been characterized on the basis of satisfactory analytical and spectral data. GRAPHICAL ABSTRACT

The synthesis and evaluation of 2-imino-3-(4-arylthiazol-2-yl)-4-thiazolidinones and their 5-arylidene derivatives as potential agricultural fungicides

A series of new 2-imino-3-(4-arylthiazol-2-yl)-4-thiazolidinones and their 5-arylidene derivatives have been synthesized from 2-amino-4-arylthiazoles as starting materials. The reaction mechanism has also been critically examined. Of all the synthetic compounds tested against the agricultural fungiTrichoderma harzianum andCurvularia lunata, two compounds, namely 2-imino-3-(4-p-chlorophenylthiazol-2-yl)-4-thiazolidinone and S-benzylidine-2-imino-3-(4-p-tolylthiazol-2-yl)-4-thiazolidinone exhibited the most potent fungicidal effect.