Search

The behavior of thioacetoacetanilide (1) and/or α-arylhydrazono-thioacetoacetanilides 4 toward many different α-halocarbonyl compounds was demonstrated. Thus, reactions of 1 with α-bromoketones (bromoacetone and phenacyl bromide) and hydrazonoyl bromides afforded the corresponding thiazole, thiophene and 1,3,4-thiadiazole derivatives, respectively. The synthesis and reactivity of thiazolidin-5-one 2 toward aromatic diazonium chlorides and aromatic aldehydes were described. Most of the synthesized compounds were screened for their antibacterial and antifungal activities and showed accepted antimicrobial activities with respect to the control drugs.

The reaction between phenacyl bromide and 2-mercaptobenzimidazole has been studied in 12 different protic and aprotic solvents. The kinetic study shows that the reaction is second-order with first-order dependence each on (phenacyl bromide) and (2-mercaptobenzimidazole). Analysis of rate data shows that there is no direct correlation between the rate constant and dielectric constant of the solvent. Correlation of rate data with different solvent parameters like hydrogen bond acceptor basicity, polarizability and solvent electrophilicity, using linear multiple regression analysis shows that the reaction is influenced by these properties of the solvent. From the regression coefficients, information on the mode of solvation of the reactants and the transition state is obtained. The reaction has also been studied at different temperatures and the thermodynamic parameters Δ H #, Δ S # and Δ G # are evaluated.

2-Methylpyridine (1a), 2,6-dimethylpyridine (1b), 2-methylpyrazine (1c) and 2-methylquinoline (1d) were treated with lithium diisopropylamide (LDA) in THF at low temperature followed by carbon disulfide to give the dianion (5). Reactions of dianion (5) with iodomethane, 1,2-dibromoethane, ethyl chloroacetate, α -chloroacetonitrile or phenacyl bromide gave 6a–c, 6e, 9, 10, 11, 12 and 13, respectively. Reactions of dianion (5) with 1,2-dibromoethene gave the dithiocarboxylic acids (14a–c) rather than a dithiolene, and reaction of dianion (5a) with aqueous ammonium persulfate gave 15. Treatment of 2-methylpyridine (1a) with lithium diisopropylamide (LDA) and 2-bromopyridine afforded tetra-2-pyridylmethane (18) as the main product.

An expeditious, solvent-free, and high yielding synthesis of nitrogen containing heterocycles from 1,2,4-s-triazole, benzoin, chloroacetic acid or phenacyl bromide under microwave irradiation is described. This improved greener synthetic methodology provides a simple and straightforward one-pot approach for the synthesis of a variety of heterocycles.