Jayashree Nath

An “on-water” exploration of CuO nanoparticle catalysed synthesis of 2-aminobenzothiazoles

An “on-water” one-pot process has been engineered for the preparation of 2-aminobenzothiazole from ortho-halo (–F, –Cl, –Br and –I) substituted unsymmetrical thioureas. For ortho –I and –Br substrates the reactions afford 2-aminobenzothiazoles under metal free condition promoted by base. However, the relatively inert ortho –Cl and –F substrates undergo intramolecular arylthiolation only in the presence of CuO nanoparticles yielding 2-aminobenzothiazoles. This methodology provides easy access to aminobenzothiazoles utilising even the ortho –Cl and –F substrates. The catalyst is recyclable several times without loss of substantial activity. Other remarkable features include the wide range of functional group tolerance, absence of chromatographic purification (for ortho –I and –Br substrates) and providing moderate to excellent yield of the products under mild conditions, thus rendering the methodology as a highly eco-friendly alternative to the existing methods.

Molybdenum(VI)-peroxo complex catalyzed oxidation of alkylbenzenes with hydrogen peroxide

The molybdenum(VI) peroxo complex 1, synthesized from the reaction of MoO 3 with H 2 O 2 and 3,5-dimethylpyrazole (dmpz), selectively oxidizes benzylic C-H bonds of alkylbenzenes to the corresponding alcohols and ketones in moderate to good yields in the presence of H 2 O 2 in acetonitrile under reflux (ca. 80°C).

A one-pot preparation of cyanamide from dithiocarbamate using molecular iodine

An efficient one-pot method for the synthesis of cyanamides from dithiocarbamate salts via a double desulfurization strategy using molecular iodine is disclosed. Dithiocarbamates, by the action of iodine yield isothiocyanates in situ, which on treatment with aqueous NH3 give thioureas. The thioureas so generated undergo further oxidative desulfurization with I2 giving corresponding cyanamides in good yields. Environmental benignity, cost effectiveness and high yields are the important attributes of this one pot procedure.

Boric acid catalyzed bromination of a variety of organic substrates: an eco-friendly and practical protocol

Abstract An environmentally benign, easy to operate, and practical protocol for the regioselective bromination of aromatic compounds using boric acid as a recyclable catalyst, KBr as the source of bromide and hydrogen peroxide as the oxidant is described. Peroxoborate generated in solution, from the reaction of boric acid and H2O2, very effectively catalyses the bromination of organic substrates at room temperature in a selective manner. The catalyst used is inexpensive, eco-friendly, safe to handle, and recyclable. The methodology is chemoselective for dibenzylidineacetone and regioselective for the other substrates. High yields of the products, mild reaction conditions, high selectivity, use of H2O or C2H5OH as solvent, and redundancy of bromine are some of the major advantages of the synthetic protocol.

Improved procedure for the preparation of isothiocyanates via iodine-mediated desulfurization of dithiocarbamic acid salts

Abstract We report here an improved procedure for the synthesis of isothiocyanates from the corresponding dithiocarbamic acid salts via a desulfurization strategy using molecular iodine and sodium bicarbonate in water/ethyl acetate biphasic medium. The reagents used are easily available, non-toxic, and cheap. High environmental acceptability of the reagents, cost effectiveness, and high yields are the important attributes of this methodology.

ENVIRONMENTALLY BENIGN ONE-POT SYNTHESIS OF CYANAMIDES FROM DITHIOCARBAMATES USING I2 AND H2O2

Abstract An environmentally benign reaction is devised for the synthesis of cyanamides from dithiocarbamate salts using iodine and H2O2. GRAPHICAL ABSTRACT

Borax: An Ecofriendly and Efficient Catalyst for One-Pot Synthesis of 3,4-Dihydropyrimidine-2(1H)-ones under Solvent-Free Conditions

Borax in the presence of a very small amount of 5 M sulfuric acid efficiently catalyses the three-component condensation of an aldehyde, β-ketoester, and urea or thiourea to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones or 3,4-dihydropyrimidin-2(1H)-thiones in good to excellent yields under solvent-free conditions at 80 °C. Compared with the classical Biginelli reaction conditions, this new method has the advantage of excellent yield, short reaction time (1–2 h), easy workup, and no use of volatile organic solvent.