A new and efficient protocol was developed for synthesis of benzothiazoles as a potential antimicrobial and antioxidant agent using γ-Valerolactone (GVL) as catalyst and solvent under environmentally friendly conditions. The developed synthetic protocol represents a very simple and a novel route for the synthesis of 2substituted benzothiazole derivatives. In addition, an ultrasound irradiation technique was successfully implemented for performing the reactions in shorter reaction times. The synthesized benzothiazoles were evaluated for antimicrobial and antioxidant activity and was analysed for ADME properties.

A general, highly efficient, and green protocol for the synthesis of biologically important spiro[indoline-3,4 0 -pyrano[3,2-c]chromene derivatives is developed by one-pot, three-component approach involving substituted isatin, active methylene group, and 4-hydroxy coumarin. This report describes the use of γvalerolactone as a green reaction media for a variety of substrates. The advantageous features of this methodology are the environmentally benign character, operational simplicity, high yield processing (91-96%), easy handling, and the reaction medium can be recycled and reused several times without significant loss of its efficiency. White solid;Scheme 3. Plausible mechanism of spiro[indoline-3,4 0 -pyrano[3,2-c]chromene derivatives 4a-q. [Color figure can be viewed at wileyonlinelibrary.com] 2820 F. Diwan and M. Farooqui

A new facile, green and efficient protocol was developed for synthesis of Dihydropyrano [2,3-c] pyrazoles using gluconic acid aqueous solution (GAAS), as catalyst and solvent under environmentally friendly conditions. The advantageous features of this methodology are the environmentally benign character, operational simplicity, high yield processing (91-96%), easy handling; reaction medium can be recycled and reused several times without significant loss of its efficiency. The synthesized compounds were evaluated for antimicrobial and antioxidant activity and also analyzed for ADME properties. The structure of compounds has been confirmed by IR, 1H NMR, 13C NMR, Mass spectrometry and elemental analysis.

A facile one-pot, three-component protocol, for the large scale process of cyanide insertion was developed for synthesis of Cyanolactone (3) [Chemical name (11S, 21R)-11,12-dideoxy-6-O-methyl-2’,4’’-O-bis-(triethylsilyl)-12,11-[oxycarbonyl-(cyano)-methylene]-erythromycin A] as a key drug intermediate of Nafithromycin (6). The cesium carbonate used as a base for cyclisation and carried out insitu 1,4 Michael addition. Furthermore methanol as reaction promotor, which reacts with Trimethylsilyl cyanide (TMSCN) to produce methoxytrimethylsilane and liberate cyanide as nucleophile, which undergoes insitu nucleophilic substitution on 7 by SN2 pathway resulting in the asymmetric compound 3. This procedure has major advantages like insitu cyanide generation under close condition, cost-effective, short reaction time, good atom economy, ease of operation at manufacturing scale. The most significant aspect of the process was that it did not involve any direct handling of poisonous cyanide compounds like potassium or sodium cyanide. In addition, a key feature of optimization and isolation on kilogram scale is described herein.