A series of novel dihydropyrimidin-2(1H)-ones derivatives is synthesized by using Rhizopus Oryzae lipase biocatalyst in deep eutectic solvent. The reaction is characterized by high efficiency and selectivity, short reaction time, mild and environmentally friendly reaction conditions. The yields are found to be significantly higher and reuse of both the lipase and deep eutectic solvent is possible up to four consecutive cycles. The products are found to exhibit appreciable in vitro antibacterial activity against Echerichia coli, Pseudomonas neumoniae and in vitro antifungal activity against Aspergillus niger and Candida albicans.
The conventional and microwave assisted multicomponent synthesis of disubstituted 1,2,3-triazoles from terminal alkynes and in situ generated organic azide using copper apatite catalyst in water is reported. The catalytic activity is intimately connected to the basicity of the catalyst. The best activities were observed with the copper hydroxyapatite. The catalyst could be used ten times without further treatment and activation under controlled microwave heating. The protocol was also applicable for various alkynes and halides which affords desired product in good to excellent yield.
The aminolytic depolymerization of PET bottle waste with ethanolamine by conventional heating and microwave irradiation heating method was attempted with heterogeneous, recyclable acid catalysts such as beta zeolite (SiO2/ AlO2= 15 Na- form) and montmorillonite KSF. The pure product bis-(2-hydroxyethyl) terephthalamide (BHETA) of aminolysis was obtained in good yield (85- 88%). The BHETA, thus obtained, was subjected to cyclization reaction by heating with polyphosphoric acid as well as by chlorination (using phosphoryl chloride), bromination (using red phosphorous and liquid bromine) and nitration (conc. HNO3 + conc. H2SO4) followed by conventional and microwave irradiation heating in N,N- dimethyl formamide/ potassium carbonate solution. The product so obtained was 2, 2’-(1,4-phenylene)–bis-(2-oxazoline) (PBO), which has applications in polymer synthesis as a chain extender/ chain coupling agent or a cross linker. The productswere analyzed by FTIR, DSC, Mass and NMR (1H and 13C NMR).
A microwave-assisted method was developed for the synthesis of aldol adducts using RuCl3.nH2O-BINAP as an efficient catalyst. Important advantages of this technology include environmentally benign condition, highly accelerated rate of the reaction with an improvement in the chemoselectivity and quality of the products.
A new analytical approach was proposed to monitor the reaction between epoxidized soybean oil and diethylene glycol in the presence of ZnCl2 as an epoxide ring opening catalyst for microwave assisted synthesis of polyol. Infrared spectra of the products were used as the input data, being processed by multivariate curve resolution – alternating least squares (MCR-ALS) for quantitative monitoring. The data obtained in different MW powers were analyzed by MCR factor analysis coupled with ALS optimization procedure. Standard deviation of residuals for experimental data and the variance explained at the optimum condition (r2) were 0.135 and 97.24% respectively.