Microwave Induced Green Synthesis: Sustainable Technology for Efficient Development of Bioactive Pyrimidine Scaffolds.

Microwave radiation is used as a heating source during the synthesis of heterocyclic compounds. The heating mechanisms involved in microwave-induced synthesis include dipolar polarization and ionic conduction. This heating technology follows the green protocol as it involves the use of recyclable organic solvents during synthesis. The microwave heating approach offers a faster rate of reaction, easier work-up procedure, and higher product yield with purity and also reduces environmental pollution. So, microwave heating is applied as a sustainable technology for the efficient production of pyrimidine compounds as one of the heterocyclic moieties. Pyrimidine is a six-membered nitrogenous heterocyclic compound that plays a significant role due to several therapeutic applications. This moiety acts as an essential building block for generating drug candidates with diverse biological activities, including anti-cancer (capecitabine), anti-thyroid (propylthiouracil), antihistaminic (pemirolast), antimalarial (pyrimethamine), antidiabetic (alloxan), antihypertensive (minoxidil), anti-inflammatory (octotiamine), antifungal (cyprodinil), antibacterial (sulfamethazine), etc. This review is focused on the synthesis of pyrimidine analogs under microwave irradiation technique and the study of their therapeutic potentials.

Green Synthetic Approach: An Efficient Eco-Friendly Tool for Synthesis of Biologically Active Oxadiazole Derivatives.

Green synthetic protocol refers to the development of processes for the sustainable production of chemicals and materials. For the synthesis of various biologically active compounds, energy-efficient and environmentally benign processes are applied, such as microwave irradiation technology, ultrasound-mediated synthesis, photo-catalysis (ultraviolet, visible and infrared irradiation), molecular sieving, grinding and milling techniques, etc. Thesemethods are considered sustainable technology and become valuable green protocol to synthesize new drug molecules as theyprovidenumerous benefits over conventional synthetic methods.Based on this concept, oxadiazole derivatives are synthesized under microwave irradiation technique to reduce the formation of byproduct so that the product yield can be increased quantitatively in less reaction time. Hence, the synthesis of drug molecules under microwave irradiation follows a green chemistry approach that employs a set of principles to minimize or remove the utilization and production of hazardous toxic materials during the design, manufacture and application of chemical substances.This approach plays a major role in controlling environmental pollution by utilizing safer solvents, catalysts, suitable reaction conditions and thereby increases the atom economy and energy efficiency. Oxadiazole is a five-membered heterocyclic compound that possesses one oxygen and two nitrogen atoms in the ring system.Oxadiazole moiety is drawing considerable interest for the development of new drug candidates with potential therapeutic activities including antibacterial, antifungal, antiviral, anticonvulsant, anticancer, antimalarial, antitubercular, anti-asthmatic, antidepressant, antidiabetic, antioxidant, antiparkinsonian, analgesic and antiinflammatory, etc. This review focuses on different synthetic approaches of oxadiazole derivatives under microwave heating method and study of their various biological activities.

Stability-indicating RP-HPLC method for simultaneous estimation of levosalbutamol sulfate and theophylline in combined dosage form

A novel, simple, accurate and precise RP-HPLC method for simultaneous determination of levosalbutamol sulfate and theophylline has been developed and validated. Separation was achieved on a Phenomenex; C18 column (250 mm × 4.6 mm i.d., 5 µm) using methanol: 10 mM TBAHS(tetrabutyl ammonium hydrogen sulfate) (50:50, v/v) as mobile phase at flow rate of 1.0 mL.min-1. The UV detection wavelength was 274 nm. The linearity is obeyed over a concentration range of 0.5-150 µg.mL-1 with correlation coefficient of 0.999 for both the drugs. The proposed method was validated by determining accuracy, precision, stability and system suitability parameters. The method was found to be robust. Specificity of the method was determined by subjecting the drugs to various stress conditions like acid, alkali, oxidation, thermal and photolytic degradation. The method was used successfully for the simultaneous determination of levosalbutamol sulfate and theophylline in syrup dosage form.

Desenvolveu-se e validou-se método de RP-HPLC novo, simples, exato e preciso de determinação simultânea do sulfato de levossalbutamol e teofilina.. A separação foi efetuada em uma coluna Phenomenex; C18 (250 mm x 4,6 mm d.i., 5 µm) utilizando metanol: TBAHS (hidrogenossulfato de tetrabutilamônio) 10 mM (50:50, v/v) como fase móvel, com fluxo de 1,0 mL.min-1. O comprimento de onda de detecção no UV foi 274 nm. Observou-se linearidade na faixa de concentração de 0,5-150 µg mL-1, com coeficiente de correlação de 0,999 para ambos os fármacos. O método proposto foi validado determinando-se exatidão, precisão, estabilidade e parâmetros de adequação do sistema. O método mostrou-se robusto. A especificidade do método foi determinada submetendo os fármacos a várias condições de estresse, como ácido, álcali, oxidação, degradação térmica e fotolítica. O método foi usado com sucesso para a determinação simultânea do sulfato de levossalbutamol e teofilina na forma de xarope.