Polyethylene Glycol-400 Prompted an Efficient Synthesis of Thienyl Pyrazolo[ 1,5-a] Pyrimidines as Microbial Inhibitors.

AIMS: The aim of this present work was to design and establish an efficient synthesis of new thienyl pyrazolo[1,5-a] pyrimidines using an environmentally friendly reaction solvent. Further, the newly synthesized compounds were evaluated for antimicrobial activity. MATERIALS AND METHODS: A series of thienyl pyrazolo[1,5-a] pyrimidines have been synthesized by the condensation reaction of 4-(4'-chloro-phenylazo)-5-amino pyrazole with α, ß- unsaturated carbonyl composites (chalcones) using NaOH in polyethylene glycol- 400 as a green reaction solvent. The dissemination technique recommended by the National Clinical Laboratory Standards Committee was used to study the antimicrobial activities of synthesized compounds. RESULTS AND DISCUSSION: Polyethylene glycol-400 prompting an efficient synthesis of thienyl pyrazolo[1,5-a] pyrimidines have been discussed. Excellent yields of the products were obtained in a shorter reaction time using PEG 400 as a green reaction solvent. The reaction solvent was recovered and reused without the loss of its activity. The synthesized compounds have shown interesting antibacterial activity. Hydroxyl and halo substitution with thienyl moiety emerged as an active antibacterial and antifungal study. CONCLUSION: The advantage of this methodology is that it incorporates the green method, has excellent yields, easy workup, avoids toxic solvents, and an expensive catalyst. The new dimension pyrazolo[1,5-a] pyrimidine derivatives with thienyl moiety exhibit promising anti-microbial activity.

Synthesis and antimicrobial activity of novel pyrazolo[3,4-d]pyrimidin derivatives.

Pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one derivatives have been prepared by cyclocondensation of ethyl 2-cyano-3,3-bis(methylthio)prop-2-enoate with 2-amino-4-(substitutedphenyl)thiazole to give 3-cyano-2-methylthio-4-oxo-4H-6-(substitutedphenyl)thiazolo[3,2-a]pyrimidin (2a-j) and further reacting with hydrazine hydrate to yield the target compounds (3a-j). The chemical structure of the compounds was confirmed by IR and (1)H NMR spectral data. All the compounds of the series have been screened for their antibacterial and antifungal activity studies. The result revealed that all compounds showed significant antimicrobial activity.

Poly(ethylene glycol) (PEG-400) as an alternative reaction solvent for the synthesis of some new 1-(4-(4'-chlorophenyl)-2-thiazolyl)-3-aryl-5-(2-butyl-4-chloro-1H-imidazol-5yl)-2-pyrazolines and their in vitro antimicrobial evaluation.

Several 1-(4-(4'-chlorophenyl)-2-thiazolyl)-3-aryl-5-(2-butyl-4-chloro-1H-imidazol-5yl)-2-pyrazoline derivatives were prepared by the base catalyzed treatment of appropriate chalcones with 4-(4'-chlorophenyl)-2-hydrazino-thiazole in poly (ethylene glycol) (PEG-400) as an alternative reaction solvent. All the synthesized compounds were tested for their antimicrobial activities against Escherichia coli (MTCC 2939), Salmonella typhi (MTCC 98), Staphylococcus aureus (MTCC 96), Bacillus subtilis (MTCC 441), Aspergillus niger (MTCC 281), Trichoderma viridae (MTCC 167), Penicillium chrysogenum (MTCC 160), Fusarium moniliforme (MTCC 156) and Candida albicans (MTCC 183). Most of the compounds showed potent antibacterial and antifungal activity.

Synthesis and biological activity of pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one derivatives: in silico approach.

Xanthine oxidase (XO) is responsible for the pathological condition called gout. Inhibition of XO activity by various pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidine-4-one derivatives was assessed and compared with the standard inhibitor allopurinol. Out of 10 synthesized compounds, two compounds, viz. 3-amino-6-(2-hydroxyphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3b) and 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3g) were found to have promising XO inhibitory activity of the same order as allopurinol. Both compounds and allopurinol inhibited competitively with comparable Ki (3b: 3.56 microg, 3g: 2.337 microg, allopurinol: 1.816 microg) and IC(50) (3b: 4.228 microg, 3g: 3.1 microg, allopurinol: 2.9 microg) values. The enzyme-ligand interaction was studied by molecular docking using Autodock in BioMed Cache V. 6.1 software. The results revealed a significant dock score for 3b (-84.976 kcal/mol) and 3g (-90.921 kcal/mol) compared with allopurinol (-55.01 kcal/mol). The physiochemical properties and toxicity of the compounds were determined in silico using online computational tools. Overall, in vitro and in silico study revealed 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3g) as a potential lead compound for the design and development of XO inhibitors.

An improved procedure for synthesis of some new 1,3-diaryl-2-propen-1-ones using PEG-400 as a recyclable solvent and their antimicrobial evaluation.

A simple and convenient route is described for the synthesis of novel hetero 1,3-diaryl-2-propen-1-ones (chalcones) by using recyclable PEG-400 as an alternative reaction solvent. The reaction is clean with excellent yield, shorter reaction time and reduces the use of volatile organic compounds (VOCs). All the synthesized compounds were evaluated for their antimicrobial activities against several pathogenic representatives.