A DFT study on substituents, solvent, and temperature effect and mechanism of Diels-Alder reaction of hexafluoro-2-butyne with furan.

CONTEXT: Furan and its derivatives constitute a vital class of heterocyclic chemistry used widely in organic synthesis via Diels-Alder reactions. As fluorine incorporation has been of great interest due to the limited possible pathways, the present study on [4 + 2] cycloaddition Diels-Alder reaction, between hexafluoro-2-butyne and 2-substituted (NH2, OCH3, OTMS, NHBoc) furans, uses the reaction as a likely route. The computational study revealed that that the reaction is feasible in all conditions and is most favorable for NH2 substituent in furan. The study of the effect of temperature has depicted that low temperature favors the formation of adducts, while the rise in temperature prefers ring opening to form 4-substituted-2,3-di(trifluoromethyl)phenol derivatives. The feasibility of a reaction has been determined by Gibbs energy change. The transition state study has been performed to find the activation energy, C-C single bond formation and global electron density transfer (GEDT) involved in the adduct formation. MEP plots have been used to understand the region of electrophilicity and nucleophilicity character. Furthermore, the mechanism for the formation of phenol products has been discussed. The decomposition of the NHBoc group at higher temperatures has been proved via a proposed mechanism and compared with experimental results. METHODS: The reaction was theoretically investigated using B3LYP hybrid functional with 6-311 + G(d,p) basis sets, in gas phase and under different solvent conditions like water, acetonitrile, and THF. The transition state structures of the adduct were optimized at the lower basis set B3LYP/6-31 + G(d,p) as well as at the higher basis set B3LYP/6-311 + G(d,p) level. The changes in Gibbs energy (∆G) for the formation of products at different temperatures and in various solvents have been calculated at B3LYP/6-311 + G(d,p) level.

Hydrotrope assisted green synthesis of dicoumarols and in silico and in vitro antibacterial, antioxidant and xanthine oxidase inhibition studies.

Aqueous hydrotrope has been employed for the first time to synthesize heteroaryl dicoumarols by condensation of 4-hydroxycoumarin and different heterocyclic aldehydes. This method is highly efficient and green, and the same aqueous hydrotropic solution can be used up to five times without any considerable loss of yield in the product. The synthesized compounds showed good antibacterial potential against Gram-positive (Staphylococcus aureus/NTCC 0997 and B. oceanisediminis) and Gram-negative (Escherichia coli/D0157:H7 and E. coli rosetta) bacterial strains using the Resazurin microtiter plate visual method. The MIC value of 312 µg/ml for compounds 3b, 3k and 3l for S. aureus while 39 µg/ml for compounds 3a, 3b and 3k for E. coli and 625 µg/ml for 3a and 3b for B. oceanisediminis was observed. The compounds were screened via computational methods like molecular docking studies and molecular dynamic simulations with PDB Id's 2W9S and 2EX6. Antioxidant activity was assessed using DPPH and H2O2 assays. Five compounds with the best binding score in molecular docking with XO (PDB ID: 1FIQ) have been tested in an in-vitro study using an enzyme inhibition assay. Novel compound 3b gave the IC50 value of 0.28 µg/ml, comparable to the standard drug Allopurinol.Communicated by Ramaswamy H. Sarma.

Knowledge, Attitudes and Practices Towards COVID-19: A Cross-Sectional Survey.

Aim: To assess the knowledge, attitudes and practices (KAP) regarding the corona virus disease 2019 (COVID-19) pandemic among patients and their attendants visiting the gynaecologic oncology outpatient department (OPD) and to assess the factors associated with a KAP score. Methodology: A KAP cross-sectional survey was conducted over three months exploring KAP relevant to COVID-19. Mann-Whitney U test and Kruskal-Wallis test were used to compare the differences in knowledge, attitude and practice by demographic characteristics. Correlation between knowledge, attitude and practice was done using Spearman's rank correlation test. Binary logistic regression analyses were applied to identify possible determinants of good knowledge, attitude and practice. Results: A total of 521 completed questionnaires were included. The study revealed an overall good knowledge (16.09/20), attitude (8.34/10) and practice (12.73/14) scores. Education status, standard of living (rural/urban) and economic status determined an adequate overall knowledge, attitude and practice score, while an adequate practice score varied significantly by standard of living and education status. Significant positive linear correlations were found between knowledge-attitude (r = 0.513), knowledge-practice (r = 0.407) and attitude-practice (r = 0.407). Conclusion: The study demonstrated good overall knowledge, attitude and practices towards COVID-19 pandemic among gynaecological oncology OPD patients and their attendants. Supplementary Information: The online version contains supplementary material available at 10.1007/s40944-022-00624-1.

Orbital involvement in nonendemic Burkitts lymphoma.

Burkitt's lymphoma (BL) is a rare monoclonal proliferation of Blymphocytes and is classified as a poorly differentiated lymphocytic lymphoma. Typically, Burkitt's lymphoma involves the jaw bones, but the orbit can also be involved. Burkitt"s lymphoma is seen, sporadically in India, and 3 cases of orbital Burkitt's lymphoma were diagnosed during the past 4 years. Three cases of acute proptosis in children are presented to us. The provisional clinical diagnosis was rhabdomyosarcoma and the histopathology revealed Burkitt's lymphoma. The fast growth rate, hematologic manifestations and the urgency of diagnosis are emphasized. We present 3 cases here and review prevailing concepts about Burkitt's lymphoma.