Synthesis of Deuterated 1,2,3-Triazoles

The copper-catalyzed azide–alkyne cycloaddition (CuAAC) is a highly effective method for the selective incorporation of deuterium atom into the C-5 position of the 1,2,3-triazole structure. Reactions of alkynes and azides can be conveniently carried out in a biphasic medium of CH₂Cl₂/D₂O, using the CuSO₄/Na ascorbate system. The mildness of the method renders it applicable to substrates of relatively high complexity, such as nucleosides. Good yields and high levels of deuterium incorporation were observed. A reaction conducted in equimolar H₂O and D₂O showed 2.7 times greater incorporation of hydrogen atom as compared to deuterium. This is consistent with the H⁺ and D⁺ ion concentrations in H₂O and D₂O, respectively. With appropriately deuterated precursors, partially to fully deuterated triazoles were assembled where the final deuterium atom was incorporated in the triazole-forming step

Immobilized lipase from Lactobacillus plantarum in meat degradation and synthesis of flavor esters

Microbial lipases owing to their broad substrate specificity are widely used in various industrial applications like food processing, organic synthesis, detergent formulation and oil manufacturing. In the current study the immobilized lipase from Lactobacillus plantarum was found novel in degrading meat which can be applied in medical field and also in synthesizing different short chain fatty acid esters like 2,3,4-hydroxybenzyl acetates and triazole ester which makes a great impingement in natural flavor industry. The 4-hydroxybenzyl acetate obtained can also be used in cosmetics

Evaluating hydrological alterations and recommending minimum flow release from the Ujjani dam to improve the Bhima River ecosystem health

Numerous anthropogenic activities like the construction of large dams, storages, and barrages changed the watershed characteristics impacting ecosystem health. In this study, the hydrological alterations (HAs) that have occurred in the Bhima River due to the construction of the Ujjani dam were analyzed. The hydraulic analysis is also performed to determine the hydraulic parameter and recommend the lowest flow release from the dam for improving ecosystem health. Fifty-eight years of data starting from the year 1960 to 2018 were gathered at Yadgir station, which is located downstream of the Ujjani dam. The data were divided into pre- and post-construction river flow discharge. To check for the change in the river flow regime for the post-dam construction period, HA was calculated using Flow Health Software (FHS). The results demonstrate that the dam impoundment reduces high flows primarily by storing flood flow for water supply, irrigation, etc. The velocity and depth provided by the environmental design flow for a flow health (FH) score of 0.62 give a very good habitat to fishes. A minimum release of 24.8 m3/s from the dam is recommended. This study will help policymakers mitigate the impacts of degrading ecosystem health of the Bhima River. HIGHLIGHTS The study analyzes hydrological alterations caused by the construction dam, which have disturbed the river flow regime.; A hydraulic study was performed to determine the hydraulic parameter and to recommend the lowest flow release from the dam for habitat context.; Pre- and post-construction river flow discharge data were used to analyse the impact of human activities on ecology of river.

Facile functionalization at the C4 position of pyrimidine nucleosides via amide group activation with (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP) and biological evaluations of the products (vol 15, pg 1130, 2017)

Correction for 'Facile functionalization at the C4 position of pyrimidine nucleosides via amide group activation with (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP) and biological evaluations of the products' by Hari K. Akula, et al., Org. Biomol. Chem., 2017, DOI: 10.1039/c6ob02334g.crosscheck: This document is CrossCheck deposited related_article: http://dx.doi.org/10.1039/C6OB02334G copyright_licence: The Royal Society of Chemistry has an exclusive publication licence for this journal copyright_licence: This article is freely available. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (CC BY 3.0) history: Received 11 January 2017; Accepted 11 January 2017; Advance Article published 19 January 2017; Version of Record published 1 February 2017status: publishe

Facile functionalization at the C4 position of pyrimidine nucleosides via amide group activation with (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP) and biological evaluations of the products

Reactions of O-t-butyldimethylsilyl-protected thymidine, 2'-deoxyuridine, and 3'-azidothymidine (AZT) with (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP) leads to activation of the C4 amide carbonyl by formation of putative O(4)-(benzotriazol-1-yl) derivatives. Subsequent substitution with alkyl and aryl amines, thiols, and alcohols leads to facile functionalization at this position. Reactions with amines and thiols were conducted either as a two-step, one-pot transformation, or as a one-step conversion. Reactions with alcohols were conducted as two-step, one-pot transformations. In the course of these investigations, the formation of 1-(4-pyrimidinyl)-1H-benzotriazole-3-oxide derivatives from the pyrimidine nucleosides was identified. However, these too underwent conversion to the desired products. Products obtained from AZT were converted to the 3'-amino derivatives by catalytic reduction. All products were assayed for their abilities to inhibit cancer cell proliferation and for antiviral activities. Many were seen to be active against HIV-1 and HIV-2, and one was active against herpes simplex virus-1 (HSV-1).crosscheck: This document is CrossCheck deposited related_article: http://dx.doi.org/10.1039/C7OB90013A related_data: Supplementary Information identifier: Mahesh K. Lakshman (ORCID) copyright_licence: The Royal Society of Chemistry has an exclusive publication licence for this journal history: Received 26 October 2016; Accepted 16 December 2016; Advance Article published 5 January 2017; Version of Record published 1 February 2017status: publishe

Ruthenium-Catalyzed C–H Bond Activation Approach to Azolyl Aminals and Hemiaminal Ethers, Mechanistic Evaluations, and Isomer Interconversion

C­(sp³)–N bond-forming reactions between benzotriazole and 5,6-dimethylbenzotriazole with <i>N</i>-methylpyrrolidinone, tetrahydrofuran, tetrahydropyran, diethyl ether, 1,4-dioxane, and isochroman have been conducted using RuCl₃·3H₂O/<i>t</i>-BuOOH in 1,2-dichloroethane. In all cases, <i>N</i>1 and <i>N</i>2 alkylation products were obtained, and these are readily separated by chromatography. One of these products, 1-(isochroman-1-yl)-5,6-dimethyl-1<i>H</i>-benzotriazole, was examined by X-ray crystallography. It is the first such compound to be analyzed by this method, and notably, the benzotriazolyl moiety is quasi-axially disposed, consistent with the anomeric effect. This has plausible consequences, not observed previously. In contrast to other hemiaminal ether-forming reactions, which proceed via radicals, this Ru-catalyzed process is not suppressed in the presence of a radical inhibitor. Therefore, an oxoruthenium-species-mediated rapid formation of an oxocarbenium intermediate is believed to occur. In the radical-trapping experiment, previously unknown products containing both the benzotriazole and the TEMPO unit have been identified. In these products, it is likely that the benzotriazole is introduced via a Ru-catalyzed C–N bond formation, whereas C–O bond-formation with TEMPO occurs via a radical reaction. We show that reactions of THF with TEMPO are influenced by ambient light. A competitive reaction of THF and THF-<i>d</i>₈ with benzotriazole indicated that C–H bond cleavage occurs ca. 5 times faster than C–D cleavage. This is comparable to other metal-mediated radical reactions of THF but lower than that observed for a reaction catalyzed by <i>n</i>-Bu₄N⁺I^–. Detailed mechanistic experiments and comparisons are described. The catalytic system was also evaluated for reactions of benzimidazole, imidazole, 1,2,4-triazole, and 1,2,3-triazole with THF, and successful reactions were achieved in each case. In the course of our studies, we discovered an unexpected but significant isomerization of some of the benzotriazolyl hemiaminal ethers. This is plausibly attributable to the pseudoaxial orientation of the heterocycle in the products and the stability of oxocarbenium ions, both of which can contribute to C–N bond cleavage and reformation. Predominantly, the <i>N</i>2-isomers rearrange to the <i>N</i>1-isomers <i>even upon storage at low temperature!</i> This previously unknown phenomenon has also been studied and described