- Crystal structure of 1-(2,4,6-trichlorobenzoyloxy) benzotriazole (TCB-OBt): observation of uncommon intermolecular oxygen-oxygen interaction and synthetic application in amidation
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Herein, we investigated the supramolecular assembly of a modified Yamaguchi reagent TCB-OBt. Interestingly, each molecule is interconnected through novel chalcogen-chalcogen (O?O) interaction, π-π stacking, and aromatic C-H?O interaction. Hirshfeld surface analysis confirmed the existence of uncommon O?O interactions. A well-organized supramolecular layer structure and helical arrangement were observed in the crystal structure. TCB-OBt crystallized in the O-substituted desmotropic form. DFT calculations suggest that the O-substituted form is more stable than theN-substituted form (TCB-(N)-OBt). Morphology analysis indicates the formation of a fantastically well organized, continuous block-shaped system. Furthermore, the designed reagent works as an efficient activating reagent for amide bond formation with good yields under mild reaction conditions. Use of this reagent avoided intractable acid chlorides, and this new mixed-anhydride-based reagent may further be applicable for many other organic transformations.
- Dolai, Gobinda,Giri, Rajat Subhra,Mandal, Bhubaneswar,Roy, Sayanta,Sen, Srijit
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p. 19804 - 19811
(2021/11/12)
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- Novel Molecular Hybrids of N-Benzylpiperidine and 1,3,4-Oxadiazole as Multitargeted Therapeutics to Treat Alzheimer's Disease
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Multitargeted hybrids of N-benzylpiperidine and substituted 5-phenyl-1,3,4-oxadiazoles were designed, synthesized, and evaluated against Alzheimer's disease (AD). Tested compounds exhibited moderate to excellent inhibition against human acetylcholinesterase (hAChE), butyrylcholinesterase (hBChE), and beta-secretase-1 (hBACE-1). The potential leads 6g and 10f exhibited balanced inhibitory profiles against all the targets, with a substantial displacement of propidium iodide from the peripheral anionic site of hAChE. Hybrids 6g and 10f also elicited favorable permeation across the blood-brain barrier and were devoid of neurotoxic liability toward SH-SY5Y neuroblastoma cells. Both leads remarkably disassembled Aβ aggregation in thioflavin T-based self- and AChE-induced experiments. Compounds 6g and 10f ameliorated scopolamine-induced cognitive dysfunctions in the Y-maze test. The ex vivo studies of rat brain homogenates established the reduced AChE levels and antioxidant activity of both compounds. Compound 6g also elicited noteworthy improvement in Aβ-induced cognitive dysfunctions in the Morris water maze test with downregulation in the expression of Aβ and BACE-1 proteins corroborated by Western blot and immunohistochemical analysis. The pharmacokinetic study showed excellent oral absorption characteristics of compound 6g. The in silico molecular docking and dynamics simulation studies of lead compounds affirmed their consensual binding interactions with PAS-AChE and aspartate dyad of BACE-1.
- Sharma, Piyoosh,Tripathi, Avanish,Tripathi, Prabhash Nath,Singh, Saumitra Sen,Singh, Surya Pratap,Shrivastava, Sushant Kumar
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p. 4361 - 4384
(2019/10/16)
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- Microwave irradiation and diisopropylcarbodiimide (DIC)/7-aza-1- hydroxybenzotriazole (HOAt): A potent combination for synthesis of variuos hydrazide from N-protected amino acid and hydrazine
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Here we describe a fast and rapid technique for preparation of amino acid hydrazide as well as peptide hydrazide derivatives using diisopropylcarbodiimide (DIC)/1-hydroxybenzotriazoles (HOXt) (X = A or B) under microwave irradiation employing a multimode reactor (Synthos 3000 Aton Paar, GmbH, 1400 W maximum magnetron). A comparison between conventional and microwave irradiation was described. The microwave methodology is rapid, convenient, proceeds under mild conditions. Diisopropylcarbodiimide (DIC)/7-aza-1-hydroxybenzotriazole (HOAt) always gave much better yield (95 - 98%) and purity than diisopropylcarbodiimide (DIC)/1-hydroxybenzotriazole (HOBt).
- Albatal, Mona,Ghani, Mohamad Abdul,El-Faham, Ayman,Al-Hazimi, Hassan M.,Hammud, Hassan H.
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experimental part
p. 419 - 428
(2010/11/04)
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- Facile and chemoselective reduction of carboxylic acids to alcohols using BOP reagent and sodium borohydride
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Hydroxybenzotriazolyl esters, formed in situ from carboxylic acids and BOP reagent, react with sodium borohydride in THF to give alcohols in high yields. This method is convenient, rapid and chemoselective, with such functional groups as nitro, halide, nitrile, azido and ester being unaffected.
- McGeary, Ross P.
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p. 3319 - 3322
(2007/10/03)
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