- A Mild Heteroatom (O -, N -, and S -) Methylation Protocol Using Trimethyl Phosphate (TMP)-Ca(OH) 2Combination
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A mild heteroatom methylation protocol using trimethyl phosphate (TMP)-Ca(OH)2combination has been developed, which proceeds in DMF, or water, or under neat conditions, at 80 °C or at room temperature. A series of O-, N-, and S-nucleophiles, including phenols, sulfonamides, N-heterocycles, such as 9H-carbazole, indole derivatives, and 1,8-naphthalimide, and aryl/alkyl thiols, are suitable substrates for this protocol. The high efficiency, operational simplicity, scalability, cost-efficiency, and environmentally friendly nature of this protocol make it an attractive alternative to the conventional base-promoted heteroatom methylation procedures.
- Tang, Yu,Yu, Biao
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- Transition-Metal-Free and Visible-Light-Mediated Desulfonylation and Dehalogenation Reactions: Hantzsch Ester Anion as Electron and Hydrogen Atom Donor
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Novel approaches for N- and O-desulfonylation under room temperature (rt) and transition-metal-free conditions have been developed. The first methodology involves the transformation of a variety of N-sulfonyl heterocycles and phenyl benzenesulfonates to the corresponding desulfonylated products in good to excellent yields using only KOtBu in dimethyl sulfoxide (DMSO) at rt. Alternately, a visible light method has been used for deprotection of N-methyl-N-arylsulfonamides with Hantzsch ester (HE) anion serving as the visible-light-absorbing reagent and electron and hydrogen atom donor to promote the desulfonylation reaction. The HE anion can be easily prepared in situ by reaction of the corresponding HE with KOtBu in DMSO at rt. Both protocols were further explored in terms of synthetic scope as well as mechanistic aspects to rationalize key features of desulfonylation processes. Furthermore, the HE anion induces reductive dehalogenation reaction of aryl halides under visible light irradiation.
- Heredia, Micaela D.,Guerra, Walter D.,Barolo, Silvia M.,Fornasier, Santiago J.,Rossi, Roberto A.,Budén, Mariá E.
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supporting information
p. 13481 - 13494
(2020/12/15)
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- O- and N-substituted derivatives of planetol as valuable bioactive compounds
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The compounds bearing sulfamoyl and acetamoyl groups have been found to show various biological activities. In the present research work, a series of O- and N-substituted derivatives were synthesized, starting with planetol (1). First N-methyl-4-hydroxyanilinium sulfate (1; planetol or metol) was treated with different aryl sulfonyl chlorides (2a-i) using aq. sodium carbonate solution as reaction medium to yield N-substituted derivatives 3a-i. The electrophile, N-(2,3-dihydro-1,4-benzodioxin-6-yl)-2-bromoacetamide (5) was prepared by the reaction of 2,3-dihydro-1,4-benzodioxin-6-amine (4) and 2-bromoacetylbromide in a weak basic aqueous medium. The target O-substituted molecules 6a-i, were synthesized by gearing up the electrophile 5, with the molecules 3a-i, in a polar aprotic solvent using LiH as an activator. The proposed structures of all the synthesized molecules were corroborated by IR,1H NMR and EIMS spectral data. The in vitro enzyme inhibition and antibacterial studies rendered the synthesized molecules as better cholinesterase inhibitors and moderately better antibacterial agents. To explore the binding modes of the synthesized compounds, all of them were computationally docked against the active sites of acetyl cholinesterase (AChE), butyryl cholinesterase (BChE) and lipoxygenase (LOX). The compounds showed significant interactions and good correlation with the experimental data.
- Irshad, Misbah,Abbasi, Muhammad Athar,Aziz-Ur-Rehman,Rasool, Shahid,Siddiqui, Sabahat Zahra,Ahmad, Irshad,Ashraf, Muhammad,Lodhi, Muhammad Arif,Jamal, Syed Babar
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p. 1151 - 1160
(2014/06/09)
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