Metal-Free Oxidative C(sp3)–N Coupling by HBr and DMSO: A Novel Synthesis of 2,3-Dihydroquinazolin-4(1H)-ones

Synlett ◽  
2018 ◽  
Vol 29 (07) ◽  
pp. 912-917 ◽  
Author(s):  
Parviz Ranjbar ◽  
Narjes Rezaei ◽  
Ehsan Sheikhi
Keyword(s):  
Oxidative Cyclization ◽  
Cyclization Reaction ◽  
Primary Amines ◽  
Isatoic Anhydride ◽  
Reaction Conditions ◽  
Coupling Process ◽  
Benzylic Alcohols ◽  
Metal Free ◽  
Novel Synthesis

A metal-free oxidative C(sp3)–N coupling process has been developed for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones. The reaction between primary amines, isatoic anhydride, and benzylic alcohols in the presence of HBr in DMSO at 80 °C affords 2,3-dihydroquinazolin-4(1H)-ones in excellent yields. Under these reaction conditions, benzylic alcohols react with in situ generated bromodimethylsulfonium bromide to form alkoxysulfonium intermediates. These intermediates undergo an oxidative cyclization reaction with primary amines and isatoic anhydride to produce the title products.

scholarly journals Metal-Free Air Oxidation in a Convenient Cascade Approach for the Access to Isoquinoline-1,3,4(2H)-triones

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2177
Author(s):  
Antonia Di Mola ◽  
Consiglia Tedesco ◽  
Antonio Massa
Keyword(s):  
Heterocyclic Compounds ◽  
Aromatic Ketone ◽  
Primary Amines ◽  
Cascade Process ◽  
Staudinger Reaction ◽  
Caspase Inhibitor ◽  
Air Oxidation ◽  
Metal Free ◽  
Free Air

Herein we describe a very useful application of the readily available trifunctional aromatic ketone methyl-2-(2-bromoacetyl)benzoate in reactions with primary amines. An unexpected in situ air oxidation that follows a cascade process allowed the access to a series of isoquinoline-1,3,4(2H)-triones, a class of heterocyclic compounds of great interest containing an oxygen-rich heterocyclic scaffold. A modification of the original protocol, utilizing a Staudinger reaction in the presence of trimethylphosphine, was necessary for the synthesis of Caspase inhibitor trione with free NH group.

Radical Metal-Free Borylation of Aryl Iodides

Synthesis ◽  
2017 ◽  
Vol 49 (21) ◽  
pp. 4759-4768 ◽  
Author(s):  
Sandra Pinet ◽  
Mathieu Pucheault ◽  
Virginie Liautard ◽  
Mégane Debiais
Keyword(s):  
Steric Hindrance ◽  
Radical Mechanism ◽  
Electronic Effects ◽  
Simple Metal ◽  
Reaction Conditions ◽  
Metal Free ◽  
Aryl Iodides ◽  
Reaction Proceeds ◽  
Electronic Effects Of Substituents

A simple metal-free borylation of aryl iodides mediated by a fluoride sp2–sp3 diboron adduct is described. The reaction conditions are compatible with various functional groups. Electronic effects of substituents do not affect the borylation while steric hindrance does. The reaction proceeds via a radical mechanism in which pyridine serves to stabilize the boryl radicals, generated in situ.

Iodine-Mediated Oxidative Cyclization of 2-(Pyridin-2-yl)acetate Derivatives with Alkynes: Condition-Controlled Selective Synthesis of Multisubstituted Indolizines

Synthesis ◽  
2019 ◽  
Vol 52 (03) ◽  
pp. 459-470 ◽  
Author(s):  
Lisheng He ◽  
Yuzhu Yang ◽  
Xiaolan Liu ◽  
Guangyan Liang ◽  
Chunyan Li ◽  
...  
Keyword(s):  
Oxidative Cyclization ◽  
Cyclization Reaction ◽  
Selective Synthesis ◽  
Reaction Conditions ◽  
Stepwise Synthesis

An iodine-mediated oxidative cyclization reaction between 2-(pyridin-2-yl)acetate derivatives and different alkynes has been developed, which provides regioselective and chemoselective syntheses of multiply substituted indolizines under modified reaction conditions. Plausible mechanisms have been proposed to explain the selective syntheses of indolizines. This protocol can be also applied to the stepwise synthesis of 2,2′-biindolizines.

Transition-metal-free oxidative cyclization reaction of enynals to access pyrane-2-one derivatives

2021 ◽  
Author(s):  
Farzaneh Ansari ◽  
Hormoz Khosravi ◽  
Alireza Abbasi Kejani ◽  
Mahsa Armaghan ◽  
Walter Frank ◽  
...  
Keyword(s):  
Transition Metal ◽  
Oxidative Cyclization ◽  
Cyclization Reaction ◽  
Metal Free

K2S2O8 is introduced as an oxygen source and C–H functionalization agent in a novel selective metal-free oxidative cyclization of enynals to synthesize α-pyrone derivatives with a relatively broad substrate scope via the formation of two C–O bonds.

Transition-Metal-Free Synthesis of Thiosulfonates through Radical Coupling Reaction

Synlett ◽  
2018 ◽  
Vol 29 (15) ◽  
pp. 2076-2080 ◽  
Author(s):  
Wen-Ting Wei ◽  
Zhiyong Guo ◽  
Guodong Zhou ◽  
Xu-Dong Xu ◽  
Gan-Ping Chen
Keyword(s):  
Transition Metal ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Coupling Process ◽  
Metal Free ◽  
Radical Coupling ◽  
Radical Coupling Reaction ◽  
High Yields

An efficient and practical transition-metal-free radical ­coupling reaction of sulfonyl hydrazides mediated by NIS/K2S2O8 has been developed to afford a variety of biological activity thiosulfonates in moderate to excellent yields. Compared to a known approach for the synthesis of thiosulfonates from sulfonyl hydrazides, this strategy features high yields, mild reaction conditions, and broad substrate scope. The mechanistic studies revealed that the procedure undergoes via a radical cross-coupling process for the construction of S–S bonds.

Hypervalent Iodine Mediated Efficient Solvent-Free Regioselective Halogenation and Thiocyanation of Fused N-Heterocycles

Synlett ◽  
2019 ◽  
Vol 30 (13) ◽  
pp. 1573-1579 ◽  
Author(s):  
Divakar Reddy Indukuri ◽  
Gal Reddy Potuganti ◽  
Manjula Alla
Keyword(s):  
Alkali Metal ◽  
Solvent Free ◽  
Heterocyclic Amines ◽  
Ammonium Salts ◽  
Hypervalent Iodine ◽  
Pyrimidine Derivatives ◽  
Reaction Conditions ◽  
Metal Free ◽  
Solvent Free Reaction

A facile, rapid, metal-free regioselective halogenation and thiocyanation of imidazo[1,2-a]pyridine/pyrimidine heterocycles has been achieved under solvent-free reaction conditions. Halogenations and thiocyanation of the heterocycles could be accomplished by simple grinding of reactants and hypervalent iodine reagents with the corresponding alkali metal or ammonium salts. The method has been extrapolated to a cleaner synthesis of brominated imidazo[1,2-a]pyridine/pyrimidine derivatives, starting from the corresponding heterocyclic amines and substituted α-bromoketones, utilising HBr generated in situ as the source of bromine.

Metal-free visible-light-induced oxidative cyclization reaction of 1,6-enynes and arylsulfinic acids leading to sulfonylated benzofurans

2020 ◽  
Vol 31 (1) ◽  
pp. 67-70 ◽  
Author(s):  
Leilei Wang ◽  
Min Zhang ◽  
Yulong Zhang ◽  
Qishun Liu ◽  
Xiaohui Zhao ◽  
...  
Keyword(s):  
Visible Light ◽  
Oxidative Cyclization ◽  
Cyclization Reaction ◽  
Metal Free

Synthesis of visible-light mediated tryptanthrin derivatives from isatin and isatoic anhydride under transition metal-free conditions

2018 ◽  
Vol 5 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Hong Hou ◽  
Hengxue Li ◽  
Ying Han ◽  
Chaoguo Yan
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Isatoic Anhydride ◽  
Reaction Conditions ◽  
Metal Free

Visible light mediated transition metal-free protocol for synthesis of tryptanthrin from isatin and isatoic anhydride in mild reaction conditions.

An I2-catalyzed oxidative cyclization for the synthesis of indolizines from aromatic/aliphatic olefins and α-picoline derivatives

RSC Advances ◽  
2015 ◽  
Vol 5 (37) ◽  
pp. 29424-29427 ◽  
Author(s):  
Likui Xiang ◽  
Fuming Zhang ◽  
Baohua Chen ◽  
Xiaobo Pang ◽  
Xiaodong Yang ◽  
...  
Keyword(s):  
Oxidative Cyclization ◽  
Cyclization Reaction ◽  
Metal Free ◽  
Tandem Cyclization

A novel I2-catalyzed intermolecular oxidative tandem cyclization reaction of aromatic/aliphatic olefins and α-picoline derivatives has been achieved for the synthesis of indolizines under metal-free conditions.

scholarly journals Trichloroacetamidate Triggered Expeditious and Novel Synthesis of N-Acylbenzotriazoles

SynOpen ◽  
2021 ◽  
Author(s):  
Vinod K Tiwari ◽  
MANGAL SINGH YADAV ◽  
Manoj K Jaiswal ◽  
Sunil Kumar
Keyword(s):  
Carboxylic Acids ◽  
Easy Access ◽  
One Pot ◽  
Diverse Range ◽  
Free Condition ◽  
Metal Free ◽  
Activation Pathway ◽  
Novel Synthesis ◽  
Facile Route

A facile route for the synthesis of diverse range of N-acylbenzotriazole derivatives from corresponding carboxylic acids has been established through carbonyl activation pathway. In this method, trichloroacetonitrile is performed as an effective reagent for an easy access of N-acylbenzotriazoles which was simply proceed through the activation of carboxylic acids via in situ imidate formation in anhydrous 1,2 dichloroethane followed by addition of 1H-benzotriazole at 80 oC for 3-4 hours. Easy handling, one-pot, and metal-free condition demonstrate the notable merits of the devised protocol.

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