PIFA-Mediated Oxidative Cyclization Reactions of α-Acyl Acrylamides: A Synthetic Route to Substituted Isoxazol-3(2H)-ones

Synthesis ◽  
2018 ◽  
Vol 50 (09) ◽  
pp. 1875-1882 ◽  
Author(s):  
Rui Zhang ◽  
Dewen Dong ◽  
Jingwen Yuan ◽  
Chitturi Rao ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Intramolecular Cyclization ◽  
Oxidative Cyclization ◽  
Metal Catalyst ◽  
Synthetic Route ◽  
Cyclization Reactions ◽  
Reaction Conditions ◽  
Catalyst Free ◽  
Free Oxidation

An intramolecular cyclization of various α-acyl β-amino acrylamides in the presence of PIFA and TFA is described. This transformation features mild reaction conditions, simple execution, high chemo­selectivity, and metal catalyst-free oxidation, and thereby, provides not only an alternative protocol for the construction of N–O bond, but also an efficient and straightforward synthesis of substituted isoxazol-3(2H)-ones from readily available α-acyl acrylamides.

Diversity-Oriented Synthesis via Catalyst-Free Addition of Ketones to [e]-Fused 1H-Pyrrole-2,3-diones

Synthesis ◽  
2018 ◽  
Vol 50 (24) ◽  
pp. 4897-4904 ◽  
Author(s):  
Ekaterina Stepanova ◽  
Andrey Maslivets ◽  
Svetlana Kasatkina ◽  
Maksim Dmitriev
Keyword(s):  
Intramolecular Cyclization ◽  
Aromatic Hydrocarbons ◽  
Michael Addition ◽  
Aldol Reaction ◽  
Synthetic Approach ◽  
Reaction Conditions ◽  
Diversity Oriented Synthesis ◽  
Catalyst Free ◽  
Solvent Free Conditions ◽  
Reaction Proceeds

A facile synthetic approach towards two distinct pyrrole-based heterocyclic scaffolds has been developed by the interaction of 1H-pyrrole-2,3-diones fused at the [e]-side to a 1,4-benzoxazin-2-one or quinoxalin-2(1H)-one moiety with ketones. The described interaction proceeds either as an aldol reaction or as a Michael addition/intramolecular cyclization depending on the reaction conditions. The disclosed aldol reaction proceeds with good diastereoselectivity under catalyst-free conditions when the reaction is carried out in aromatic hydrocarbons. Products of the cascade Michael addition/intramolecular cyclization reaction are predominantly formed under catalyst-free and solvent-free conditions. The proposed strategy provides facile access to pharmaceutically interesting pyrrole-based polyheterocycles.

Iron-Promoted Construction of Indoles via Intramolecular Oxidative C–N Coupling of 2-Alkenylanilines Using Persulfate

Synthesis ◽  
2019 ◽  
Vol 51 (16) ◽  
pp. 3085-3090
Author(s):  
Menglan Wang ◽  
Yudong Li ◽  
Qing-An Wu ◽  
Shuping Luo ◽  
Yuehui Li
Keyword(s):  
Intramolecular Cyclization ◽  
Synthetic Route ◽  
Cyclization Reactions ◽  
Wide Range ◽  
First Time ◽  
Drug Intermediates

Indole scaffold synthesis relies primarily on oxidative C–H amination of N-protected alkenylanilines for C–N intramolecular cyclization reactions. Herein, for the first time, without N-protection, various readily prepared 2-alkenylanilines were transformed into the desired indole products in good yields by using K2S2O8 as oxidant in the presence of catalytic amounts of FeF2. The K2S2O8/FeF2 system offers a direct and benign synthetic route to 3-arylindoles and it is applicable to a wide range of substituted indoles including drug intermediates.

Access to pyrrole-based heterocyclic compounds via addition of pyrrole to C=C and C=N bonds

2014 ◽  
Vol 86 (6) ◽  
pp. 925-932 ◽  
Author(s):  
Canan Unaleroglu ◽  
Baris Temelli ◽  
Dilek Isik Tasgin
Keyword(s):  
Intramolecular Cyclization ◽  
Heterocyclic Compounds ◽  
The Other ◽  
Addition Reactions ◽  
Cyclization Reactions ◽  
Reaction Conditions ◽  
Unsaturated Compounds ◽  
Intermolecular Cyclization

AbstractA series of metal triflate-catalyzed addition reactions of pyrrole to C=C and C=N bonds have been investigated to access pyrrole-based heterocyclic compounds. The addition of pyrrole to different α,β-unsaturated compounds or N-tosyl imines afforded suitable structures for the construction of [5-5] bicyclic systems or porphyrins, respectively. Intramolecular cyclization reactions were applied for the synthesis of pyrrolizine derivatives. In the other reaction mode, intermolecular cyclization reactions gave A4- and trans-A2B2-meso-substituted porphyrins under mild reaction conditions with low scrambling.

Visible Light Assisted Synthesis of 5-Aryl-1,2,4-thiazolidine-3-thiones Under Catalyst-free Condition

2020 ◽  
Vol 7 (3) ◽  
pp. 326-333
Author(s):  
Amol Khandebharad ◽  
Swapnil Sarda ◽  
Pravin Kulkarni ◽  
Brijmohan Agrawal
Keyword(s):  
Present Method ◽  
Metal Catalyst ◽  
Reaction Conditions ◽  
One Pot ◽  
Free Condition ◽  
Short Reaction Time ◽  
Mechanical Stirring ◽  
Catalyst Free ◽  
Integrated Technique ◽  
The Impact

Abstract: Light energy can be considered as an ideal eco-friendly source of energy for green chemistry. This perspective was used to synthesize 5-aryl-1,2,4-thiazolidine-3-thiones derivative as a quick, efficient and highly improved protocol. The present method developed an energy competent and integrated technique by one-pot condensations of aromatic aldehyde and thiosemicarbazide under the catalyst-free condition in aqueous-alcoholic media. The impact of light on reaction along with mechanical stirring provided a prominent yield of the product. The mild reaction conditions, short reaction time and easy workup procedure, avoidance of heavy metal catalyst and harsh reaction conditions make this protocol greener.

Convenient and Clean Synthesis of Isatins by Metal-Free Oxidation of Oxindoles

Synlett ◽  
2017 ◽  
Vol 28 (17) ◽  
pp. 2307-2310 ◽  
Author(s):  
Wen-Ting Wei ◽  
Hongze Liang ◽  
Wei-Wei Ying ◽  
Wen-Ming Zhu ◽  
Yi Wu ◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Synthetic Route ◽  
Reaction Conditions ◽  
Metal Free ◽  
Tert Butyl ◽  
Convenient Procedure ◽  
Oxidative Reactions ◽  
Clean Synthesis ◽  
Free Oxidation

A metal-free synthesis of isatins was achieved through the oxidative reactions of oxindoles with molecular oxygen in the presence of tert-butyl nitrite as an additive. This strategy provides a convenient and simple synthetic route to the construction of C=O bonds without the need for any catalyst or base. The attractive features of this reaction include its convenient procedure and mild reaction conditions.

Attempts to Mimic Key Bond-Forming Events Associated with the Proposed Biogenesis of the Pentacyclic Lamellarins

2008 ◽  
Vol 61 (2) ◽  
pp. 80 ◽  
Author(s):  
Lorraine C. Axford ◽  
Kate E. Holden ◽  
Katrin Hasse ◽  
Martin G. Banwell ◽  
Wolfgang Steglich ◽  
...  
Keyword(s):  
Carboxy Group ◽  
Pyrrole Ring ◽  
Lactone Ring ◽  
Polymeric Materials ◽  
Isoquinoline Alkaloid ◽  
Oxidative Cyclization ◽  
Analogous Reaction ◽  
Cyclization Reactions ◽  
Reaction Conditions ◽  
Bond Forming

The pyrrole-tethered veratroles 16 and 27 each engage in PIFA-induced oxidative cyclization reactions to give compounds 22 and 29, respectively, which incorporate a key tricyclic fragment associated with the title natural products. In contrast, the corresponding catechols 11 and 12 only produce polymeric materials on subjection to analogous reaction conditions. Efforts to study lactone ring formation by the oxidative cyclization of catechol 30 and veratrole 38 have been thwarted by an inability to prepare the former substrate and decomposition of the latter. The reported conversions 44 → 45 and 46 → 47 suggest that a C2-carboxy group attached to the pyrrole ring can ‘direct’ the oxidative cyclization of N-tethered aryl groups. The acquisition of compound 22 by the means described herein provides an adventitious and concise route to the racemic modification of the pyrrolo[2,1-a]isoquinoline alkaloid crispine A (52).

Synthesis of 6-phenylbenzo[h]quinolines via photoinduced dehydrogenative annulation of (E)-2-phenyl-3-styrylpyridines

2021 ◽  
Vol 19 (39) ◽  
pp. 8554-8558
Author(s):  
Lixin Niu ◽  
Yun He ◽  
Jin Xi ◽  
Tao Wang ◽  
Yong Liang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Efficient Method ◽  
Metal Catalyst ◽  
Reaction Conditions ◽  
Transition Metal Catalyst ◽  
Simple Operation ◽  
Catalyst Free ◽  
Free Process

A efficient method for the synthesis of 6-phenylbenzo[h]quinolines 2 has been developed. This strategy has the prominent advantages of simple operation, mild reaction conditions, high atom efficiency, and transition-metal/catalyst-free process.

Novel One-pot Synthesis of Pyranocarbazole Derivatives via an Isocyanide-based Three-component Reaction

2020 ◽  
Vol 17 ◽  
Author(s):  
Visarapu Malathi ◽  
Pedavenkatagari Narayana Reddy ◽  
Pannala Padmaja
Keyword(s):  
Efficient Method ◽  
Atom Economy ◽  
Reaction Conditions ◽  
One Pot ◽  
Catalyst Free ◽  
One Pot Synthesis ◽  
Three Component Reaction ◽  
High Yields

Abstract:: An efficient method has been developed for the synthesis of new pyrano[3,2-c] and pyrano[3,2-a]carbazole de-rivatives via a three component reaction of 4-hydroxycarbazole or 2-hydroxycarbazole, isocyanides, and dialkylacetylenedi-carboxylates. Noteworthy features of this protocol include mild reaction conditions, catalyst-free, high atom-economy and high yields.

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