Photochemistry of the nitro group in aromatic heterocyclic molecules

Aromatic heterocyclic molecules with negative electron affinity values can be transformed to highly oxidizing super/hyperhalogens based on a systematic in silico approach.

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Effects of Ultrasounds on Neat nitrobenzene

Revista de Chimie ◽

10.37358/rc.19.8.7492 ◽

2019 ◽

Vol 70 (8) ◽

pp. 3085-3088

Author(s):

Carmen Eugenia Stavarache ◽

Yasuaki Maeda ◽

Mircea Vinatoru

Keyword(s):

Nitro Group ◽

Radical Cation ◽

Reaction Mechanisms ◽

Diphenyl Ether ◽

Argon Atmosphere ◽

Phenyl Radical ◽

Dissolved Gas ◽

Decomposition Products ◽

Oxygenated Compounds ◽

Phenyl Cation

Neat nitrobenzene was continuously irradiated at two ultrasonic frequencies: 40 and 200 kHz, under air and argon atmosphere, respectively. Samples taken at intervals of 1, 5, 10 and 24 h were analyzed by GC-MS and decomposition products were identified. Possible reaction mechanisms are discussed. Presence of air as dissolved gas leads to oxygenated compounds such as 1,4-benzoquinone, 2,4-dinitrophenol, m-dinitrobenzene while argon inhibits the decomposition of nitrobenzene, especially at sonication times under 5 h. Based on the nature of the compounds identified we advanced a mechanism, involving a divergent splitting of unstable radical cation of NB in air and argon respectively. Thus, under air, the phenyl cation formation is preferred leading to 1,4-benzoquinone nitro-biphenyls and dinitrobenzene, while under argon, the phenyl radical formation seems to be favored, leading to phenol and diphenyl ether. The oxygenated compounds detected under argon clearly are a consequence of the nitro group splitting.

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Synthesis of Drugs and Biorelevant N-heterocycles Employing Recent Advances in C-N Bond Formation

Current Organic Chemistry ◽

10.2174/1385272824999200909114144 ◽

2020 ◽

Vol 24 (20) ◽

pp. 2293-2340

Author(s):

Firdoos Ahmad Sofi ◽

Prasad V. Bharatam

Keyword(s):

Kinase Inhibitors ◽

Bond Formation ◽

Comprehensive Review ◽

Biologically Relevant ◽

Lead Compounds ◽

Heterocyclic Molecules ◽

The Past ◽

Anti Cancer ◽

Modern Methods ◽

Bond Formation Reactions

C-N bond formation is a particularly important step in the generation of many biologically relevant heterocyclic molecules. Several methods have been reported for this purpose over the past few decades. Well-known named reactions like Ullmann-Goldberg coupling, Buchwald-Hartwig coupling and Chan-Lam coupling are associated with the C-N bond formation reactions. Several reviews covering this topic have already been published. However, no comprehensive review covering the synthesis of drugs/ lead compounds using the C-N bond formation reactions was reported. In this review, we cover many modern methods of the C-N bond formation reactions, with special emphasis on metal-free and green chemistry methods. We also report specific strategies adopted for the synthesis of drugs, which involve the C-N bond formation reactions. Examples include anti-cancer, antidepressant, anti-inflammatory, anti-atherosclerotic, anti-histaminic, antibiotics, antibacterial, anti-rheumatic, antiepileptic and anti-diabetic agents. Many recently developed lead compounds generated using the C-N bond formation reactions are also covered in this review. Examples include MAP kinase inhibitors, TRKs inhibitors, Polo-like Kinase inhibitors and MPS1 inhibitors.

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Synthesis, Antiproliferative Activity and Molecular Docking of New Thiazole/Benzothiazole Fused Pyranopyrimidine Derivatives

Letters in Organic Chemistry ◽

10.2174/1570178617666200319114611 ◽

2020 ◽

Vol 17 (12) ◽

pp. 951-958

Author(s):

Pallava Nagaraju ◽

Pedavenkatagari Narayana Reddy ◽

Pannala Padmaja ◽

Vinod G. Ugale

Keyword(s):

Molecular Docking ◽

Cell Lines ◽

Antiproliferative Activity ◽

Aromatic Aldehydes ◽

Human Colon ◽

Docking Studies ◽

Human Colon Cancer ◽

One Pot ◽

Human Embryonic Kidney Cells ◽

Heterocyclic Molecules

A new class of 4H,5H-benzo[4,5]thiazolo[3,2-a]pyrano[2,3-d]pyrimidin-5-one and 5H,6Hpyrano[ 2,3-d]thiazolo[3,2-a]pyrimidin-5-one derivatives were synthesized via the one-pot threecomponent reaction of 2-hydroxy-4H-benzo[4,5]thiazolo[3,2-a]pyrimidin-4-one and 7-hydroxy-5Hthiazolo[ 3,2-a]pyrimidin-5-one to various aromatic aldehydes and malononitrile. This domino transformation involves the formation of pyranopyrimidine ring by the formation of three C–C bonds and one C– O bond a single synthetic operation. As the products precipitate out of the reaction, simple filtration is enough to gather the products, and thus, there is no need for work-up or column-chromatography. The synthesized thiazole/benzothiazole fused pyranopyrimidine derivatives were evaluated for their antiproliferative activity against four cancer cell lines namely DU 145 (prostate cancer), Hela (Human cervical cancer), MDA-MB-231 (breast cancer), HT-29 (Human colon cancer) and normal cell line HEK293 (human embryonic kidney cells). The results demonstrated that synthesized compounds were selective in its cytotoxicity to cancer cells compared to normal cells. Among these compounds, 2-amino-9- methoxy-5-oxo-4-(3,4,5-trimethoxyphenyl)-4H,5H-benzo[4,5]thiazolo[3,2-a]pyrano[2,3-d]pyrimidine- 3-carbonitrile 4i exhibited the most potent antiproliferative activity against the tested cell lines. Molecular docking studies revealed that these active heterocyclic molecules bind selectively in the colchicine binding site of tubulin polymer.

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Metal and Non-Metal Catalysts in the Synthesis of Five-Membered S-Heterocycles

Current Organic Synthesis ◽

10.2174/1570179416666181207144430 ◽

2019 ◽

Vol 16 (2) ◽

pp. 258-275 ◽

Cited By ~ 2

Author(s):

Navjeet Kaur

Keyword(s):

Organic Synthesis ◽

Biological Activities ◽

Reaction Times ◽

Research Field ◽

Environmentally Benign ◽

Metal Catalyst ◽

Efficient Synthesis ◽

Heterocyclic Molecules ◽

The Past ◽

Harsh Conditions

Background:A wide variety of biological activities are exhibited by N, O and S containing heterocycles and recently, many reports appeared for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal and non-metal catalyst has become a highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of S-heterocylces in the presence of metal and non-metal catalyst. The synthesis of five-membered S-heterocycles is described here.Objective:There is a need for the development of rapid, efficient and versatile strategy for the synthesis of heterocyclic rings. Metal, non-metal and organocatalysis involving methods have gained prominence because traditional conditions have disadvantages such as long reaction times, harsh conditions and limited substrate scope.Conclusion:The metal-, non-metal-, and organocatalyst assisted organic synthesis is a highly dynamic research field. For ßthe chemoselective and efficient synthesis of heterocyclic molecules, this protocol has emerged as a powerful route. Various methodologies in the past few years have been pointed out to pursue more sustainable, efficient and environmentally benign procedures and products. Among these processes, the development of new protocols (catalysis), which avoided the use of toxic reagents, are the focus of intense research.

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