ChemInform Abstract: QUINAZOLINES AND 1,4-BENZODIAZEPINES. 81. S-TRIAZOLO(4,3-A)(1,4)BENZODIAZEPINES BY OXIDATIVE CYCLIZATION OF HYDRAZONES

1978 ◽  
Vol 9 (16) ◽  
Author(s):  
A. WALSER ◽  
G. ZENCHOFF
Author(s):  
Xiao-Feng Wu ◽  
Zhengkai Chen ◽  
Jiajun Zhang ◽  
Tian-Hui Xu

A metal-free oxidative cyclization of trifluoroacetimidohydrazides with methylhetarenes for the efficient synthesis of 3-hetaryl-5-trifluoromethyl-1,2,4-triazoles has been developed. Notable features of this protocol include readily accessible starting materials, a broad substrate...


2021 ◽  
Vol 2021 (6) ◽  
pp. 951-955
Author(s):  
Zhiwei Chen ◽  
Guang Shi ◽  
Wei Tang ◽  
Jie Sun ◽  
Wenxing Wang

2021 ◽  
Vol 13 (5) ◽  
pp. 6349-6358
Author(s):  
Zainab Almansaf ◽  
Jiyun Hu ◽  
Federica Zanca ◽  
Hamid R. Shahsavari ◽  
Benjamin Kampmeyer ◽  
...  

Synthesis ◽  
2021 ◽  
Author(s):  
Stefan H. Bossmann ◽  
Raul Neri

AbstractIsoselenocyanates (ISCs) are a class of organoselenium compounds that have been recognized as potential chemotherapeutic and chemopreventative agents against cancer(s) and infectious diseases. ISC compounds are chemically analogous to their isosteric relatives, isothiocyanates (ITCs); however, they possess increased biological activity, such as enhanced cytotoxicity against cancer cells. ISCs not only serve as significant products, but also as precursors and essential intermediates for a variety of organoselenium compounds, such as selenium-containing heterocycles, which are biologically active. While syntheses of ISCs have become less difficult to accomplish, the syntheses of selenium-containing heterocycles are often difficult due to the use of highly toxic selenium reagents. Because of this, ISCs can serve as versatile reagents for the preparation of these heterocycles. In this review, the classical and recent syntheses of ISCs will be discussed, along with notable and recent synthetic work employing ISCs to access novel selenium-containing heterocycles.1 Introduction1.1 Selenium and Health2 Isoselenocyanates2.1 Preparation of Isoselenocyanates3 Selenium-Containing Heterocycles3.1 Notable Synthetic Work3.2 Recent Synthetic Work3.2.1 Synthesis of N-(3-Methyl-4-phenyl-3H-selenazol-2-ylidene)benzamide­ Derivatives3.2.2 Synthesis and X-ray Studies of Diverse Selenourea Derivatives3.2.3 Synthesis of Heteroarene-Fused [1,2,4]Thiadiazoles/Selenadiazoles via Iodine-Promoted [3+2] Oxidative Cyclization3.2.4 2-Amino-1,3-selenazole Derivatives via Base-Promoted Multicomponent Reactions4 Conclusion


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4415
Author(s):  
Sergey A. Usachev ◽  
Diana I. Nigamatova ◽  
Daria K. Mysik ◽  
Nikita A. Naumov ◽  
Dmitrii L. Obydennov ◽  
...  

A convenient and general method for the direct synthesis of 2-aryl-6-(trifluoromethyl)-4-pyrones and 2-aryl-5-bromo-6-(trifluoromethyl)-4-pyrones has been developed on the basis of one-pot oxidative cyclization of (E)-6-aryl-1,1,1-trifluorohex-5-ene-2,4-diones via a bromination/dehydrobromination approach. This strategy was also applied for the preparation of 2-phenyl-6-polyfluoroalkyl-4-pyrones and their 5-bromo derivatives. Conditions of chemoselective enediones bromination were found and the key intermediates of the cyclization of bromo-derivatives to 4-pyrones were characterized. Synthetic application of the prepared 4-pyrones has been demonstrated for the construction of biologically important CF3-bearing azaheterocycles, such as pyrazoles, pyridones, and triazoles.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chengshuo Shen ◽  
Guoli Zhang ◽  
Yongle Ding ◽  
Na Yang ◽  
Fuwei Gan ◽  
...  

AbstractNanographenes are emerging as a distinctive class of functional materials for electronic and optical devices. It is of remarkable significance to enrich the precise synthetic chemistry for these molecules. Herein, we develop a facile strategy to recompose helicenes into chiral nanographenes through a unique oxidative cyclo-rearrangement reaction. Helicenes with 7~9 ortho-fused aromatic rings are firstly oxidized and cyclized, and subsequently rearranged into nanographenes with an unsymmetrical helicoid shape through sequential 1,2-migrations. Such skeletal reconstruction is virtually driven by the gradual release of the strain of the highly distorted helicene skeleton. Importantly, the chirality of the helicene precursor can be integrally inherited by the resulting nanographene. Thus, a series of chiral nanographenes are prepared from a variety of carbohelicenes and heterohelicenes. Moreover, such cyclo-rearrangement reaction can be sequentially or simultaneously associated with conventional oxidative cyclization reactions to ulteriorly enrich the geometry diversity of nanographenes, aiming at innovative properties.


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