81329-49-9Relevant academic research and scientific papers
Visible-light enabled C4-thiocyanation of pyrazoles by graphite-phase carbon nitride (g-C3N4)
Pan, Junyi,Liu, Cheng,Wang, Jianqiang,Dai, Yunqiao,Wang, Shengyu,Guo, Cheng
supporting information, (2021/07/14)
Thiocyanation is an important and effective way to form C[sbnd]S bonds in organic synthetic methodology. Especially, thiocyanation of pyrazole attracts the attention of many researchers because sulfur-containing compounds are widely applied in many crucial fields such as organic materials, agrochemistry, nanotechnology, etc. Herein, we described A rapid metal- and additive-free method for C(sp2)-H thiocyanation of pyrazoles under visible light at room temperature by using a sustainable catalyst of graphite-phase carbon nitride (g-C3N4) and a thiocyanating agent of ammonium thiocyanate. The method presents many advantages, such as usage of eco-friendly photoredox catalyst, a wide range of substrates and a good yield of products, etc.
Oxone-DMSO Triggered Methylene Insertion and C(sp2)-C(sp3)-H-C(sp2) Bond Formation to Access Functional Bis-Heterocycles
Bharatam, Prasad V.,Dubey, Gurudutt,Hussain, Yaseen,Kour, Jaspreet,Sahoo, Subash C.,Sawant, Sanghapal D.,Venkateswarlu, Vunnam,Verma, Praveen K.
supporting information, p. 4951 - 4962 (2020/05/08)
Metal-free insertion of a methylene group was achieved for the construction of a new C(sp2)-C(sp3)-H-C(sp2) bond in order to prepare novel bis-heterocyclic scaffolds. The complete mechanistic investigations included experimental study and DFT calculations, and various symmetric and unsymmetric bis-pyrazoles as well as other pyrazole-based bis-heterocyclic molecules were prepared in moderate to high yields. Further modification of the bridged methylene group in the unsymmetric pyrazoles generated a chiral center to extend the scope of this method.
Direct N-heterocyclization of hydrazines to access styrylated pyrazoles: synthesis of 1,3,5-trisubstituted pyrazoles and dihydropyrazoles
Venkateswarlu, Vunnam,Kour, Jaspreet,Kumar, K. A. Aravinda,Verma, Praveen Kumar,Reddy, G. Lakshma,Hussain, Yaseen,Tabassum, Aliya,Balgotra, Shilpi,Gupta, Sorav,Hudwekar, Abhinandan D.,Vishwakarma, Ram A.,Sawant, Sanghapal D.
, p. 26523 - 26527 (2018/08/07)
A microwave-assisted method has been developed for the synthesis of tri-substituted pyrazoles via direct N-heterocyclization of hydrazines with metal-acetylacetonate and -dibenzylideneacetonate without using any base or additives. Most importantly, the synthesis of 1-aryl-5-phenyl-3-styryl-1H-pyrazoles was achieved in a single step using hydrochloride salt of various phenylhydrazines and this is the first report for direct construction of these molecules. The reaction medium and microwave conditions play a critical role for their selective product formation during the reaction. The present reaction explored the usage of metal-diketonic complexes as reaction substrates providing acetylacetone and dibenzylideneacetone moieties to directly participate in cyclization with hydrazines to form the corresponding pyrazoles in excellent yields. The present protocol introduces the important N-heterocyclic moieties in the final structures, giving the reaction great applications from a medicinal chemistry perspective, particularly in the late stage modification strategies in drug discovery.
