Synthesis of 3-Cyanopyrazoles from 3-Trifluoromethyl-pyrazoles via Direct Ammonolysis Reaction
摘要:
A simple and green method to prepare 3-cyanopyrazoles in aqueous ammonia from easy-obtained 3-trifluoromethyl-pyrazoles was explored. Most substrates got acceptable yields. The hydrogen position of Nl-H on cyanopyrazoles was assigned by X-ray crystal structure analysis.
Silver-Mediated Cycloaddition of Alkynes with CF<sub>3</sub>CHN<sub>2</sub>: Highly Regioselective Synthesis of 3-Trifluoromethylpyrazoles
作者:Feng Li、Jing Nie、Long Sun、Yan Zheng、Jun-An Ma
DOI:10.1002/anie.201301870
日期:2013.6.10
Silver screen: The title reaction provides a convenient and efficient method for the construction of 5‐substituted 3‐trifluoromethylpyrazoles under mild reaction conditions. By using this protocol, the marketed drug Celecoxib (antiarthritic) could be easily synthesized (see scheme; DMF=N,N‐dimethylformamide).
is reported that occurs by the three-component coupling of environmentally friendly and large-tonnage industrial feedstock 2-bromo-3,3,3-trifluoropropene (BTP), aldehydes, and sulfonylhydrazides. This highly regioselective three-component reaction is metal-free, catalyst-free, and operationally simple and features mild conditions, a broad substrate scope, high yields, and valuable functional group
Cycloaddition of Trifluoroacetaldehyde <i>N</i>-Triftosylhydrazone (TFHZ-Tfs) with Alkynes for Synthesizing 3-Trifluoromethylpyrazoles
作者:Hongwei Wang、Yongquan Ning、Yue Sun、Paramasivam Sivaguru、Xihe Bi
DOI:10.1021/acs.orglett.0c00395
日期:2020.3.6
(TFHZ-Tfs) and alkynes is reported. This protocol provides an operationally simple and general method for the synthesis of diverse 3-trifluoromethylpyrazoles in good to excellent yields with broad substrate scope, including aryl, heteroaryl, and alkyl terminalalkynes, and electron-deficient internalalkynes. The synthetic potential of this method was further demonstrated by the synthesis of an antiarthritic
A Unified Continuous Flow Assembly-Line Synthesis of Highly Substituted Pyrazoles and Pyrazolines
作者:Joshua Britton、Timothy F. Jamison
DOI:10.1002/anie.201704529
日期:2017.7.17
molecular diversity in short order. Continuous flowsynthesis enables the safe handling of diazoalkanes at elevated temperatures, and the use of aryl alkyne dipolarphiles under catalyst-free conditions. This assembly-line synthesis provides a flexible approach for the synthesis of agrochemicals and pharmaceuticals, as demonstrated by a four-step, telescoped synthesis of measles therapeutic, AS-136A, in a total
A highly selective and efficient method for the synthesis of 5-trifluoromethylated and 5-perfluoroalkylated pyrazoles has been developed which relies on the cyclization of hydrazine dianions with ethyl perfluorocarboxylates. The pyrazoles prepared were evaluated as potential inhibitors of alkaline phosphatases, namely human tissue non-specific alkaline phosphatase (h-TNAP) and tissue specific intestinal