Regioselective, One-Pot, Three-Component Synthesis of 1,3,4- and 1,3,5-Triarylpyrazoles from 1- and 2-Aryl-1-alkenyl Sulfones

• Published in: European journal of organic chemistry Vol. 2015; no. 21; pp. 4756 - 4764
• Main Authors: Fuse, Shinichiro, Sugiyama, Hirotaka, Kobayashi, Daisuke, Iijima, Yusuke, Matsumura, Keisuke, Tanaka, Hiroshi, Takahashi, Takashi
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01-07-2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Cyclization; Multicomponent reactions; Nitrogen heterocycles; Synthetic methods
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201500562

A one‐pot, three‐component coupling of aldehydes with hydrazines and 1‐aryl‐1‐alkenyl sulfones or 2‐aryl‐1‐alkenyl sulfones for the regioselective synthesis of 1,3,4‐ and 1,3,5‐triarylpyrazoles was developed. In our developed procedure, 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone (DDQ) worked as an effective oxidant, and the addition of an strong acid was not necessary. We synthesized 1,3,4‐ and 1,3,5‐triarylpyrazoles containing acid‐labile functionalities in a one‐pot reaction in good yields.
One‐pot, three‐component couplings of aldehydes with hydrazines and arylalkenyl sulfones for the regioselective syntheses of 1,3,4‐ and 1,3,5‐triarylpyrazoles were demonstrated. In our developed procedure, DDQ worked as an effective oxidant, and the addition of a strong acid was not required. This allowed the synthesis of various pyrazoles in good yields.