1326316-18-0Relevant academic research and scientific papers
Cui-catalyzed coupling reactions of 4-iodopyrazoles and alcohols: Application toward withasomnine and Homologs
Harusawa, Shinya,Hayama, Noboru,Kubo, Yumika,Kuroiwa, Nao,Nakamizu, Ayaka,Nishikawa, Kohei,Ono, Jun,Takagaki, Toshiki,Tatsui, Yuya,Usami, Yoshihide,Yoneyama, Hiroki
, (2021)
The direct 4-alkoxylation of 4-iodo-1H-pyrazoles with alcohols was achieved by a CuIcatalyzed coupling protocol. The optimal reaction conditions employed excess alcohol and potassium t-butoxide (2 equiv) in the presence of CuI (20 mol%) and 3,4,7,8-tetramethyl-1,10-phenanthroline (20 mol%) at 130 °C for 1 h under microwave irradiation. The present method was efficiently applied to the synthesis of withasomnine and its six- and seven-membered cyclic homologs.
Divergent synthesis and evaluation of inhibitory activities against cyclooxygenases-1 and -2 of natural withasomnines and analogues
Usami, Yoshihide,Watanabe, Ryo,Fujino, Yuiko,Shibano, Makio,Ishida, Chihiro,Yoneyama, Hiroki,Harusawa, Shinya,Ichikawa, Hayato
, p. 1550 - 1560 (2013/02/22)
The divergent synthesis of natural withasomnines and analogues was achieved from 4-hydroxypyrazoles, which was prepared via alkaline hydrolysis of the Baeyer-Villiger oxidation products from 4-formylpyrazoles. Key steps of this synthesis are regioselective Claisen rearrangement of 4-allyloxypyrazoles and the Suzuki-Miyaura coupling of 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazol-3-yl trifluoromethanesulfonate and commercially available arylboronic acids. The Suzuki-Miyaura coupling at the final step of this strategy enabled facile access to natural withasomnines and their analogues. The biological activities of the twelve synthesized compounds against cyclooxygenases-1 and -2 (COX-1 and COX-2) were evaluated.
