1326316-23-7Relevant academic research and scientific papers
Synthesis of dihydrooxepino[3,2-c]pyrazoles via Claisen rearrangement and ring-closing metathesis from 4-allyloxy-1H-pyrazoles
Usami, Yoshihide,Kohno, Aoi,Yoneyama, Hiroki,Harusawa, Shinya
, (2018)
Synthesis of novel pyrazole-fused heterocycles, i.e., dihydro-1H- or 2H-oxepino[3,2-c] pyrazoles (6 or 7) from 4-allyloxy-1H-pyrazoles (1) via combination of Claisen rearrangement and ring-closing metathesis (RCM) has been achieved. A suitable catalyst fo
Synthesis of dihydropyrano[3,2-c]pyrazoles via double bond migration and ring-closing metathesis
Usami, Yoshihide,Sumimoto, Kodai,Kishima, Azusa,Tatsui, Yuya,Yoneyama, Hiroki,Harusawa, Shinya
, (2019)
Three types of pyrazole-fused heterobicycles, i.e., 1,5-, 1,7-, and 2,5-dihydropyrano[3,2-c] pyrazoles, were synthesized from 4-allyloxy-1H-pyrazoles. A sequence of the Claisen rearrangement of 4-allyloxy-1H-pyrazoles, ruthenium-hydride-catalyzed double b
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.
Divergent synthesis of withasomnines via synthesis of 4-hydroxy-1H- pyrazoles and Claisen rearrangement of their 4-O-allylethers
Ichikawa, Hayato,Watanabe, Ryo,Fujino, Yuiko,Usami, Yoshihide
scheme or table, p. 4448 - 4451 (2011/09/19)
4-Hydroxypyrazoles were synthesized by the alkaline hydrolysis of the Baeyer-Villiger oxidation products of 4-formylpyrazoles. This new synthesis of 4-hydroxypyrazoles was applied to the divergent synthesis of withasomnine alkaloids in a unique strategy, for which the key steps included the regioselective Claisen rearrangement of their 4-O-allyl-4-hydroxy-1H-pyrazoles and a Suzuki coupling of 4-trifluoromethanesulfonyloxy-1H-pyrazoles and arylboronic acids.
