Facile Hydrogenative Deprotection of N-Benzyl Groups Using a Mixed Catalyst of Palladium and Niobic Acid-on-Carbon

Yuta Yamamoto; Eisho Shimizu; Kazuho Ban; Yoshiyuki Wada; Tomoteru Mizusaki; Masatoshi Yoshimura; Yukio Takagi; Yoshinari Sawama; Hironao Sajiki

doi:10.1021/acsomega.9b03226

Facile Hydrogenative Deprotection of N-Benzyl Groups Using a Mixed Catalyst of Palladium and Niobic Acid-on-Carbon

ACS Omega. 2020 Feb 5;5(6):2699-2709. doi: 10.1021/acsomega.9b03226. eCollection 2020 Feb 18.

Authors

Yuta Yamamoto¹, Eisho Shimizu¹, Kazuho Ban¹, Yoshiyuki Wada², Tomoteru Mizusaki², Masatoshi Yoshimura³, Yukio Takagi³, Yoshinari Sawama¹, Hironao Sajiki¹

Affiliations

¹ Laboratory of Organic Chemistry, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan.
² Catalysts Development Center, N. E. Chemcat Corporation, 25-3 Koshindaira, Bando, Ibaraki 306-0608, Japan.
³ Catalysts Development Center, N. E. Chemcat Corporation, 678 Ipponmatsu, Numazu, Shizuoka 410-0314, Japan.

Abstract

The palladium-on-carbon (Pd/C)-catalyzed hydrogenative deprotection of the N-benzyl-protecting group was effectively facilitated by the combined use of niobic acid-on-carbon (Nb₂O₅/C). Nb₂O₅/C is an acidic heterogeneous catalyst prepared from NbCl₅ and activated carbon. The catalysts were easily removed from the reaction mixture and reusable. Deprotected amines were obtained in excellent yields without an additional neutralization process. The facilitating effect of Nb₂O₅/C was also observed during the Pd/C-catalyzed hydrogenative deprotection of the N-benzyloxycarbonyl (Cbz) and O-benzyl groups.