The carboboration of terminal alkynes was studied with a N‐heterocyclic carbene‐capped α‐cyclodextrin copper(I) complex as catalyst. The intermolecular reaction with CH3I gave linear (L) vinyl boron isomers with high selectivity. The intramolecular reaction with terminal alkynes led to exocyclic vinyl boronates and to an unexpected endocyclic (Z)‐isomer, suggesting an unusual mechanism promoted by
Gold(I)-Catalyzed Cyclization–3-Aza-Cope–Mannich Cascade and Its Application to the Synthesis of Cephalotaxine
作者:Takeo Sakai、Chise Okumura、Masatoshi Futamura、Naotaka Noda、Akari Nagae、Chiharu Kitamoto、Madoka Kamiya、Yuji Mori
DOI:10.1021/acs.orglett.1c01323
日期:2021.6.4
The discovery of a new gold(I)-catalyzed cascade reaction involving cyclization onto a vinylammonium, 3-aza-Cope rearrangement, and Mannich cyclization is reported. A variety of fused nitrogen heterocycles were prepared from simple cyclictertiary amines using 1–5 mol % of a AuCl(PPh3)/Ag[C5(CN)5] cocatalyst system. The developed reaction was used in a study aimed at synthesizing cephalotaxine. A five-step
1-substituted-2-(piperazinyl or homopiperazinyl)-benzimidazole compounds
申请人:Kanebo, Ltd.
公开号:US04603130A1
公开(公告)日:1986-07-29
Novel benzimidazole derivatives of the formula: ##STR1## wherein R.sup.1 is a lower alkyl group, a lower alkenyl group or a lower alkynyl group, R.sup.2 is hydrogen atom, a lower alkyl group or a lower hydroxyalkyl group, and n is 2 or 3, or a pharmaceutically acceptable acid addition salt thereof, which have potent antihistaminic activity with less toxicity and hence are useful as an antihistaminics, and a process for the preparation of the compounds, and a pharmaceutical composition useful as antihistaminics containing the compound as an essential active ingredient.
Benzimidazole derivatives, process for the preparation thereof and
申请人:Kanebo, Ltd.
公开号:US04430343A1
公开(公告)日:1984-02-07
Novel benzimidazole derivatives of the formula: ##STR1## wherein R.sup.1 is an alkyl group having 1 to 3 carbon atoms, allyl group, propargyl group, or phenyl group; R.sup.2 is hydrogen atom or an alkyl group having 1 to 3 carbon atoms; and n is 2 or 3, or pharmaceutically acceptable acid addition salts thereof, which have excellent antihistaminic activities and are useful as antiallergics for various allergic diseases, and a process for the preparation thereof, and an antihistaminic composition containing the compound as an active ingredient.