The highly stereoselective intermolecular all-carbon [4+2] annulation between in situ generated acyclic dienolates and α,β-unsaturatedacylazoliums is disclosed. The identification of 2-acyloxy-3-butenones as suitable diene precursors is the key to the success of this transformation. The corresponding highly functionalized cyclohexene products, which are inaccessible from Diels–Alder reactions, were
Synthesis of α,α-Dialkoxy Imines and α-Keto Acetals
作者:Norbert De Kimpe、Elena Stanoeva、Marc Boeykens
DOI:10.1055/s-1994-25491
日期:——
A convenient synthesis of monoacetals of α-diones, i. e. α-keto acetals, was developed by silver ion induced alcoholysis of regiospecifically formed α-bromo-α-chloro ketones. Similarly, the corresponding α,α-dialkoxy ketimines were synthesized from silver ion induced alcoholysis of α-bromo-α -chloro ketimines. Both methods provide an easy access to protected forms of α-diones, useful as building blocks in organic chemistry.
DDQ mediated one step dimerisation of beta-asarone or beta-asarone rich acorus calamus oil in the formation of novel neolignan
申请人:Council of Scientific & Industrial Research
公开号:US20030187306A1
公开(公告)日:2003-10-02
The present invention relates to a novel neolignan (NEOLASA-I) 3-ethyl-2-methyl-3-(2″,4″,5″-trimethoxy-phenyl-1-(2′,4′,5′-trimethoxy)phenyl-1-(2′,4′,5′-trimethoxy)phenyl-1-propene and a process for the preparation of high purity, higher yield neolignan, &agr;-asarone, 2,4,5-trimethoxy-phenyl propionone from &bgr;-asarone or &bgr;-asarone rich
Acorus calamus
oil containing &agr; and &ggr;-asarone by hydrogenating and dimerizing by treatment with DDQ in presence of an organic acid.
DDQ mediated one step dimerization of β-asarone or β-asarone rich Acorus calamus oil in the formation of novel neolignan
申请人:Sinha Arun Kumar
公开号:US06969778B2
公开(公告)日:2005-11-29
The present invention relates to neolignan (NEOLASA-I) 3-ethyl-2-methyl-3-(2″,4″,5″-trimethoxy-phenyl-1-(2′,4′,5′-trimethoxy)phenyl-1-propene and a process for the preparation of high purity, higher yield neolignan, α-asarone, 2,4,5-trimethoxy-phenyl propionone from β-asarone or β-asarone rich
Acorus calamus
oil containing α and γ-asarone by hydrogenating and dimerizing by treatment with DDQ in presence of an organic acid.
Process for 3,4-dimethoxyphenyl-acetone preparation
申请人:LARK S.p.A.
公开号:EP0247526A2
公开(公告)日:1987-12-02
A process for preparing 3,4-dimethoxyphenylacetone is disclosed, which consists in electrolytically epoxidating isoeugenol-methylether in a mixture consisting of water and of a dipolar aprotic solvent, in the presence of Br⁻ ions, and in isomerizing the so-obtained epoxide, in an inert organic solvent, in the presence of catalytic amounts of lithium salts, by means of a heating at temperatures comprised within the range of from 50°C up to the solvent refluxing temperatures.