Commercially available ethyl isonipecotate (278) was alkylated with 1-bromo-2-chloroethane in the presence of K2CO3 in acetone to give ethyl 1-(2-chloroethyl)piperidine-4-carboxylate (279). This material was then treated with lithium diisopropylamine (LDA) in THF to affect a transannular substitution reaction resulting in the cyclized quinuclidine 280 in 96% yield. Excess of phenyllithium was added to ester 280 in THF starting at low temperature then gradually warming to room temperature to give tertiary alcohol 281 in 61% yield. Amine 281 was finally alkylated with benzyl 2- bromoethyl ether (282) in MeCN/CHCl3 at elevated temperatures to afford umeclidinium bromide (XXXV) in 69% yield. |
Features of Pentyl Bromide Product Name: Pentyl bromide Chemical Formula: C5H11Br CAS No.: 110-53-2 Dangerous Grade: 3 Technical Data of n pentyl bromide Physical State: Liquid Color: clear colorless to faint yellow Odor: None reported. pH: Not available Vapor Pressure: Not ...
Features of Ethyl Bromide Product Name: Ethyl Bromide Chemical Formula: C2H5Br 74-96-4 Dangerous Grade: 6.1 Technical Data of Ethyl Bromide Item Specification Appearance Colorless clear liquid Purity ≥99.0% Water Content ≤500ppm PH 6.0-8.0 Package and Storage: 200kg/drum ...
Features of Propyl Bromide Product Name: 1-Bromopropane Chemical Formula: C3H7Br CAS 106-94-5 Dangerous Grade: 3 Technical Data of Propyl Bromide Item Specification Appearance Colorless Transparent Liquid Assay ≥99.0% Water Content ≤500ppm PH 6.0-8.0 Package and Storage: ...