Highly enantioselective synthesis, crystal structure, and circular dichroism spectroscopy of (R)-bambuterol hydrochloride.
The present article describes the asymmetric synthesis of (R)-bambuterol hydrochloride based on 1-(3,5-dihydroxyphenyl)ethanone as starting material, which was esterified by dimethylcarbamic chloride, and brominated by copper (II) bromide. Then the carbonyl group was reduced efficiently using (-)-B-chlorodiisopinocamphenylborane [(-)-DIP-chloridetrade mark] as an asymmetrical reducing agent. Followed by epoxide ring closure with NaOH and ring expansion with tert-butylamine led to the desired product (R)-bambuterol with e.e. up to 99%. The optical properties and absolute configuration of (R)-bambuterol hydrochloride were further investigated using circular dichroism spectroscopy and X-ray single crystal analysis.
Cao
Gao
G
The School of Chemical and Energy Engineering, South China University of Technology, Guangzhou, Guangdong, People's Republic of China.
Hu
Ai-Xi
AX
Zou
Kang-Sheng
KS
Xu
Ling
L
Chen
Jian-Long
JL
Tan
Wen
W
D000318:Adrenergic beta-Agonists / Q000138:chemical synthesis / Q000737:chemistry; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D011355:Prodrugs / Q000138:chemical synthesis / Q000737:chemistry; D013237:Stereoisomerism; D013726:Terbutaline / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry
D000318:Adrenergic beta-Agonists; D007202:Indicators and Reagents; D011355:Prodrugs; D013726:Terbutaline; C047766:bambuterol