Xin Liu, Yu Liu, Huili He
Feb 16, 2014
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0
Influential Citations
3
Citations
Journal
Synthetic Communications
Abstract
Abstract An efficient process for the preparation of (1S)-4,5-dimethoxy-1-[(methylamino)methyl] benzocyclobutane (S)-3 as ivabradine intermediate, which was obtained in 56% yield, is described. The salient feature of this process is the racemization of the undesired (1R)-4,5–dimethoxy-1,2-dihydrocyclobutabenzene-1-carboxylic acid (R)-12, and the overall yield of (S)-12 was improved to 70% by three resolutions of the racemized acid with R-(α)-phenylethanamine. The reduction of amide (S)-13 was achieved with NaBH4-I2 in refluxing tetrahydrofuran, giving the corresponding amine (S)-3 in 90% yield. The improved synthetic route described herein is cost-efficient, environmentally friendly and feasibile for scale-up production. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] GRAPHICAL ABSTRACT