T. Yamashita, H. Nishikawa, T. Kawamoto
Feb 1, 2019
Citations
0
Influential Citations
5
Citations
Journal
Tetrahedron
Abstract
Abstract Continuous photo flow synthesis of tert-butyl 3-oxo-2-oxabicyclo[2.2.0]hex-5-ene-6-carboxylate (2b) from tert-butyl 2-oxo-2H-pyran-5-carboxylate (1b) has been investigated for scale-up synthesis of cis-3-(tert-butoxycarbonyl)-2,3,4-d3-cyclobutanecarboxylic acid (3c) as a useful building block for preparation of various biologically active compounds and those of material sciences containing cyclobutane ring system(s) labeled with deuterium atoms. Optimization of reaction conditions and modification of the photo flow reaction system have brought about the production of cis-3-(tert-butoxycarbonyl)-2,3,4-d3-cyclobutanecarboxylic acid (3c) with excellent deuterium content in 3.6 g through the continuous photo flow synthesis for 22 h followed by hydrogenation with deuterium gas. Also, application of the product to synthesis of cis-3-((benzyloxycarbonyl)methyl-d2)cyclobutane-1,2,4-d3-carboxylic acid (11) is described for preparation of internal standards of drug candidate compounds in quantitative mass spectrometry analyses in nonclinical and clinical pharmacokinetic studies.