A concise approach to the synthesis of homobenzotetramisole and derivatives is described. Our strategy features a one-pot acylation-cyclization of 2-aminobenzothiazole with α,β-unsaturated acid chlorides to afford annulated pyrimidones. Subsequent Grignard addition followed by acid-promoted dehydration and reduction provides good overall yields of the title compounds in three steps and in quantities up to 10 g. The synthesis employs low-cost and readily available starting materials and enables access to both optical antipodes of these increasingly useful nucleophilic catalysts following chiral separation.
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Highly Sensitive, Simple, and Cost- and Time-Effective Method to Determine the Absolute Configuration of a Secondary Alcohol Using Competing Enantioselective Acylation Coupled with LC/MS.
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The absolute-configuration determination of natural products and synthetic compounds with stereogenic centers is very important because stereoisomers dramatically and differentially affect many crucial properties, such as physical behaviors and biological functions. Despite several established methods for determining the absolute configuration, significant unmet needs for new methods still exist owing to the specific limitations of established methodologies. Here, we present a simple, optimized, new chemical-derivative method that utilizes competing enantioselective acylation followed by LC/MS analysis, and we demonstrate its successful application in determining the absolute configuration of a secondary alcohol in natural products with multiple reactive functional groups.
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