Efficient preparation method of 4-hydroxybenzoic esters – Oxidation of substituted Hagemman's ester. Issue 23 (7th June 2017)

• Record Type: Journal Article
• Authors: Kang, Sein; Kim, Dahye; In, Ik Joon; Koo, Sangho
• Is Part Of: Tetrahedron letters. Volume 58:Issue 23(2017)
• Page Start: 2264
• Page End: 2266
• Publication Date: 2017-06-07
• Subjects: 4-hydroxybenzoic acids -- Hagemman's ester -- Oxidation -- Aromatization -- Bromination; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2017.04.090
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: Hagemman's esters were prepared by coupling between acetoacetate and aldehydes. Coupling, cyclization, and decarboxylation proceeded in one opt using t -BuOK/ t -BuOH. 4-Hydroxybenzoic esters were synthesized by oxidation of Hagemman's esters. Bromination condition using NBS/TMS·OTf induced oxidation of Hagemman's esters. Abstract: A practical two-step synthetic method of diversely R-substituted 4-hydroxybenzoic esters, which may have wide applications in household chemicals and polymeric materials, was developed by 2:1 coupling between ethyl acetoacetate and aldehydes (RCHO) in t -BuOK/ t -BuOH, followed by oxidative aromatization of the resulting Hagemman's esters. Application of the condition using stoichiometric NBS and catalytic TMS·OTf efficiently induced oxidation of the Hagemman's esters to produce 4-hydroxybenzoic esters.