New route for synthesis of 3- and 5-caffeoylquinic acids via protected quinic acids

Abstract

Caffeoylquinic acids (CQAs) are a group of the phenylpropanoids produced by certain plant species, which have various biological activities including antioxidant, antibacterial, anticancer, and others. Several synthetic routes have been developed using quinic acids (QAs) and caffeic acid derivatives as starting materials. In this study, alternative pathways of 3-and 5-CQAs preparation using protected quinic acids are described. Both CQAs were achieved by removal of the protecting groups of compound 9 and 18 with acid hydrolysis using dilute HCl solution. These compounds (9 and 18) are novel, resulted from esterification reaction of diacetyl caffeoyl chloride and protected quinic acids. The hydroxyl groups of quinic acid in this case were protected with 2,2-dimethoxy propane or tert-butyldimethylsilyl (TBS) chloride.

Current Advances in Naturally Occurring Caffeoylquinic Acids: Structure, Bioactivity, and Synthesis

“…Interestingly, in 2013, Dokli et al reported the synthesis of 3-, 4-, and 5-feruloylquinic acids, and their strategy was not obviously different from the method by Sefkow, especially on protected quinic acids (figure not shown). In 2015, Kadidae et al reported a convenient method to synthesis 5-CQA ( 9 ) (Scheme ). The authors used lactone ( 122 ) as a raw material.…”

“…Scheme 2. Synthesis of 1-CQA (1), 3-CQA (2), and 4-CQA (6) et al 183 reported a convenient method to synthesis 5-CQA (9) (Scheme 1). The authors used lactone (122) as a raw material.…”

“…Interestingly, in 2015, Kadidae et al 183 demonstrated that changing the reaction temperature condition could trigger the selective hydroxyl protection of TBSCl in the process of preparing 3-CQA (2) and 4-CQA (6) (Scheme 3). At a high temperature, the protection of the hydroxyl group at C-4 was favorable, while at a low temperature, the 3 position with the protection of the hydroxyl group at C-3 was dominant.…”

“…Overview of the different synthetic strategies to protect quinic acid and caffeic acid.Scheme 1. Synthesis of 5-CQA (9)180,181,183…”

Advances in Production of Hydroxycinnamoyl-Quinic Acids: From Natural Sources to Biotechnology

“… Chemical synthesis of 1-CQA, 3-CQA, 3-CQA and 5-CQA. Selected reactions with highest yields reported by [ 127 ] (1); [ 130 ] (2); [ 126 ] (3–5); and [ 129 ] (6). All reactions performed at room temperature.…”