Synthesis of first generation of poly (alkyl aryl ether) dendrimer using hexasubstituted benzene core structure

Abstract

The synthesis of hexasubstituted benzene derivatives towards a dendrimer is the main focus of this research. 1,3,5-Triformyl-2,4,6-trihydroxybenzene 28 was synthesized by Reimer-Tiemann reaction using the phloroglucinol starting material reacting with dichlorocarbene generated from sodium hydroxide and chloroform. After hydrolysis, compound 28 was obtained in 59% yield. 1,3,5-Triacetyl-2,4,6-trihydroxybenzene 29 was synthesized using phloroglucinol reacting with acetyl chloride which went through triple O-acylations and then Fries rearrangement to become the desired product in 85% yield. Compound 29 was modified into the ababab geometry by alkylations on the phenolic hydroxy groups, giving compounds 30, 31, 32 and 33 in 75, 65, 56 and 44% yields, respectively. The potential first generation of poly(alkyl aryl ether) dendrimer 44 was obtained from the reaction of compound 32 with 3,5-dimethoxyphenol followed by demethylations to provide a mixture of products.