Purine Unit as a Building Block of Artificial Receptors Designed for the Recognition of Carbohydrates

Abstract

1,3,5‐Substituted 2,4,6‐triethylbenzene derivatives bearing pyridine/pyrimidine and purine units were synthesized and their potential to function as carbohydrate receptors was evaluated. Compounds consisting of 2‐chloro‐9H(7H)‐purin‐6‐yl unit have the ability to act both as carbohydrate‐binding agents and as a basis for further functionalisation through the nucleophilic displacement of the chlorine atom. Microwave‐assisted reactions and/or the application of sealed tubes allowed the preparation of derivatives with a varying substituent pattern on the purine ring. The relatively drastic reaction conditions required for the successful functionalisation reflect the unfavorable influence of the bulky C6‐substituent on the nucleophilic substitution at purine C2. Initial binding studies towards carbohydrates showed that the properties of this type of purine‐bearing compounds can be fine‐tuned by the variation of the C2‐substituent of the purine ring and represents a valuable basis for the identification of new structure‐activity relationships. Such findings are of high importance for further developments in the area of molecular recognition of carbohydrates by artificial receptors.