Despite the key role that carbohydrates play in a wide range of biological processes, the molecular details of carbohydrate-mediated recognition events are not fully understood. In this context, artificial receptors using noncovalent interactions for sugar binding provide useful model systems to study the basic principles of carbohydrate-based molecular recognition processes. The studies in this area are also strongly motivated by the belief that carbohydrate-binding agents could be used for the detection and treatment of diseases. This review covers representative examples of carbohydrate receptors operating through noncovalent interactions, with a focus on developments in receptor systems over the last two years.

The potential of compounds combining both a macrocyclic building block and two hydroxyl-bearing side arms to act as carbohydrate receptors was studied.

The aim of the study was to evaluate the potential of trimethoxybenzene- and trimethylbenzene-based compounds bearing imidazole or indole groups as recognition sites in the complexation of carbohydrates. Representatives of these compounds were prepared and their binding properties toward selected carbohydrates evaluated. The results of the binding studies were compared with those obtained for the prepared pyrrole bearing analogues and for the previously described triethylbenzene-based receptors.

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.

Complexes formed between methyl α-d-glucopyranoside and an artificial receptor represent a valuable source of information about the basic molecular features of carbohydrate recognition.