Regioselective Synthesis of Some Rhamnopyranoside Esters for PASS Predication, and ADMET Studies

Notable biological activities including brains protective activities have made carbohydrate esters as a topic of great interest over the past several decades. In this context, unimolecular treatment of methyl α-L-rhamnopyranoside (3) with dibutyltin oxide gave the corresponding 2,3-O-(dibutylstannylene) derivative which was then allowed to react with 3-chlorobenzoyl chloride. The reaction regioselectively furnished the 3-O-substitution product 4 in excellent yield. To get newer rhamnopyranoside esters chlorobenzoate 4 was further converted into four 2,4-di-O-substituted products 5-8 with other acylating agents using direct acylation technique. Moreover, thermodynamic properties indicated that these SEs possess better stability, suitable polar nature and higher binding affinity than the non-ester rhamnopyranoside 3. PASS (Prediction of Activity Spectra for Substances) predication showed that these SEs should be more potent against fungal pathogens than the bacterial organisms. With these encouraging results ADMET and drug-likeness properties of the SEs 4-8 are also discussed.