Conformation, optical properties, and absolute configuration of 2′,3′-isopropylideneadenosines: Theoretical vs. experimental study

The conformational analysis, determination of absolute configurations (ACs) as well as elucidation of the electronic absorption and CD spectra of chiral molecules 2′,3′-O-isopropylideneadenosine (1), 5′-carboxy-2′,3′-O-isopropylidene-D-adenosine (2), 2-chloro-2′,3′-O-isopropylideneadenosine-5′-N- ethylcarboxamide (3) and 1-[6-(6-Amino-2-methyl-purin-9-yl)-2,2-dimethyl-tetrahydro-furo[3,4-d][1,3]dioxol-4-ylmethyl]-3-carbamoyl-pyridinium chloride (4), 9-(6-aminomethyl-2,2-dimethyl-tetrahydro-furo[3,4-d][1,3]dioxol-4-yl)-9H-purin-6-ylamine (5) and acetic acid 6-(6-amino-purin-9-yl)-2,2-dimethyl-tetrahydro-furo[3,4-d][1,3]dioxol-4-ylmethyl ester (6) are performer. The methods such as electronic absorption (EAs), diffuse reflectance (DSs) spectroscopy as well as electronic circular dichroism (ECD) are applied. The theoretical density functional theory (DFT) calculations are carried out to evaluate the optical phenomena of isolated molecules as well as dimeric associates. We are demonstrated the significance and the advances of the stereo chemical experimental and theoretical characterization of natural products and their functional synthetic derivatives, vitha a view to further elucidation of unknown extracts of same chemical class. Special attention is devoted to the role of intermolecular interactions in condense phases on the theoretical and experimental optical properties, studying the corresponding dimeric associates. These results are a key in the drug discovery, and structure-based design of functionalized nucleosides. The methods as single crystal X-ray diffraction and MALDI Orbitrap mass spectrometric imaging (MALDI Orbitrap MSI) are also applied.