ISOLATION AND IDENTIFICATION OF PRODUCTS IN THEREACTION OF 2-ACETAMIDO-3,4,6-TRI-O-ACETYL-1,5-ANHYDRO-2-DEOXY-D-arabino-HEX-1-ENITOL WITH THEOPHYLLINE

Article abstract of DOI:10.1016/S0008-6215(00)80523-6

Fusion of 2-acetamido-3,4,6-tri-O-acetyl-1,5-anhydro-2-deoxy-D-arabino-hex-1-enitol with theophylline, in the presence of boron trifluoride etherate as the catalyst, caused condensation to occur.This reaction afforded a variety of products of nucleosidic character, which were successively separated by repated chromatography on silica gel.The structures of the products were determined, on the basis of X-ray crystallographic analysis ( for three compounds ) and by means of n.m.r.-spectral data and mass spectrometry, as following: 7-(2-acetamido-4,6-di-O-acetyl-2,3-dideoxy-β-D-erythro-hex-2-enopyranosyl)theophylline, the corresponding α- and β-D-threo derivatives, and 7-(2-acetamido-6-O-2,3-dideoxy-α-D-threo-hex-2-enopyranosyl)theophylline and its β anomer.In addition to these 2',3'-unsaturated nucleosides having the base linked at C-1', three products of a new type, having the base attached at C-4', were also isolated: 7-(methyl 2-acetamido-6-O-acetyl-2,3,4-trideoxy-β-D-erythro-hex-2-enopyranosid-4-yl)theophylline, and the corresponding α-D-threo and α-D-erythro isomers.The correlation of the data obtained by X-ray structure analysis and proton nuclear magnetic spectroscopy, together with their application for the determination of configuration of these compounds, are discussed.It appears that the 1H-n.m.r. data alone do not suffice for unambiguous and correct structure determination for these classes of compounds.