Homologated analogues 3a and 3b of potent and selective A3 adenosine receptor ligands, IB-MECA and dimethyl-IB-MECA were synthesized from commercially available 1-O-acetyl-2,3,5-tri-O-benzoyl-β-d-ribofuranose (4) via Co2(CO)8-catalyzed siloxymethylation as a key step. Unfortunately, homologated analogues 3a and 3b did not show significant binding affinities at three subtypes of adenosine receptors, indicating that free rotation, resulting from homologation, induced unfavorable interactions in the binding site of the receptor maybe due to the presence of many conformations.

中文翻译：

---

合成和作为A3腺苷受体配体的同化腺苷类似物的结合亲和力。

有效和选择性的A3腺苷受体配体IB-MECA和二甲基-IB-MECA的同源类似物3a和3b由市售的1-O-乙酰基-2,3,5-三-O-苯甲酰基-β-d-合成呋喃核糖（4）通过Co2（CO）8催化的甲硅烷氧基甲基化是关键步骤。不幸的是，同源的类似物3a和3b在腺苷受体的三种亚型上没有显示出显着的结合亲和力，表明同源产生的自由旋转在受体的结合位点引起不利的相互作用，可能是由于存在许多构象。