摘要:
O-6-(4-Nitrophenyl)inosine (1a), O-6-(4-nitrophenyl)guanosine (1c) and O-6-(4-methylumbelliferonyl)inosine (2) were obtained by reaction of 6-chloro-9-(beta-D-ribofuranosyl)purine (3a) or 2-amino-6-chloro-9-(beta-D-ribofuranosyl)purine (3c) with sodium salts of 4-nitrophenol or 4-methylumbelliferone in N,N-dimethylformamide. Similarly, 6-chloro-9-(beta-D-2,3-isopropylideneribofuranosyl)purine (3b) was transformed to 2',3'-O-isopropylidene-O-6-(4-nitrophenyl)inosine (1b). Deprotection of 1b with CF3COOH gave compound 1a and O-6-(4-nitrophenyl)hypoxanthine (4). Compounds la and Ic are substrates for adenosine deaminase releasing 4-nitrophenol which is readily detected visually or spectrophotometrically. Rate and extent of hydrolysis of 1a are significantly increased in the presence of purine nucleoside phosphorylase but xanthine oxidase has no influence. A potential fluorogenic analogue 2 is not a substrate for adenosine deaminase.