2-(b -D-Ribofuranosyl)-4-(3-nitrophenylazo)-5-trifluoromethyl-2,4-dihydro-pyrazol-3-one
Hussein F. Zohdi* and Abdelfattah Haikal
Department of Chemistry, Faculty of Science, United Arab Emirates University,
P.O.Box 17551 Al-Ain, UAE
E-mail: [email protected]
and [email protected]
Received: 5 June 2001 / Accepted: 15 December 2001 / Published: 20 December 2001
The desired compound 2 was obtained by complete deprotection of the acetylated nucleoside 1 [1] using triethylamine [2]. To a solution of 1 (0.9g, 1.4 mmol) in methanol (25 ml) was added triethylamine (2 ml). The mixture was stirred at room temperature and the reaction was followed by tlc. After complete deprotection (24 hours), the reaction mixture was evaporated and coevaporated with methanol (3 x 30 ml), then chromatographed over silica gel using CH2Cl2/MeOH (92:8 v/v) to give 0.56g (90%) of 2 as yellow powder.
Rf (CH2Cl2/MeOH, 94/6 v/v): 0.2.
UV (lmax , 95% ethanol): 255, 415.
MS (m/z): 433.
1H-NMR (250 MHz, DMSO-d6): 3.39-3.54(m, 2H, H-5`, H-5``); 3.82-3.87(m, 1H, H-4`); 4.07(t, 1H, H-3`); 4.36(t, 1H, H-2`); 5.63(d, 1H, H-1`, J1`,2`=4.95); 7.74-8.55(m, 4H, aromatic CH).
13C-NMR (75 MHz, DMSO-d6): 61.92(C-5`), 70.35(C-3`); 71.83(C-2`); 84.80(C-4`); 86.10(C-1`); 111.95, 117.51, 120.66, 121.12, 123.90, 131.04(6 aromatic carbons); 136.63(q, CF3); 142.71(C-4); 148.54(C-5); 156.06(C-3).
References
1. Haikal, A.; Zohdi, H.F.; El-Neyadi, S. Molecules 2001,
6, M262.
2. Spohr, U.; Lemieux, R. Carbohydr. Res. 1988, 174,
211.
Sample Availability: Available from the authors and from MDPI.
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