B. C. Pal, C. Ghosh, S. K. Sethi
1988
Citations
0
Influential Citations
3
Citations
Journal
Nucleosides, Nucleotides & Nucleic Acids
Abstract
Abstract 5-Bromo-(1) and 5-iodo-2′-deoxycytidine (2) undergo 100 percent dehalogenation to 2′-deoxycytidine on heating with cysteine in IN aq K2CO3 in a nitrogen atmosphere at 50° for 72 h and 21 h, respectively. 5-Chloro-2′-deoxycytidine (3) and 1-methyl-5-chlorocytosine (3m) on the other hand undergo very little dehalogenation, forming instead two products, 4, 5 and 4m, 5m respectively, whose structures have been determined by mass spectrometry and proton magnetic resonance spectroscopy of the 3m products: 1-methyl-5-(cystein-S-yl)cytosine (4m) and 3-methyl-2,6,7,8 -tatrahydro-2-oxo-3H-pyrimido [5,4-b][1,4]-thiazine-7-carboxylic acid (5m), mp. 236°C, 78 percent yield. Initially produced 4m undergoes a novel and facile cyclization to form 5m with loss of NH3 in the presence of cysteine. The compound 3m, mp. 258°C, has been synthesized by treating 1-methylcytosine with N-chlorosuccinimide in acetic acid at 105° for 3 h in 56 percent yield. Ultraviolet absorption spectral properties of 1, 2, 3, 3m, 4, 4m, ...