13C and 15N NMR chemical shift assignments of N-1-(2- azidoethyl)-4-R-pyrimidin-2-ones by 1H,X HMQ(B)C with z-gradient selection

✍ Scribed by Erkki Kolehmainen; Kari Lappalainen; David Šaman; Antonin Holý; Jaroslav Günter

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 181 KB
• Volume: 36
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199806)36:6<442::aid-omr314>3.0.co;2-g

✦ Synopsis

13C and 15N NMR chemical shift assignments based on z-gradient selected 1H,X (X \ 13C and 15N) HMQC and HMBC experiments are reported for N-1-(2-azidoethyl)pyrimidin-2-one (ring system of cytosine), its Ðve 4-R derivatives [where and and 2-azidoethyl tosy

) 2 ] late. The possibilities of detecting all nitrogens in these molecules containing (i) an azido group at N-1 and (ii) an electronegative substituent at C-4 are limited. First, the terminal nitrogen of the azido group is difficult to observe because the nearest proton (in a group) is located four bonds away from it. Second, in contrast to N-1, N-3 in CH 2 N-1-(2-azido-ethyl)-4-pyrimidin-2-ones remained undetected. For that reason, an unsubstituted derivative (R \ H) was also prepared, where N-3 was easily observed.