110567-23-2Relevant articles and documents
Synthesis of [13C4]Baraclude (entecavir)
Tran, Scott B.,Ekhato, Ihoezo V.,Rinehart, J. Kent
scheme or table, p. 485 - 489 (2010/07/04)
Entecavir, labeled as 1H-[13C4]purin-6(9H)-one, was prepared from commercially available [13C]guanidine HCl, 1 and diethyl [1,2,3-13C3]malonate, 2. The reagents were condensed together to give 2-amino-4,6-dichloro[2,4,5,6-13C 4]pyrimidine 3, which in turn was coupled to an optically active amino cyclopentanol derivative, 9. A further sequence of eight reaction steps completed the constructions of the purine ring system and the exocyclic olefin attachment on the cyclic pentyl portion, 18. The removal of the methoxide and benzyl protecting groups gave [13C4]entecavir, 20 in an overall yield of 6.8%. The chemical purity of the title compound was determined by HPLC to be 99.23%. The percent isotopic [13C4] abundance was found by mass spectral analysis to be 96.7%. No detectable level of the unlabeled entecavir was found by LC-MS analysis. Copyright
Synthesis of [14C]-radiolabelled entecavir
Ogan, Marc D.,Kucera, David J.,Pendri, Yadagiri R.,Rinehart, J. Kent
, p. 645 - 655 (2007/10/03)
Radiolabelled [l4C]entecavir, (1), was prepared in 12 steps from (1S,2R,3S,5R)-3-(benzyloxy)-2-(benzyloxymethyl)-6-oxa-bicyclo[3.1.0]hexane 2. The chemical yield of [l4C]entecavir was 14% from the epoxide 2. Introduction of [14
Use of Diethylaminosulphur Trifluoride (DAST) in the Preparation of Synthons of Carbocyclic Nucleosides
Biggadike, Keith,Borthwick, Alan D.,Evans, Derek,Exall, Anne M.,Kirk, Barrie E.,et al.
, p. 549 - 554 (2007/10/02)
Diethylaminosulphur trifluoride (DAST) converted the protected amino triol (4) into the fluorine-containing compounds (8) and (10).The same reagent converted the alcohol (9) into compounds (10), (5), and (11) and transformed the azido alcohol (15) into the fluoroazides (16) and (19).The fluorinated compounds (5), (8), and (16) are useful synthons for fluorocarbocyclic nucleosides.The effect of neighbouring groups on the course of some DAST reactions is discussed.