An alternative method suitable for a large scale synthesis of 4'-ethynyl-2',3'-didehydro-3'-deoxythymidine
Author(s) -
Kazuhiro Haraguchi
Publication year - 2004
Publication title -
nucleic acids symposium series
Language(s) - English
Resource type - Journals
eISSN - 1746-8272
pISSN - 0261-3166
DOI - 10.1093/nass/48.1.43
Subject(s) - yield (engineering) , derivative (finance) , chemistry , diastereomer , nucleoside , thymine , medicinal chemistry , triple bond , stereochemistry , organic chemistry , double bond , dna , materials science , biochemistry , economics , financial economics , metallurgy
Reaction of 4', 5'-unsaturated thymine nucleoside 1 with Pb(OBz)4 gave the 4'-benzoyloxy derivative 9 as a diastereomeric mixture in 79% yield. When 9 was treated with Me3Al in CH2Cl2 at 0 degrees C, spiro-derivative 10 was formed as the major product in 76% yield. On the other hand, the use of Me2AlCl led to the formation of the 4'-chlorinated product 11, which was subjected to in situ treatment with Me3Al to give the 4'-alpha-methyl derivative 12 (15%) as well as the 4'-beta-methyl counterpart 13 (38%). Formation of 11 was also observed during the reaction between 9 and EtAl(Cl)C[triple bond]CTMS, prepared from EtAlCl2 and LiC[triple bond]CTMS. From this reaction, the 4'-ethynyl nucleoside 14 was obtained stereoselectively in 56% yield.
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