Synthesis of pyrimidin-2-one nucleosides as acid-stable inhibitors of cytidine deaminase
One of the problems encountered in the use of tetrahydrouridine (THU, 2) and saturated 2-oxo-1,3-diazepine nucleosides as orally administered cytidine deaminase (CDA) inhibitors is their acid instability. Under acid conditions these compounds are rapidly converted into inactive ribopyranoside forms....
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Published in | Journal of medicinal chemistry Vol. 29; no. 8; pp. 1374 - 1380 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Washington, DC
American Chemical Society
01.08.1986
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Subjects | |
Online Access | Get full text |
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Summary: | One of the problems encountered in the use of tetrahydrouridine (THU, 2) and saturated 2-oxo-1,3-diazepine nucleosides as orally administered cytidine deaminase (CDA) inhibitors is their acid instability. Under acid conditions these compounds are rapidly converted into inactive ribopyranoside forms. A solution this problem was sought by functionalizing the acid-stable but less potent CDA inhibitor 1-beta-D-ribofuranosyl-2(1H)-pyrimidinone (1) with the hope of increasing its potency to the level achieved with THU. The selection of the hydroxymethyl substituent at C-4, which led to the synthesis of 4-(hydroxymethyl)-1-beta-D-ribofuranosyl-2(1H)-pyrimidinone (10), 3,4-dihydro-4-(hydroxymethyl)-1-beta-D-ribofuranosyl-2(1H)-pyrimidinone (7), and 3,4,5,6-tetrahydro-4-(dihydroxymethyl)-1-beta-D-ribofuranosyl-2(1H)-p yrimidinone (28) was based on the transition-state (TS) concept. The key intermediate precursor, 4-[(benzoyloxy)methyl]-1-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)-2(H) -pyrimidinone (24), was obtained via the classical Hilbert-Johnson reaction between 2-methoxy-4-[(benzoyloxy)methyl]pyrimidine (20) and 2,3,5-tri-O-benzoyl-1-D-ribofuranosyl bromide (21). Deprotection of 24 afforded compound 10, while its sodium borohydride reduction products afforded compounds 7 and 28 after removal of the blocking groups. Syntheses of 3,4-dihydro-1-beta-D-ribofuranosyl-2(1H)-pyrimidinone (9) and 3,6-dihydro-1-beta-D-ribofuranosyl-2(1H)-pyrimidinone (8), which lack the hydroxymethyl substituent, was accomplished in a similar fashion. The new compounds bearing the hydroxymethyl substituent were more acid stable than THU, and their CDA inhibitory potency, expressed in terms of Ki values, spanned from 10(-4) to 10(-7) M in a manner consistent with the TS theory. Compound 7, in particular, was superior to its parent 1 and equipotent to THU (Ki = 4 X 10(-7) M) when examined against mouse kidney CDA. The superior acid stability of this compound coupled to its potent inhibitory properties against CDA should provide a means of testing oral combinations of rapidly deaminated drugs, viz. ara-C, without the complications associated with the acid instability of THU. |
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Bibliography: | istex:0F2DBCE3063DF0C5DF88C143ADE2BEB0FE19250B ark:/67375/TPS-2V5QMTFG-S ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-2623 1520-4804 |
DOI: | 10.1021/jm00158a009 |