Several 5-fluorouracil derivatives in which the phthalidyl (1, 3-dihydro-3-oxoisobenzofuran-1-yl) group, appropriately substituted on its benzene ring, is substituted at the N (1)-or N (3)-position or at both positions were synthesized, and their antitumor activities were evaluated. Among these compounds, 1-(1, 3-dihydro-3-oxoisobenzofuran-1-yl)-5-fluorouracil (3a, 590-S) was shown to be markedly active against several experimental tumor systems. Several methods for a simple and efficient large-scale preparation of 3a were examined. The large-scale preparation of 3a was effected most efficiently by the condensation of 5-fluorouracil with the quaternary ammonium salt of 3-bromophthalide in the presence of a base. The synthesis of (+)- and (-)-3a is also described.
Application of the Benzyloxycarbonyloxymethyl Moiety to a Protective Group of 5-Fluorouracil. Selective Alkylation of Amide Nitrogen of the Uracil Ring
Selective alkylation of 5-fluorouracil using the benzyloxycarbonyloxymethyl moiety as a protectivegroup of amide nitrogen of the uracil ring is described. Protection, alkylation and deprotection were carried out in high yields.
Benzhydryl as an Efficient Selective Nitrogen Protecting Group for Uracils
作者:Fan Wu、Musole G. Buhendwa、Donald F. Weaver
DOI:10.1021/jo0485076
日期:2004.12.1
Regioselective N-substitution of the less active nitrogen within uracil analogues has been achieved following preliminary N-protection at the more active N-position with a benzhydryl protecting group. This protecting group is stable to concentrated HCl (aqueous) at reflux temperature, TFA at room temperature, and Pd-C-catalyzed normal pressure hydrogenation at room temperature; the benzhydryl group can be removed quantitatively and selectively with a 10% triflic acid solution in TFA at 0 degreesC.