Uridine 5 -nitro

The studies of Levene and LaForge60 on the nitration of uridine have since been re-investigated. It had been reported, several decades ago, that treatment of uridine with nitric acid produced a Nitro-Uridin-Carbon-saure which was stated to be a dimer containing an anhydro typeof linkage (positions unspecified) between two nucleoside residues.60 According to an abstract,269 this compound has now been identified as the monomeric 5-ni-tro-l-(/8-D-ribosyluronic acid)uracil (CXXII) this was converted to the isopropyl ester and the 2,3-O-isopropylidene acetal thereof. Nitration of the pyrimidine moiety of uridine without oxidation of the 4-(hydroxy-... 

Another method of seemingly general applicability to carbohydrates was used by Coat et al. to conjugate uridine to proteins. The isopropyli-dine derivative was allowed to react withp-nitrobenzoyl chloride to yield the 5 ester. Removal of the isopropylidine protecting group and hydrogenation of the nitro group made it possible to link the uridine derivative to the protein by a diazotization reaction. 

This leaves positions (3 ), (4 ), and (S ) as possible points for the union. However, position (S ) is excluded because bromine reacts with uridine to give S -bromo-uridine, and nitric acid gives a 6 -nitro derivative which, on hydrolysis, yields S -nitro-uracil. Position (4 ) is excluded because treatment of bromo-uridine with phenylhydrazine gives 4 -S -diphenylhydrazino-uridine. Hence in both uridine and cytidine the ribose residue is situated at position (3 ) of the base. This conclusion has been verified by indirect methods. ... 

Nucleosides, Nucleotides, Derivatives, and Related Compounds. — 5-Dimethyl-aminouridine, 5-methylaminomethyl-2-thiouridine, 2, 3 -O-isopropylidene-5-methylaminomethyl-2-thiouridine, 2 -deoxy-5-isopropyluridine, 5-amino-2, 5 -dideoxy-5-iodouridine, 5-nitro-l-( 3-D-ribofuranosyluronic acid)uracil, uridine 3 -phosphate, and uridine 5-diphosphate dipotassium salt. ... 

It has clearly been shown that inhibition of poly(ADP-ribose) synthetase was responsible for the cytotoxicity exhibited by five of the six benzamides tested. 3-Nitrobenz-amide was markedly more cytotoxic than would be expected on the basis of its K,. Nitro-compounds have been shown to be cytotoxic and genotoxic. This is thought to arise by reduction to reactive intermediates which can then modify DNA [3]. When uridine incorporation was correlated with the Hammet constant, 3-nitrobenzamide fitted very well. The shorter exposure time in this assay minimises any metabolite effects. 

Aminouridine, 5-vinyl-2 -deoxyuridine, 5-ethynyl-2 -deoxyuridine, 5-nitro-l-05-D-riburonosyl)uracil, uridine 5 -methylphosphate. ... 

Nitromethane condensation with the dialdehyde obtained from periodate-oxidized uridine yields a crystalline 3-deoxy-3-nitro-g-D-glucopyranosyluracil contaminated by the D-galacto isomer their... 

The D-ribofuranosyl hydrazine (9) can be used to produce pyrazole nucleosides such as (10) (Scheme 1) with -selectivity, and similar 2 -deoxy-compounds were also made. Ribofuranosylamine (11) (Scheme 1) can be used as a precursor of 5-substituted uridines of type (12), which can be converted to 5-carboxamidouridine (13). 3 l-p-D-Ribofuranosyl-6-nitro-indole has been made by the indole-indoline method,... 

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