RECENT IMPROVEMENTS TOWARDS THE SYNTHESIS OF THE C-GLUCURONOSYL CANCER CHEMOPREVENTIVE (β-d-GLUCOPYRANOSYLURONATE)-4-RETINAMIDOPHENYLMETHANE

Wong, Man Fai; Weiss, Kevin L.; Curley, Robert W.

doi:10.1080/07328309608005690

Cited by 13 publications

(2 citation statements)

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“…[6] We prepared 4 and confirmed it is more potent and less toxic than 3 as a mammary tumor chemopreventive/therapeutic. [7–9] Since 4 is a substrate for β-glucuronidase and other hydrolytic processes, we prepared a number of unhydrolyzable, carbon-linked analogs [10,11] of this oxygen-linked 4 and found that, in particular, the 4-HPR- C -glucuronide ( 5 ) showed even better activity in a carcinogen-induced rat mammary tumor model. [12] This strongly suggested that these glucuronide metabolites were active as intact conjugates.…”

Section: Introductionmentioning

confidence: 99%

Improved synthesis of the C-glucuronide/glycoside of 4-hydroxybenzylretinone (4-HBR)

Cavanaugh

Narayanasamy

Walker

et al. 2016

Journal of Carbohydrate Chemistry

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Improvements in the synthesis of carbon-linked glucuronide/glucoside conjugates of cancer chemopreventive retinoids have been achieved starting with 2,3,4,6-tetra-O-benzyl-D-glucopyranose. The revised approach demonstrates better yields, eliminates the use of an expensive, carcinogenic protecting group reagent, and avoids much painstaking chromatography. The new approach should allow synthesis of larger quantities of the agents for detailed animal and mechanistic studies.

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Section: Introductionmentioning

confidence: 99%

Improved synthesis of the C-glucuronide/glycoside of 4-hydroxybenzylretinone (4-HBR)

Cavanaugh

Narayanasamy

Walker

et al. 2016

Journal of Carbohydrate Chemistry

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“…In the course of synthesizing 1, selective PtO 2mediated oxidation (6,7) of the 6-hydroxymethyl group of glucosylbenzene (4) followed by esterification and acetylation produced a product 5 that showed unusual complexity in the 1 H NMR spectrum in the region of the pyran ring protons. This was true for all resonances except that assigned for the H-1 proton.…”

Section: Introductionmentioning

confidence: 99%

Virtual coupling of pyran protons in the 1H NMR spectra of C- and N-glucoronides: Dependence on substitution and solvent

2001

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We have observed that certain C- and N-glucuronides prepared as intermediates for breast cancer preventives demonstrate non-first order 1H NMR spectra that are not the result of impurities or degradation but are instead due to virtual coupling in the pyran proton network. This virtual coupling shows the expected dependence on solvent and field strength and, more importantly, on the nature of the C-1 substitution. Although the hybridization of the atom bonded to C-1 may play a role, it appears that steric and/or electronic factors, which have the effect of increasing Delta(v)/J for H-3 and H-4, are critical for eliminating the spectral complexity. These observations, which appear to be fairly general, suggest that this phenomenon should be considered when addressing the purity of pharmaceutical agents containing these types of structural units.

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Oxoammonium‐ and Nitroxide‐Catalyzed Oxidations of Alcohols

2009

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The discovery in 1959 of stable nitroxide‐based free radicals such as the prototypical 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) led to their use as electron spin resonance (ESR) spin labels in chemistry, biomedicine, and materials science. These nitroxides are prepared by the oxidation of secondary amines that contain no hydrogen atoms on the alpha‐carbons. The unique redox properties of nitroxides enable their use as oxidants in organic synthesis. The varied preparation and uses of oxoammonium salts as stoichiometric oxidants for alcohols are one subject of this review. Oxoammonium ions as oxidants for alcohols have a number of advantages, for example, the method is heavy‐metal free and some of the reactions can be performed in water or aqueous mixtures. A few side reactions are associated with these oxidations. The most serious is the fast reaction of the oxoammonium ion with free amines The several ways these oxidation reactions can be carried out are discussed in detail. They are: Oxidations using stoichimetric quantities of preformed oxoammonium salts carried out in either acidic, neutral, or basic conditions; reactions in which stoichiometric quantities of oxoammonium salts are generated in situ by disproportionation of a nitroxide in the presence of a strong acid; nitroxide‐catalyzed oxidations using a secondary oxidant; efficient nitroxide‐catalyzed oxidations of primary alcohols to carboxylic acids; and oxidations of primary alcohols or hemiacetals that can lead to lactones.

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RECENT IMPROVEMENTS TOWARDS THE SYNTHESIS OF THE C-GLUCURONOSYL CANCER CHEMOPREVENTIVE (β-d-GLUCOPYRANOSYLURONATE)-4-RETINAMIDOPHENYLMETHANE

Cited by 13 publications

References 10 publications

Improved synthesis of the C-glucuronide/glycoside of 4-hydroxybenzylretinone (4-HBR)

Improved synthesis of the C-glucuronide/glycoside of 4-hydroxybenzylretinone (4-HBR)

Virtual coupling of pyran protons in the 1H NMR spectra of C- and N-glucoronides: Dependence on substitution and solvent

Oxoammonium‐ and Nitroxide‐Catalyzed Oxidations of Alcohols

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