- Quantitative Determination of Pt- Catalyzed d -Glucose Oxidation Products Using 2D NMR
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Quantitative correlative 1H-13C NMR has long been discussed as a potential method for quantifying the components of complex reaction mixtures. Here, we show that quantitative HMBC NMR can be applied to understand the complexity of the catalytic oxidation of glucose to glucaric acid, which is a promising bio-derived precursor to adipic acid, under aqueous aerobic conditions. It is shown through 2D NMR analysis that the product streams of this increasingly studied reaction contain lactone and dilactone derivatives of acid products, including glucaric acid, which are not observable/quantifiable using traditional chromatographic techniques. At 98% glucose conversion, total C6 lactone yield reaches 44%. Furthermore, a study of catalyst stability shows that all Pt catalysts undergo product-mediated chemical leaching. Through catalyst development studies, it is shown that sequestration of leached Pt can be achieved through use of carbon supports.
- Armstrong,Hirayama,Knight,Hutchings
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p. 325 - 335
(2019/01/04)
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- Field survey of glycyrrhiza plants in Central Asia (5). Chemical characterization of G. Bucharica Collected in Tajikistan
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One triterpene and five triterpene glycosides, including four new compounds, have been identified in the underground parts of Glycyrrhiza bucharica, which was shown to be closely related to Glycyrrhizin-producing Glycyrrhiza species, G. uralensis, G. glabra and G. inflata, based on their chloroplast rbcL sequences. Two known compounds were identified squasapogenol and macedonoside C. The structures of four new compounds, bucharosides A, B, C, and D, were determined to be 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucuronopyranosyl-(1→2)-β-D-glucuronopyranosyl-22-O-α-L-rhamnopyranosyl squasapogenol, 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucuronopyranosyl-(1→2)-β-D-glucuronopyranosyl-macedonic acid, 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucuronopyranosyl-(1→2)-β-D-glucuronopyranosyl-squasapogenol, and 22-O-α-L-rhamnopyranosyl squasapogenol, respectively. Contents of these triterpene glycosides were less than 0.5% of dry weight, and no main saponin, like glycyrrhizin or macedonoside C found in other Glycyrrhiza species, was found in the underground parts of G. bucharica.
- Hayashi, Hiroaki,Yokoshima, Keiko,Chiba, Ren,Fujii, Isao,Fattokhov, Inoyat,Saidov, Madibron
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p. 534 - 539
(2019/07/22)
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- Efficient synthesis of 1β-O-acyl glucuronides via selective acylation of allyl or benzyl d-glucuronate
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Acyl glucuronides are key metabolites for many carboxylic acid-containing drugs, notably those of the non-steroidal anti-inflammatory class. In the processes of drug safety assessment and new drug development, it is essential that acyl glucuronides, if formed in vivo, should be made conveniently available for bioevaluation. We recently showed that selective acylation of allyl glucuronate is a promising method for the synthesis of these metabolites in good yield and with excellent β-anomeric selectivity. We now give fuller details of the allyl ester method and further report that benzyl glucuronate performs at least equally well in the acylation step, offering the advantage of very mild deprotection by catalytic transfer (or conventional) hydrogenation. Depending on the compatibility of other functional groups, as discussed below, this will be the method of choice for many acyl glucuronide syntheses. The value of the method is demonstrated in particular by the synthesis of several acyl glucuronides that are known metabolites of important drugs.
- Bowkett, Elizabeth R.,Harding, John R.,Maggs, James L.,Park, B. Kevin,Perrie, Jennifer A.,Stachulski, Andrew V.
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p. 7596 - 7605
(2008/02/08)
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- Derivatives of basic polyene macrolides and their preparation
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The present invention relates to basic polyene macrolide derivatives, characterized in that they comprise a basic polyene macrolide which is N-substituted by a 1-amino-1-deoxyketose group which in turn is substituted or unsubstituted, to a process for their preparation and to their use for obtaining drugs.
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- Cosmetic composition
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A composition suitable for topical application to mammalian skin or hair for inducing, maintaining or increasing hair growth comprises a glycosaminoglycanase inhibitor chosen from aldonomonolactones, alduronomonolactones and acylated monosaccharides, and a cosmetically acceptable vehicle for the inhibitor; the total amount of the inhibitor present in the composition being sufficient to increase hair growth in the rat, when said composition is applied topically thereto over a period of no more than 3 months, by at least 10% more than that obtainable using a control composition from which the said inhibitor has been omitted, in accordance with the Rat Hair Growth Test.
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- Hair growth composition containing citric acid esters
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Triesters of citric acid are used for inducing, maintaining or increasing hair growth. Compositions for topical application to mammalian hair or scalp comprise an effective amount of from 1% to 99% by weight of an ester of citric acid having the structure (1): where, R1, R2 and R3 each independently represent a branched or unbranched alkyl, alkenyl, aryl, alkylaryl or arylalkyl group, each said group having from 1 to 18 carbon atoms, R4 represents -H, or a branched or unbranched saturated or unsaturated acyl, alkyl, aryl, alkylaryl or aylalkyl group having from 1 to 18 carbon atoms, in the presence of a cosmetically acceptable vehicle for the citric acid ester and in the absence of solid absorbent for the ester;, said effective amount of said ester being sufficient to increase hair growth in the rat, when said composition is applied topically thereto over a period of no more than three months, by at least 10% more than that obtainable using a control composition from which the said ester has been omitted, in accordance with the Rat Hair Growth Test.
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- Cosmetic composition
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A composition suitable for topical application to mammalian skin or hair comprises: (a) a growth factor chosen from: (i) transforming growth factor alpha (TGF-α), (ii) transforming growth factor beta (TGF-β), (iii) insulin-like growth factor-1 (IGF-1), (iv) fragments thereof of one or more of said growth factors, and (v) mixtures thereof of said growth factors or fragments of said growth factors; and (b) a cosmetically acceptable vehicle for the growth factor or fragments thereof; the total amount of growth factor being sufficient to increase hair growth in the rate, when the composition is applies topically thereto over a period of no more than 3 months, by at least 10% more than that obtainable using a control composition from which the said growth factor has been omitted, in accordance with the Rat Hair Growth Test.
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- Carbohydrate lactam derivatives and their use in cosmetic compositions
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A composition suitable for topical application to mammalian skin or hair for inducing, maintaining or increasing hair growth comprises: (i) a chemical inhibitor of glycosidase activity chosen from lactams having the structure: where A1 and A6 are -H, -CH3,, - , or A1 and A6 being the same or different, and at least one of which being the group:, , , in a lactam ring;, and where Q is -OT?, -NHT? or a lactam linkage to A1 or A6;, the Q groups being the same or different, and at least one of which is involved in a lactam linkage;, and where T is the same or different and is chosen from, -H, -CpH2p+1or a metal ion,T? is -H or -COCpH2p+1, and, p is an integer of from 1 to 22;, provided that:, where any of the Q groups is, -OT? or -NHT?,then that group or groups can be of either stereochemical configuration with respect to the plane of the ring; and (ii) a cosmetically acceptable vehicle for the chemical inhibitor. Certain novel lactams are also claimed.
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