- Spectrofluorimetric determination of 3-methylflavone-8-carboxylic acid, the main active metabolite of flavoxate hydrochloride in human urine
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A simple, sensitive and selective spectrofluorimetric method has been developed for the determination of 3-methylflavone-8-carboxylic acid as the main active metabolite of flavoxate hydrochloride in human urine. The proposed method was based on the measurement of the native fluorescence of the metabolite in methanol at an emission wavelength 390 nm, upon excitation at 338 nm. Moreover, the urinary excretion pattern has been calculated using the proposed method. Taking the advantage that 3-methylflavone-8-carboxylic acid is also the alkaline degradate, the proposed method was applied to in vitro determination of flavoxate hydrochloride in tablets dosage form via the measurement of its corresponding degradate. The method was validated in accordance with the ICH requirements and statistically compared to the official method with no significant difference in performance.
- Zaazaa, Hala E.,Mohamed, Afaf O.,Hawwam, Maha A.,Abdelkawy, Mohamed
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- Preparation method for synthesizing flavoxate hydrochloride intermediate (3-methylflavone-8-carboxylic acid)
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The invention provides a preparation method for synthesizing a flavoxate hydrochloride intermediate (3-methyl flavone-8-carboxylic acid). The preparation method comprises the following steps: preparing 2-benzoyloxy-3-methyl propionyl benzoate, and preparing 3-methyl flavone-8-carboxylic acid. The method has the advantages of high product yield, high purity, short technological process, low production risk and low production cost.
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Paragraph 0023; 0026-0027; 0030; 0033-0034; 0037; 0040-0041
(2020/06/05)
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- Halo-containing 3-methylflavone-8-carboxylic acid derivatives
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This invention relates to derivatives of 3-methylflavone-8-carboxylic acid represented by the formula (1) STR1 wherein R represents a hydrogen atom, a lower alkyl group or a group STR2 (wherein R1 and R2 represent a lower alkyl group or R1 and R2, when taken together with the nitrogen atom to which they are attached, may form a heterocyclic ring with or without an intervening hetero atom, and n is an integer of 1 to 4), and X represents a halogen atom, which are useful as intermediates. This invention also relates to processes for preparing the same.
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- Electrochemical Epoxidation and Carbon-Carbon Bond Cleavage for the Preparation of 3-Methyl-4-oxo-2-phenyl-4H-1-benzopyran-8-carboxylic Acid from 3-Methyl-2-phenyl-8-(1-propenyl)-4H-1-benzopyran-4-one
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Electrooxidative carbon-carbon bond cleavage is useful for the preparation of 3-methyl-4-oxo-2-phenyl-4H-1-benzopyran-8-carboxylic acid (1b) from 3-methyl-2-phenyl-8-(1-propenyl)-4H-benzopyran-4-one (2).Olefin 2 was transformed into 3-methyl-8-(1,2-epoxypropyl)-3-methyl-2-phenyl-4H-1-benzopyran-4-one (3) by the electrochemical bromohydrination in an MeCN-H2O-H2SO4-NaBr-(Pt) system followed by treatment of aqueous sodium hydroxide (94percent).The epoxide 3 was electrooxidized in an MeOH-H2SO4-(C) system, affording 8-formyl-3-methyl-2-phenyl-4H-1-benzopyran-4-one (4) in 83percent yield.Hydrogen peroxide oxidation of 4 in refluxing 2-butanone gave 1b in 86percent yield.
- Uneyama, Kenji,Masatsugu, Yosinori,Torii, Sigeru
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p. 2361 - 2365
(2007/10/02)
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