- Oxidation and degradation products of papaverine. Part I: Gadamer and Schulemann's papaverinol synthesis revisited
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In 1915 Gadamer published in this journal [1] a procedure for the synthesis of papaverinol 2 from papaverine 1 in excellent yield. However, he did not investigate the formation of a violet fluorescence produced upon crystallization of papaverinol 2 from ethanol. The compound responsible for this fluorescence was isolated and identified as the yet unknown quaternary ammonium ion 4, a 6a, 12a-diazadibenzo[a,g]fluorenylium derivative. The isolation of 4 and its structure determination by spectroscopic methods are described. However, its formation mechanism is unknown.
- Hermann, Tadeusz W.,Girreser, Ulrich,Michalski, Pawel,Piotrowska, Karolina
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- Natural Product Diversification by One-Step Biocatalysis using Human P450 3A4
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Efficient synthetic techniques for the diversification of natural products are incremental for drug discovery processes of the pharmaceutical industry because these complex bioactive compounds often require an adjustment of properties. Human liver P450 3A4, key player of the body's detoxification system and decisive factor of a drug's metabolic fate, is renowned for its broad substrate scope including many natural products. In this study, we investigated the synthetic potential of human P450 3A4 for the diversification of natural product classes and isolated the produced metabolites of six selected natural products at a preparative 100-mg scale. Aided by efficient expression levels in P. pastoris, this whole-cell biocatalyst was found to be highly effective at the intended job allowing the identification of a total of 31 authentic human metabolites, many of them for the first time. By revealing an unprecedented degree of diversification, this study extends the synthetic repertoire for efficient enzymatic natural product modification in a one-step fashion and adds a completely new view to an old enzyme traditionally used for inhibition and toxicology studies.
- Fessner, Nico D.,Grimm, Christopher,Srdi?, Matic,Weber, Hansj?rg,Kroutil, Wolfgang,Schwaneberg, Ulrich,Glieder, Anton
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- Preparation method of papaverine compounds
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The invention relates to a preparation method of papaverine compounds. Specifically, the invention relates to a preparation method of a compound as shown in a formula II, and the preparation method comprises a step of reacting a compound as shown in a formula III in the presence of an oxidizing agent. The method is high in yield, mild in reaction condition and suitable for industrial production.
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Paragraph 0068-0075
(2021/07/21)
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- One-Pot Synthesis of Papaverine Hydrochloride and Identification of Impurities
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Abstract: A one-pot synthesis of papaverine hydrochloride with 99.6% purity was performed using xylene as solvent for the entire process. The critical parameters of each step, as well as the impurities generated, were identified. The overall yield was improved to 63%. The proposed synthetic procedure is suitable for industrial production.
- Qiu, Zeng-Feng,Wu, Ze-Nong,Yang, Zhe-Zhou,Yu, Wen-Shuai,Zhang, Fu-Li,Zhao, Chun-Jie
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p. 1295 - 1299
(2020/09/16)
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- A divergent approach to benzylisoquinoline-type and oxoaporphine alkaloids via regioselective direct ring metalation of alkoxy isoquinolines
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Methoxy- and benzyloxy-substituted isoquinolines are regioselectively metalated at C-1 with the Knochel-Hauser base, subsequent trapping with aromatic aldehydes gives aryl(isoquinolin-1-yl)carbinols as building blocks for divergent syntheses of different types of benzylisoquinoline alkaloids. Photochemical cyclization of ortho-bromo analogues under reductive conditions gives oxoaporphine alkaloids. Nine benzylisoquinoline alkaloids and two oxoaporphine alkaloids were obtained in two or three steps from appropriate isoquinolines.
- Melzer, Benedikt,Bracher, Franz
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p. 7664 - 7672
(2015/07/15)
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- Photostabilization of papaverine hydrochloride solutions
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The stability of aqueous and non-aqueous papaverine hydrochloride solutions exposed to the UV radiation is poor. In order to enhance its photo-stability suitable light absorbers may be used. There were four photo-protectors considered in this work: 4-aminobenzoic acid, sodium benzoate, methyl 4-hydroxybenzoate and propyl 4-hydroxybenzoate, whose UV absorption spectra characteristics match to some extent with the UV spectrum of papaverine. Approximately 20 mg/mL papaverine chloroform solutions with the above non-toxic additives in the concentrations 0.01; 0.05; 0.10% were exposed to the UV light of 254 nm. High performance capillary electrophoresis was used to determine the papaverine hydrochloride concentration loss as a function of time exposition to the light. It was found that papaverine hydrochloride photolysis proceeds according to the first-order kinetics. Methyl 4-hydroxybenzoate was found to be the best UV radiation-protective agent, and at the concentration 0.10%, the reaction rate constant decreases from 0.143 h-1 to 0.028 h -1. Both 4-hydroxybenzoate esters develop a more efficient UV radiation-protective activity than sodium benzoate, because the latter additive molar extinction coefficient is less significant. However, in spite of a high value of 4-aminobenzoic acid molar absorptivity coefficient, it is an unsuitable photo-protector for papaverine hydrochloride solutions, because its UV absorption spectrum does not match with that of papaverine.
- Piotrowska, Karolina,Hermann, Tadeusz W.,Pawelska, Alicja
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p. 321 - 326
(2011/08/07)
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- SYNTHESIS OF 2,3,8,9-TETRAMETHOXY-11-PHENYL-5,6-DIHYDRODIBENZINDOLIZINE
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2,3,8,9-Tetramethoxy-11-phenyldibenzindolizine was obtained in high yield from (6,7-dimethoxyisoquinolin-1-yl)-(3,4-dimethylphenyl)phenylcarbinol by cyclization in the presence of formic acid.The behavior of (6,7-dimethoxyisoquinolin-1-yl)-(3,4-dimethoxyphenyl)methylcarbinol and (6,7-dimethoxyisoquinolin-1-yl-(3,4-dimethoxyphenyl)carbinol was studied under these same conditions. 2,3,7,8-Tetramethoxy-11-phenyl-5,6-dihydrodibenzindolizine was obtained by hydrogenation on rhenium heptasulfide.
- Alarcon, Jorge A. R.,Soldatenkov, A. T.,Soldatova, S. A.,Samalloa, Alicia U.,Obando, Juan U.,Prostakov, N. S.
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p. 1054 - 1058
(2007/10/02)
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- Selective inhibition of calcium entry induced by benzylisoquinolines in rat smooth muscle
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The mechanism of relaxant activity of six benzylisoquinolines was examined in order to determine the minimal structural requirements that enable these compounds to have either a non-specific action like papaverine or an inhibitory activity on calcium entry via potential-operated channels. All the alkaloids tested totally or partially relaxed KCl-depolarized rat uterus and inhibited oxytocin-induced rhythmic contractions. Only glaucine and laudanosine inhibited K+-induced uterine contractions more than oxytocin-induced uterine contractions. In Ca+-free medium, sustained contractions induced by oxytocin or vanadate were relaxed by the alkaloids tested except for glaucine and laudanosine indicating no inhibitory effect on intracellular calcium release. Those alkaloids containing an unsaturated heterocyclic ring (papaverine, papaverinol, papaveraldine, N-methylpapaverine and dehydropapaverine) exhibited a more specific activity than those with a tetrahydroisoquinoline ring.
- Anselmi,Fayos,Blasco,Candenas,Cortes,D'Ocon
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p. 337 - 343
(2007/10/02)
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