- Lipase-Catalyzed Production of (S)-Carprofen Enhanced by Hydroxyethyl-β-cyclodextrins: Experiment and Optimization
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Stereoselective resolution of (R,S)-carprofen methyl ester (CPOMe) by lipase-catalyzed hydrolysis to (S)-carprofen (CP) was investigated in an aqueous medium. With the highest catalytic activity, Candida antarctica Lipase A (CALA) was selected as catalyst compared with eight other lipases. Hydroxyethyl-β-cyclodextrin (HE-β-CD) was added to enhance the solubility of (R,S)-CPOMe, which significantly raised the conversion of substrate from 11.12% to 30.84%. Response surface methodology (RSM) was adopted to evaluate the influence of factors on the substrate conversion (c) and enantiomeric excess of product (eep), such as pH, concentrations of enzyme and HE-β-CD, temperature, substrate loading, and reaction time. The optimal conditions were obtained, including pH 6.0, 40 mg/mL CALA, 0.05 mmol substrate, 35 mmol/L HE-β-CD, agitation speed of 600 rpm, temperature of 76 °C, and reaction time of 30 h. Under the above conditions, (S)-CP as the desired product was obtained with an enantiomeric excess of 96.24% and overall conversion of 46.07%.
- Yuan, Xin,Liu, Guangyong,Zhang, Panliang,Xu, Weifeng,Tang, Kewen
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Read Online
- Reshaping the active pocket of esterase Est816 for resolution of economically important racemates
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Bacterial esterases are potential biocatalysts for the production of optically pure compounds. However, the substrate promiscuity and chiral selectivity of esterases usually have a negative correlation, which limits their commercial value. Herein, an efficient and versatile esterase (Est816) was identified as a promising catalyst for the hydrolysis of a wide range of economically important substrates with low enantioselectivity. We rationally designed several variants with up to 11-fold increased catalytic efficiency towards ethyl 2-arylpropionates, mostly retaining the initial substrate scope and enantioselectivity. These variants provided a dramatic increase in efficiency for biocatalytic applications. Based on the best variant Est816-M1, several variants with higher or inverted enantioselectivity were designed through careful analysis of the structural information and molecular docking. Two stereoselectively complementary mutants, Est816-M3 and Est816-M4, successfully overcame and even reversed the low enantioselectivity, and several 2-arylpropionic acid derivatives with highEvalues were obtained. Our results offer potential industrial biocatalysts for the preparation of structurally diverse chiral carboxylic acids and further lay the foundation for improving the catalytic efficiency and enantioselectivity of esterases.
- Liu, Xiaolong,Zhao, Meng,Fan, Xinjiong,Fu, Yao
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p. 6126 - 6133
(2021/09/28)
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- Electrochemical Synthesis of Carbazoles by Dehydrogenative Coupling Reaction
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A constant current protocol, employing undivided cells, a remarkably low supporting electrolyte concentration, inexpensive electrode materials, and a straightforward precursor synthesis enabling a novel access to N-protected carbazoles by anodic N,C bond formation using directly generated amidyl radicals is reported. Scalability of the reaction is demonstrated and an easy deblocking of the benzoyl protecting group is presented.
- Kehl, Anton,Schupp, Niclas,Breising, Valentina M.,Schollmeyer, Dieter,Waldvogel, Siegfried R.
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p. 15847 - 15851
(2020/11/02)
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- Carprofen and its intermediate synthesis method
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A synthesis of carprofen, (1) 2 - (3 - bromo - 4 - chlorophenyl) propionic acid and P-nitro aniline reaction, formula C - 1 as shown in the; (2) Type C - 1 as shown in the compound is subjected to reduction reaction, formula C - 2 as shown in the; (3) Type C - 2 shown compound is subjected to diazotization reaction, preparation formula B - 3 as shown in the and by-product B - 31 shown compound mixture; (4) Type B - 3 and the product of a compound represented by B - 31 shown compound mixture through processing formula B - 3 illustrated compound; (5) Type B - 3 as shown in the reaction shown in formula A carprofen;
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- Total synthesis of carbazole alkaloids
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A Suzuki-Miyaura cross coupling, followed by triphenylphosphine mediated Cadogan reductive cyclization sequence provided efficient access to a series of carbazole alkaloids. In the present work, this approach was applied to the total synthesis of mukonine, clauszoline K, koenoline, murrayanine, murrayafoline A, mukoeic acid, glycoborine, glycozolicine, mukolidine, mukoline, glycozoline, 3-methoxy-9H-carbazole-1-carboxylic acid methyl ester, (3-methoxy-9H-carbazol-1-yl)-methanol, 3-methoxy-9H-carbazole-1-carbaldehyde, 3-methoxy-9H-carbazole-1-carboxylic acid, 2-methyl-9H-carbazole and nonsteroidal anti-inflammatory drug (NSAID) carprofen and its derivatives.
- Bhatthula, Bharath kumar goud,Kanchani, Janardhan reddy,Arava, Veera reddy,Subha
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p. 874 - 887
(2019/01/11)
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- Carprofen and its intermediate synthesis method
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A synthesis of carprofen: (1) 4 - chloroaniline and 2 - iodo - 4 - bromo-chlorobenzene reaction, generating M - 1 illustrated compound. (2) Type M - 1 as shown in the after reaction, generating M - 2 shown compound. (3) Type M - 2 by the reaction of a compound of, formula M - 3 illustrated compound. (4) Type M - 3 through the reaction of a compound represented by formula M - 4 illustrated compound. (5) The formula M - 4 through the reaction of a compound represented by formula M - 5 illustrated compound. (6) Type M - 5 as shown in the reaction shown in formula A carprofen. .
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- Carprofen and its intermediate synthesis method
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A synthesis of carprofen, comprising the following steps: (1) 2 - (3 - chloro - 4 - nitrophenyl) propionic acid and to P-chloroaniline reaction, formula A - 1 as shown in the; (2) Type A - 1 shown compound is subjected to reduction reaction, formula A - 2 illustrated compound; (3) Type A - 2 shown through the diazo coupling reaction compound, a compound represented by formula A preparation, and by-product A - 3 illustrated compound; (4) Steps (3) to obtain the compound of formula A shown and by-product A - 3 shown compound mixture through purification treatment, to obtain not comprising by-product A - 3 of formula A shown carprofen.
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- Carprofen and its intermediate synthesis method
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A synthesis of carprofen: (1) 4 - [...] and 2 - chloro - 5 - bromophenyl reaction, generating M - 1 illustrated compound. (2) Type M - 1 as shown in the after reaction, generating M - 2 shown compound. (3) Type M - 2 by the reaction of a compound of, formula M - 3 illustrated compound. (4) Type M - 3 through the reaction of a compound represented by formula M - 4 illustrated compound. (5) The formula M - 4 through the reaction of a compound represented by formula M - 5 illustrated compound. (6) Type M - 5 as shown in the reaction shown in formula A carprofen. .
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Paragraph 0025; 0052; 0053; 0054; 0055; 0056; 0057
(2019/05/22)
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- Diquats with Robust Chirality: Facile Resolution, Synthesis of Chiral Dyes, and Application as Selectors in Chiral Analysis
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Diquats with extremely high racemization barriers with ΔG≠theor of 233 kJ mol?1 at 180 °C are described. Reported configurational robustness is due to a combination of two structural features: the rigid o-xylylene tether connecting the nitrogen atoms and the presence of two substituents in the bay region of the bipyridinium scaffold. The straightforward synthesis of diquats, plus facile resolution and derivatization make them attractive for chiral application studies. This is demonstrated by: 1) synthesis of the first non-racemic diquat dyes with pronounced chiroptical properties, and 2) capability of diquats to interact stereospecifically with chiral molecules. This suggests potential for diquat derivatives to be used as chiral selectors in separation methods.
- Talele, Harish R.,Koval, Du?an,Severa, Luká?,Reyes-Gutiérrez, Paul E.,Císa?ová, Ivana,Sázelová, Petra,?aman, David,Bednárová, Lucie,Ka?i?ka, Václav,Teply, Filip
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supporting information
p. 7601 - 7604
(2018/06/11)
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- Carbazole compound, and synthesis method and application of compound
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The invention discloses a carbazole compound represented by a formula (2) and a synthesis method of the compound. A high-iodine salt is taken as a reaction raw material, and under the action of an inorganic nitrogen reagent, an additive, a base and a metal catalyst, a reaction is carried out in a solvent under a condition of 80-150 DEG C to obtain various carbazole compounds. According to the method provided by the invention, nitrogen atoms are introduced in a later period, so that the non-compatibility of nitrogen heterocyclic rings to the reaction conditions such as the metal catalyst and the like in an early reaction period is avoided. In addition, two aryl groups in the high-iodine salt are fully utilized, so that the atomic economic efficiency of the method provided by the present invention is fully exhibited. The carbazole compound prepared by the method provided by the invention can be further applied to the synthesis of non-steroidal anti-inflammatory drug carprofen.
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Paragraph 0101; 0103
(2018/06/15)
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- Nitrogen-Iodine Exchange of Diaryliodonium Salts: Access to Acridine and Carbazole
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A nitrogen-iodine exchange protocol of diaryliodonium salts with sodium azide salt is developed for general construction of significant functional acridines and carbazoles, in which introduction of nitrogen at a late stage was successfully established avoiding heteroatom incompatibility. Inorganic sodium azide served as the sole nitrogen atom source in this transformation. The diversiform functional acridines and carbazoles were comprehensively achieved through annulated diaryliodonium salts, respectively. Notably, Acridine orange (a fluorescent indicator for cell lysosomal dye) and Carprofen (a nonsteroidal anti-inflammatory drug) were efficiently established through this protocol.
- Wang, Ming,Fan, Qiaoling,Jiang, Xuefeng
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p. 216 - 219
(2018/01/17)
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- Enantioselective potential of polysaccharide-based chiral stationary phases in supercritical fluid chromatography
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The enantioselective potential of two polysaccharide-based chiral stationary phases for analysis of chiral structurally diverse biologically active compounds was evaluated in supercritical fluid chromatography using a set of 52 analytes. The chiral selectors immobilized on 2.5?μm silica particles were tris-(3,5-dimethylphenylcarmabate) derivatives of cellulose or amylose. The influence of the polysaccharide backbone, different organic modifiers, and different mobile phase additives on retention and enantioseparation was monitored. Conditions for fast baseline enantioseparation were found for the majority of the compounds. The success rate of baseline and partial enantioseparation with cellulose-based chiral stationary phase was 51.9% and 15.4%, respectively. Using amylose-based chiral stationary phase we obtained 76.9% of baseline enantioseparations and 9.6% of partial enantioseparations of the tested compounds. The best results on cellulose-based chiral stationary phase were achieved particularly with propane-2-ol and a mixture of isopropylamine and trifluoroacetic acid as organic modifier and additive to CO2, respectively. Methanol and basic additive isopropylamine were preferred on amylose-based chiral stationary phase. The complementary enantioselectivity of the cellulose- and amylose-based chiral stationary phases allows separation of the majority of the tested structurally different compounds. Separation systems were found to be directly applicable for analyses of biologically active compounds of interest.
- Kucerova, Gabriela,Kalikova, Kveta,Tesarova, Eva
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supporting information
p. 239 - 246
(2017/05/29)
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- Selective aryne formation via Grob fragmentation from the [2+2] cycloadducts of 3-triflyloxyarynes
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A chemoselective ring-opening protocol of the formal [2+2] cycloadducts of 3-triflyloxyarynes was developed to generate 2,3-aryne intermediate via Grob fragmentation. A variety of 1,3-di- and 1, 2, 3-trisubstituted arenes could be readily accessed through this [2+2] cycloaddition-2,3-aryne formation sequence. The regioselectivity in these transformations originates from the steric repulsion of the aliphatic chain.
- Shi, Jiarong,Xu, Hai,Qiu, Dachuan,He, Jia,Li, Yang
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p. 623 - 626
(2017/05/15)
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- Synthetic Processes of Carprofen
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Methods and intermediates for the synthesis of carprofen and its derivatives starting from cyclohexanone are disclosed.
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Paragraph 0083
(2016/11/24)
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- Reversed-phase high-performance liquid chromatographic separation of some 2-arylpropionic acids using vancomycin as chiral stationary phase
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Abstract A rapid, sensitive and reproducible HPLC method has been developed for enantioseparation of six non-steroidal anti-inflammatory drugs, which are acidic compounds: carprofen, fenoprofen, flurbiprofen, ibuprofen, indoprofen and ketoprofen. The effects of the mobile phase composition on retention times and resolutions of the analytes were studied. A column based on vancomycin immobilized by reductive amination to aldehyde functionalised silica was prepared in house and used. The prepared sorbent shows a great stability and selectivity over a range of pH (4-6), and the separation was carried out using the mobile phase composed of a mixture of 40% of methanol in ammonium nitrate buffer (50 mM) at pH 5.0. Another mobile phase consisted of 50% of methanol in phosphate buffer (5A mM) at pH 5.0 was also prepared and tested. The two mobile phases are the optimum conditions obtained. All experiments were conducted at flow rate 0.6 ml/min, using a UV detector wavelength at λ = 254 nm.
- Bouchair, Nabila,Righezza, Michel,Hamdi, Abderrezak
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p. 921 - 928
(2015/05/05)
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- Conventional chiralpak ID vs. capillary chiralpak ID-3 amylose tris-(3-chlorophenylcarbamate)-based chiral stationary phase columns for the enantioselective HPLC separation of pharmaceutical racemates
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A comparative enantioselective analysis using immobilized amylose tris-(3-chlorophenylcarbamate) as chiral stationary phase in conventional high-performance liquid chromatography (HPLC) with Chiralpak ID (4.6mm ID×250mm, 5μm silica gel) and micro-HPLC with Chiralpak ID-3 (0.30mm ID×150mm, 3μm silica gel) was conducted. Pharmaceutical racemates of 12 pharmacological classes, namely, α- and β-blockers, anti-inflammatory drugs, antifungal drugs, dopamine antagonists, norepinephrine-dopamine reuptake inhibitors, catecholamines, sedative hypnotics, diuretics, antihistaminics, anticancer drugs, and antiarrhythmic drugs were screened under normal phase conditions. The effect of an organic modifier on the analyte retentions and enantiomer recognition was investigated. Baseline separation was achieved for 1-acenaphthenol, carprofen, celiprolol, cizolirtine carbinol, miconazole, tebuconazole, 4-hydroxy-3-methoxymandelic acid, 1-indanol, 1-(2-chlorophenyl)ethanol, 1-phenyl-2-propanol, flavanone, 6-hydroxyflavanone, 4-bromogluthethimide, and pentobarbital on the 4.6mm ID packed with a 5μm silica column using conventional HPLC. Nonetheless, baseline separation was achieved for aminoglutethimide, naftopidil, and thalidomide on the 0.3mm ID packed with a 3μm silica capillary column. Chirality 26:677-682, 2014.
- Ahmed, Marwa,Gwairgi, Marina,Ghanem, Ashraf
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p. 677 - 682
(2015/03/31)
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- Identification and characterization of carprofen as a multitarget fatty acid amide hydrolase/cyclooxygenase inhibitor
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Pain and inflammation are major therapeutic areas for drug discovery. Current drugs for these pathologies have limited efficacy, however, and often cause a number of unwanted side effects. In the present study, we identify the nonsteroidal anti-inflammatory drug carprofen as a multitarget-directed ligand that simultaneously inhibits cyclooxygenase-1 (COX-1), COX-2, and fatty acid amide hydrolase (FAAH). Additionally, we synthesized and tested several derivatives of carprofen, sharing this multitarget activity. This may result in improved analgesic efficacy and reduced side effects (Naidu et al. J. Pharmacol. Exp. Ther.2009, 329, 48-56; Fowler, C. J.; et al. J. Enzyme Inhib. Med. Chem.2012, in press; Sasso et al. Pharmacol. Res.2012, 65, 553). The new compounds are among the most potent multitarget FAAH/COX inhibitors reported so far in the literature and thus may represent promising starting points for the discovery of new analgesic and anti-inflammatory drugs.
- Favia, Angelo D.,Habrant, Damien,Scarpelli, Rita,Migliore, Marco,Albani, Clara,Bertozzi, Sine Mandrup,Dionisi, Mauro,Tarozzo, Glauco,Piomelli, Daniele,Cavalli, Andrea,De Vivo, Marco
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p. 8807 - 8826,20
(2020/09/16)
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- COX-2 selective carprofen for treating pain and inflammation in dogs
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Treating or preventing inflammatory processes and diseases in dogs associated with the activity of inducible cyclo-oxygenase-2 (COX-2), while at the same time reducing or eliminating undesirable side effects associated with simultaneous inhibition of the activity of constitutive cyclo-oxygenase-1 (COX-1) by selectively inhibiting COX-2 activity with reference to COX-1 activity, wherein the selectivity ratio or COX-2:COX-1 activity inhibition is at least 3:1 based on ex vivo inhibition levels measured in whole blood; the inhibitor is a member selected from the group of anti-inflammatory compounds consisting essentially of salicylic acid derivatives, p-aminophenol derivatives, indole and indene acetic acids, heteroaryl acetic acids, arylpropionic acids, anthranilic acids, enolic acids, and alkanones; the inhibitor in particular is comprised of (+)(S)-enantiomer of 6-chloro-α-methyl-9H-carbazole-2-acetic acid.
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- Isolation and identification of an unusual impurity in an intermediate of Rimadyl (carprofen)
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The isolation and identification of an unknown process related impurity in a key intermediate of Rimadyl (carprofen) is described. The structure of the unknown was evaluated by NMR spectral analysis and eventually confirmed by single crystal X-Ray. A re-slurry in warm acetic acid was found to reduce the level of the unknown to an acceptable level.
- Tucker, John L.,DeVries, Keith M.,Hammen, Philip D.,Rose, Peter R.,Raymer, Brian K.,Rescek, Diane
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p. 1681 - 1688
(2007/10/03)
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- Effect of micelles and mixed micelles on efficiency and selectivity of antibiotic-based capillary electrophoretic enantioseparations.
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Vancomycin (an oligophenolic, glycopeptide, macrocyclic antibiotic) has been shown to be a superb chiral selector for anionic and neutral compounds. It was found that adding sodium dodecyl sulfate to the run buffer increased efficiency by over 1 order of magnitude, decreased analysis times, and reversed the elution order of the enantiomers. This allows for control of the retention order as well as the resolution of enantiomers in complex mixtures in a single run. A mechanism is proposed which explains all of the observed effects and is verified experimentally. Since vancomycin is present in both the micelle and in free solution, previously proposed micelle-selector models are, at best, limiting cases. A general equation is derived which can be used to describe all possible interactions, including those with the capillary wall, if needed. Also, it is shown that electrophoretic mobilities and not migration times must be used to calculate binding constants of a solute to the micelle, the chiral selector, or both. Furthermore, it is shown that a neutral marker molecule cannot be used to accurately correct mobilities that have been altered due to changes in solution viscosity. While this work utilizes the practical vancomycin-micelle system, the general conclusions and theory apply to most other analogous CE systems as well.
- Rundlett,Armstrong
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p. 2088 - 2095
(2007/10/02)
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- Syntheses of Carprofen, A Carbazole-Based Nonsteroidal Anti-Inflammatory Agent
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Syntheses of carprofen (6) have been achieved by two approaches from carbazole (11).In one, 2,9-diacetylcarbazole (12) and 2-acetylcarbazole (13) were chlorinated with trichloroisocyanuric acid (15) to give the 6-chloro derivatives (16) and (17), respectively.Reduction of 16 with NaBH4, followed by acetylation, cyanide displacement, and hydrolysis afforded 6 in 73percent yield from 16.Alternatively, 17 was converted into its trimethylsilyloxy cyanohydrin derivative (27), which was reduced with SnCl2 and hydrolysed to give 6 in 75percent yield from 17.In the other approach, the ketone (18), derived by a Friedel-Crafts acylation of 9-acetylcarbazole with 2-chloropropanoyl chloride followed by chlorination with 15, was converted into the hydroxyketal (28) with methanolic NaOMe.Mesylation of 28, followed by a modified Favorskii rearrangement and hydrolysis gave 6 in 73percent yield from 18.
- Manchand, Percy S.,Coffen, David L.,Belica, Peter S.,Wong, Frederick,Wong, Harry S.,Berger, Leo
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p. 833 - 846
(2007/10/02)
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- High molecular weight prodrug derivatives of antiinflammatory drugs
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Compounds of the formula 1, PS - O - A - (CH2)n- B - D (1), wherein PS-O represents an alkoxide residue of any of the free hydroxy groups of a polysaccharide (PS-OH) compound with molecular weight (Mw) of from 40,000 to 5,000,000 selected from dextran, carboxymethyl dextran, diethylaminoethyl dextran, starch, hydroxyet-hyl starch, alginates, glycogen, pullullan, agarose, cellulose, chitosan, chitin and carrageenan,A is a carbonyl group or absent,n is zero or a positive integer from 1 to 14,B is oxygen, a carbonyl group, NR wherein R is hydrogen or lower alkyl, or B is absent, and, D is (i) a group of the formula:, R1 - CO - (11), wherein R1-CO- represents the acyl residue of a carboxylic acid drug (R1-COOH) used in the treatment of inflammatory disorders; or (ii) a group of the formula:, R2 - O - (12), wherein R2-O- refers to the C-21 alkoxide residue of a known antiinflammatory steroid (R2-OH) or an alkoxide residue of any other drug or medicament containing a hydroxy functional group used in the treatment of inflammatory disorders; with the proviso that when A is absent, n is 0, and B is absent, then R1-CO- is different from the acyl residue of acetylsalicylic acid;, and non-toxic pharmaceutically acceptable acid addition salts thereof;, and non-toxic pharmaceutically acceptable cation salts thereof. Such compounds are biolabile prodrugs providing controlled release and prolonged duration of action of the parent active antiinflamma-tory agents locally at the administration site after intra-articular, intra-muscular, subcutaneous or extra-dural application while at the same time being highly stable in aqueous solution in the pH range 3--5. After oral administration of such prodrugs the parent drug is liberated selectively in the terminal ileum and the colon over an extended period of time.
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- Derivatives of antiphlogistically effective carboxylic acids, their preparation and medicinal use
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Compounds of Formula I STR1 wherein R1 is the residue of an antiphlogistically effective carboxylic acid of the formula R1 COOH, n is an integer 1, 2, or 3, and X is oxygen, sulfur, or optionally alkylated nitrogen have valuable antiinflammatory activity.
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- Esters and amides containing the 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetyl moiety
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Compounds of the formula STR1 wherein each X, which may be identical or different from the other X, is oxygen or imino; R1 is hydrogen, fluorine, chlorine or bromine; R2 and R3, which may be identical or different from each other, are each hydrogen; unsubstituted or mono-substituted alkyl of 1 to 6 carbon atoms, where the substituent is phenyl or dialkylamino with 1 to 3 carbon atoms in each alkyl moiety; pyridyl; or cycloalkyl of 5 to 7 carbon atoms; R2 and R3, together with each other and the nitrogen atoms to which they are attached, are pyrrolidino, piperidino, hexamethyleneimino, morpholino, N-aryl-piperazino or N-(alkyl of 1 to 3 carbon atoms)-piperazino; A is cycloalkylene of 5 to 7 carbon atoms; unsubstituted or substituted alkylene of 2 to 10 carbon atoms, where the substituents are one to two alkyls of 1 to 3 carbon atoms each, one to two carbalkoxys of 2 to 4 carbon atoms each, one to two phenyls, one to four hydroxyls, one halomethyl, one hydroxymethyl, one alkanoyloxy of 1 to 18 carbon atoms, one alkanoyloxymethyl of 1 to 18 carbon atoms in the alkanoyl moiety or one STR2 where R1, R2 and R3 have the meanings previously defined; or alkylene of 2 to 10 carbon atoms interrupted by oxygen, sulfur, sulfoxide, sulfonyl, phenyl, cyclohexyl, pyridyl, piperazino or unsubstituted or substituted imino, where the substituent on the imino group is alkyl of 1 to 6 carbon atoms, phenyl or phenylalkyl of 1 to 3 carbon atoms in the alkyl moiety; B is the acyl residue of an antiphlogistic carboxylic acid; and their non-toxic, pharmacologically acceptable acid addition salts. The compounds as well as their salts are useful as anti-inflammatories.
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- Process of making 6-chloro-α-methyl-carbazole-2-acetic acid
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The aromatization of (6-chloro-1,2,3,4-tetrahydro-2-carbazolyl)-methyl-malonic acid dialkyl ester, utilizing chlorine and subsequent conversion of the resulting product to 6-chloro-α-methyl-carbazole-2-acetic acid by hydrolysis and decarboxylation are described.
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- Carbazole methyl malonates
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A process for the preparation of α-methyl-carbazole-2-acetic acids, which comprises reacting an α-methyl-3-oxocyclohexane malonic acid di-lower alkyl ester with a substituted phenylhydrazine, and thereafter sequentially oxidizing and hydrolyzing the reaction product to obtain the desired acid, is described.
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- Hydroxy methyl carbazole acetic acid and esters
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A process for the preparation of 6-chloro-α-methylcarbazole-2-acetic acid from 6-chloro-α-hydroxy-α-methylcarbazole-2-acetic acid and/or 6-chloro-α-methylene-2-carboxylic acid, is described. The preparation of intermediates, such as, 6-chloro-α-hydroxy-α-methylcarbazole-2-acetic acid and lower alkyl carbazole-2-oxalate, inter alia, is also described.
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