- Rapid Multigram-Scale End-to-End Continuous-Flow Synthesis of Sulfonylurea Antidiabetes Drugs: Gliclazide, Chlorpropamide, and Tolbutamide
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A multigram-scale robust, efficient, and safe end-to-end continuous-flow process for the diabetes sulfonylurea drugs gliclazide, chlorpropamide, and tolbutamide is reported. The drugs were prepared by the treatment of an amine with a haloformate affording carbamate, which was subsequently treated with a sulfonamide to afford sulfonylurea. Gliclazide was obtained in 87% yield within 2.5 minutes total residence time with 26 g/h throughput; 0.2 kg of the drug was produced in 8 hours of running the system continuously. Chlorpropamide and tolbutamide were both obtained in 94% yield within 1 minute residence time with 184-188 g/h throughput; 1.4-1.5 kg of the drugs was produced in 8 hours of running the system continuously. N-Substituted carbamates were used as safe alternatives to the hazardous isocyanates in constructing the sulfonyl urea moiety.
- Sagandira, Cloudius R.,Watts, Paul
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supporting information
(2021/12/02)
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- Synthesis, cytotoxicity, and in vivo antitumor activity study of parthenolide semicarbazones and thiosemicarbazones
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Parthenolide is an important sesquiterpene lactone with potent anticancer activities. In order to further improve its biological activity, a series of parthenolide semicarbazone or thiosemicarbazone derivatives was synthesized and evaluated for their anti
- Du, Guohua,Jia, Xinxin,Li, Yan,Liu, Qi,Wang, Shiyi,Zeng, Binglin,Zhang, Chen
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- A facile synthesis of sulfonylureas: Via water assisted preparation of carbamates
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A novel and simple approach to the synthesis of sulfonylureas has been reported. It involved the reaction of various amines with diphenyl carbonate to yield the corresponding carbamates, which subsequently reacted with different sulphonamides to produce different sulfonylureas in excellent yields. The first reaction of diphenyl carbonate with amines was carried out in aqueous:organic (H2O:THF, 90:10) medium at room temperature to produce carbamates that paved a straightforward route to sulfonylureas after reaction with sulfonamides. The above process avoided traditional multistep protocols and the use of hazardous, irritant, toxic and moisture sensitive reagents such as phosgene, isocyanates and/or chloroformates.
- Tanwar, Dinesh Kumar,Ratan, Anjali,Gill, Manjinder Singh
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p. 4992 - 4999
(2017/07/11)
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- Sustainable synthesis routes towards urazole compounds
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Sustainable synthesis routes towards urazoles, the precursor molecules for triazolinediones, are reported. Not only is the use of isocyanates avoided, but the applied synthetic procedures are also mostly solvent-free, high yielding and performed in an equimolar manner. Two complementary synthesis routes have been developed starting from a wide range of amines, both based on the use of diphenyl carbonate. The first method, which is particularly suitable for the synthesis of bulk urazoles, such as butyl, cyclohexyl or benzyl urazole, is performed in bulk in a one-pot fashion and generally results in yields between 87% and 96%. The second synthesis route, with yields up to 95%, focusses on the implementation of functionalities in the urazole structure and offers the possibility to generate bifunctional urazole compounds.
- Vlaminck, Laetitia,Van De Voorde, Babs,Du Prez, Filip E.
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supporting information
p. 5659 - 5664
(2017/12/06)
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- Phenyl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylate as carbonyl source: Facile and selective synthesis of carbamates and ureas under mild conditions
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The selective syntheses of carbamates, symmetric -ureas, and unsymmetrical ureas have been accomplished by the -reaction of amines with phenyl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylate as a carbonyl source under mild conditions. It is noteworthy that this process is mild, economic, and convenient.
- Lee, Hyung-Geun,Kim, Min-Jung,Park, Song-Eun,Kim, Jeum-Jong,Kim, Bo Ram,Lee, Sang-Gyeong,Yoon, Yong-Jin
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experimental part
p. 2809 - 2814
(2010/03/03)
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- Concomitant Desulfurization and Transesterification of Alkyl Thionocarbamates
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Alkyl carbamate (such as 1) reacts with triphosgene at the nitrogen atom, whereas the analogous thionocarbamates (5) react at the sulfur. Subsequent treatment with various phenols or alcohols leads to the corresponding aryl carbamates or alkyl carbamates
- Joshi, Uday M.,Patkar, Laxmikant N.,Rajappa, Srinivasachari
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- Nitrogen-containing aromatic derivatives
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Compounds represented by the following general formula: [wherein Ag is an optionally substituted 5- to 14-membered heterocyclic group, etc.; Xg is —O—, —S—, etc.; Yg is an optionally substituted C6-14 aryl group, an optionally substituted 5- to 14-membered heterocyclic group, etc.; and Tg1 is a group represented by the following general formula: (wherein Eg is a single bond or —N(Rg2)—, Rg1 and Rg2 each independently represent a hydrogen atom, an optionally substituted C1-6 alkyl group, etc. and Zg represents a C1-8 alkyl group, a C3-8 alicyclic hydrocarbon group, a C6-14 aryl group, etc.)], salts thereof or hydrates of the foregoing.
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- Ortho effects and cross interaction correlations for the mechanisms of cholesterol esterase inhibition by aryl carbamates
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Ortho-substituted phenyl-N-butyl carbamates (1-11) were synthesized to evaluate the inhibition mechanisms of porcine pancreatic cholesterol esterase. All carbamate inhibitors act as the active site-directed pseudo substrate inhibitors of the enzymes. The logarithms of dissociation constant (K i), carbamylation constant (k2) and bimolecular inhibition constant (ki) multiply linearly correlate with the Hammett substituent constant (σ), the Taft-Kutter-Hansch ortho steric constant (Es), and the Swan-Lupton-Hansch ortho polar constant (F). For the -log Ki, log k2 and log ki correlations, the reaction constant for ordinary polar effect (ρ), the intensity factor to ortho steric constant (δ) and the intensity factor to ortho polar constant (f) are 0.7, -0.07, and 0.5; 0.5, 0.04 and -0.5; and 1.1, -0.03 and 0.0, respectively. The cross interaction reaction constant (ρXR) for the -log ki-, log k2- and log ki-σ- ασ*-ασσ* correlations are 3, -2, and 1, respectively. The Ki step may be composed of the following two steps: (1) protonation of carbamates 1-11 and (2) the pseudo-trans to pseudo-cis conformation change of protonated carbamates 1-11 due to a large ρXR value of 3 and formation of the enzyme-protonated carbamates 1-11 tetrahedral intermediate. The k2 step involves departure of the leaving group, which is protonated by the active site histidine of the enzyme, from the tetrahedral intermediate to solution and formation of the carbamyl enzyme. Moreover, the distances between the carbamate and phenyl groups in all transition states of inhibition reactions are relatively short owing to large |ρXR| values. The Ki step shows little ortho steric enhancement effect; moreover, the k2 step shows little ortho steric inhibition effect. Copyright
- Lin, Gialih,Liu, Yu-Chen,Wu, Yon-Gi,Lee, Yu-Ru
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p. 707 - 714
(2007/10/03)
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- Structure-reactivity relationships as probes for the inhibition mechanism of cholesterol esterase by aryl carbamates. I. Steady-state kinetics
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For substituted phenyl-N-butyl carbamates (1) and 4-nitrophenyl-N-substituted carbamates (2), linear relationships between values of NH proton chemical shift (δNH), pKa, and logk[OH] and Hammett substituent constant (σ) or Taft subst
- Lin, Gialih,Lai, Cheng-Yue,Liao, Wei-Cheng,Kuo, Bing-Hong,Lu, Chun-Ping
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p. 489 - 500
(2007/10/03)
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- Molecular recognition by acetylcholinesterase at the peripheral anionic site: Structure-activity relationships for inhibitions by aryl carbamates
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Substituted phenyl-N-butyl carbamates (1-9Figure 2Chemical structures of carbamates 1-9 and edrophonium.) are potent irreversible inhibitors of Electrophorus electricus acetylcholinesterase. Carbamates 1-9 act as the peripheral anionic site-directed irrev
- Lin, Gialih,Lai, Cheng-Yue,Liao, Wei-Cheng
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p. 2683 - 2689
(2007/10/03)
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- A highly-efficient synthesis of benzoxazine-2,4-diones
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Base-promoted reaction of salicylate esters with isocyanates provides a highly efficient route to benzoxazine-2,4-diones.
- Boontheung, Pinmanee,Perlmutter, Patrick
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p. 2629 - 2630
(2007/10/03)
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- The enhancement of enantioselectivities for lipase-catalyzed reactions by using carbamates
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The enantioselectivity of porcine pancreatic lipase-catalyzed resolution of 1-indanol was enhanced up to 3 fold in the presence of carbamates. The optimum incubation time for 4-nitrophenyl-N-hexyl carbamate and the enzyme was 18 h before this biocatalytic resolution. The optimum concentration of the inhibitor 4-nitrophenyl-N-hexyl carbamate in this resolution was 1% mole equivalent of the substrate 1-indanol.
- Lin, Gialih,Lin, Wen-Yuan,Shieh, Chuen-Tzwu
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p. 8881 - 8884
(2007/10/03)
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- Synthesis and anti-trypanosomal activity of novel 5-nitro-2-furaldehyde and 5-nitrothiophene-2-carboxaldehyde semicarbazone derivatives
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Several novel semicarbazones derivatives were prepared from 5-nitro-2-furaldehyde or 5-nitrothiophene-2-carboxaldehyde, and tested in vitro as potential anti-trypanosomal agents. The compounds were prepared in good to excellent yields in 2-3 steps from readily available starting materials. Some derivatives were found to be active against Trypanosoma cruzi with an activity similar to that of Nifurtimox.
- Cerecetto, Hugo,Di Maio, Rossanna,Ibarruri, Gerardo,Seoane, Gustavo,Denicola, Ana,Peluffo, Gonzalo,Quijano, Celia,Paulino, Margot
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- Hammett Analysis of the Inhibition of Pancreatic Cholesterol Esterase by Substituted Phenyl-N-Butylcarbamate
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Substituted phenyl-N-butylcarbamates (1) as active site-directed irreversible inhibitors of pancreatic cholesterol esterase are investigated for values of the dissociation constant (KI), the carbamylation constant (k2), and the bimol
- Lin, Gialih,Lai, Cheng-Yue
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p. 6117 - 6120
(2007/10/02)
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- α-Haloalkyl Haloformates and Related Compounds 1. A Convenient Synthesis of Carbamates via Chloromethyl Carbamates
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The preparation of carbamates under mild conditions utilizing a new class of activated carbonates (containing chloromethyl function) is described.
- Patonay, Tamas,Patonay-Peli, Erzsebet,Mogyorodi, Ferenc
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p. 2865 - 2885
(2007/10/02)
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- BORON TRICHLORIDE CATALYZED ORTHO CARBONYLATION OF PHENOLS: SYNTHESIS OF 2-HYDROXY-ARYL-CARBOXYAMIDES AND -KETONES.
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In the presence of equimolar quantity of BCl3, phenols 1 react with isocyanates and acyl chlorides to give, usually with good-excellent yields, 2-hydroxy-aryl-carboxy-amides 2 and 2-hydroxy-aryl-ketones 3 respectively.A distinctive behaviour of BCl3 in comparison with other Lewis acids is observed.
- Piccolo, Oreste,Filippini, Lucio,Tinucci, Laura,Valoti, Ermanno,Citterio, Attilio
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p. 885 - 892
(2007/10/02)
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- Process for O-acylating phenol derivatives and acylating compositions for this purpose
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A process is disclosed for preparing a carbamic acid phenyl ester of the formula (I) STR1 wherein R is alkyl having 1 to 8 carbon atoms, aryl, cycloalkyl having 5 or 6 carbon atoms, or aralkyl having 7 to 16 carbon atoms, wherein the aryl, cycloalkyl or aralkyl is unsubstituted or substituted by at least one alkyl group having 1 to 8 carbon atoms; R1 is hydrogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, cyanomethyl, 1,3-dioxolan-2-yl, or carboalkoxyamino wherein the alkoxy group contains 1 to 4 carbon atoms; R2 is hydrogen, halogen, alkyl having 1 to 4 carbon atoms or alkoxy having 1 to 4 carbon atoms; or R1 and R2 form together a carbocyclic ring or a heterocyclic ring fused to the phenyl ring wherein the carbocyclic ring of the heterocyclic ring is unsubstituted or substituted by at least one alkyl having 1 to 8 carbon atoms, which comprises acylating a phenol of the formula (II) STR2 with a compound of the formula (IV) STR3 in the presence of a base. The compounds obtained are valuable intermediates.
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- Process for preparing alkyl isocyanates
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Alkylisocyanates are prepared by reacting a phenol or substituted phenol and phosgene in a halogenated hydrocarbon solvent with aqueous alkali metal hydroxide to produce a corresponding chloroformate, reacting the resulting chloroformate solution with aqueous alkylamine to give a corresponding N-alkylcarbamate which, after solvent is stripped, is then pyrolyzed to yield the alkyl isocyanate. Solvent and the starting phenol may be recovered and recycled to the process.
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