- Orthoester in Cyclodehydration of Carbamate-Protected Amino Alcohols under Acidic Conditions
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The first acid-promoted reaction system to form azaheterocycles from N -carbamate-protected amino alcohols is described. The reaction involves the activation of the hydroxyl group via the use of orthoesters. Despite the reduced nucleophilicity of carbamate nitrogen, this reaction system provides several types of pyrrolidines and piperidines in good to high yields. Using this protocol, prolinol derivatives can also be synthesized from carbamate-protected amino diols with regio- and stereoselectivity.
- Park, Heemin,Kwon, Yongseok,Shin, Jae Eui,Kim, Woo-Jung,Hwang, Soonho,Lee, Seokwoo,Kim, Sanghee
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supporting information
p. 2761 - 2767
(2017/06/13)
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- Isolation and total syntheses of two new alkaloids, dubiusamines-A, and -B, from Pandanus dubius
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Chemical investigation of the crude base of Pandanus dubius led to the isolation of two new alkaloids, dubiusamine-A (1) and dubiusamine-B (2). The structures of the two alkaloids including their absolute configuration were unambiguously confirmed by 1D a
- Tan, Mario A.,Kitajima, Mariko,Kogure, Noriyuki,Nonato, Maribel G.,Takayama, Hiromitsu
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scheme or table
p. 3353 - 3359
(2010/06/17)
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- PYRAZOLE DERIVATIVE
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A compound represented by Formula (I): wherein Ar1 represents Formula (II): Ar2 represents a 5- or 6-membered aromatic heterocyclic group which may be substituted; and X represents Formula (III): a salt thereof, or a solvate of the compound or the salt. A potent platelet aggregation suppressant which does not inhibit COX-1 and COX-2 is provided.
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Page/Page column 70
(2010/11/27)
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- Chemoenzymatic synthesis and inhibitory activities of hyacinthacines A 1 and A2 stereoisomers
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A novel straightforward chemoenzymatic procedure for the synthesis of hyacinthacine stereoisomers based on the aldol addition of dihydroxyacetone phosphate (DHAP) to N-Cbz-prolinal under catalysis by L-rhamnulose 1-phosphate aldolase from E. coli is prese
- Calveras, Jordi,Casas, Josefina,Parella, Teodor,Joglar, Jesus,Clapes, Pere
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p. 1661 - 1666
(2008/02/11)
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- INDANOL DERIVATIVE
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The present invention provides a compound having the following general formula (I) which is useful as a neurokinin receptor antagonist: (wherein, R1, R2: optionally substituted (hetero)aryl, R3: -CO-R4, -CO-O-R4, etc., R4: alkyl, cycloalkyl, etc., A: CH2, CO, SO2, B: a single bond, etc., D: oxygen, CH2, E: alkylene, alkenylene, n: 1 to 3).
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Page/Page column 79-80
(2010/11/25)
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- Enzyme-catalyzed enantiomeric resolution of N-Boc-proline as the key-step in an expeditious route towards RAMP
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For the preparation of both enantiomers of N-carbamoyl-2-methoxymethylpyrrolidine, the precursors of Enders' chiral auxiliaries, SAMP and RAMP, enzyme-catalyzed kinetic resolution of racemic N-carbamoyl, N-Boc, N-Cbz proline esters and prolinols were examined. B. licheniformis protease (subtilisin) preferentially hydrolyzed the (R)-carbamoylproline ester with an enantiomeric ratio (E) of 10. To a hydrophobic N-Cbz proline ester, subtilisin showed lower selectivity (E=2.8), and in contrast, a purified protease (isozyme A) from the earthworm showed the preference of (S)-enantiomer (E=13.6). In a practical sense, C. antarctica lipase B (Chirazyme L-2) was effective for the hydrolysis of both N-Boc and N-Cbz derivatives with E >100. The e.e. of (R)-N-carbamoyl-2-methoxymethylpyrrolidine was raised to be >99.9% by recrystallization at the N-Boc-prolinol stage, which was derived from the (R)-N-Boc-proline methyl ester (98.7% e.e.) through a preparative-scale enzyme-catalyzed resolution (49% yield) of the racemic substrate.
- Kurokawa, Masayuki,Shindo, Takeyuki,Suzuki, Masumi,Nakajima, Nobuyoshi,Ishihara, Kohji,Sugai, Takeshi
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p. 1323 - 1333
(2007/10/03)
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- Synthesis and cholinergic affinity of diastereomeric and enantiomeric isomers of 1-methyl-2-(2-methyl-1,3-dioxolan-4-yl)- pyrrolidine, 1-methyl-2-(2-methyl-1,3-oxathiolan-5-yl)pyrrolidine and of Their iodomethylates
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Four out of the eight possible stereoisomers of 1-methyl-2-(2-methyl-1,3-dioxolan-4-yl)pyrrolidine, 1-methyl-2-(2-methyl-1,3-oxathiolan-5-yl)pyrrolidine and the corresponding iodomethylates have been synthesised. They were formally derived from hybridisat
- Dei, Silvia,Bellucci, Cristina,Buccioni, Michela,Ferraroni, Marta,Gualtieri, Fulvio,Guandalini, Luca,Manetti, Dina,Matucci, Rosanna,Romanelli, Maria Novella,Scapecchi, Serena,Teodori, Elisabetta
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p. 3153 - 3164
(2007/10/03)
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- Enantiospecific syntheses of (R)- and (S)-proline and some derivatives from D-glucono-1,5-lactone
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Carbohydrate-based enantiospecific syntheses of (R)-proline 1 and (S)-proline 2 from the previously reported D-erythro-hexonate ester 9 are described. Azide-substitution reactions on appropriately activated intermediates derived from ester 9, followed by reductive cyclization (H2/Pd-C), gave the substituted pyrrolidines 14 and 22, which were converted into their corresponding N-Cbz derivatives 16 and 24 in conventional manner. Mild acidic hydrolysis of these, followed by oxidation (sodium metaperiodate), gave the protected prolinals 3 and 4, which on further oxidation (sodium chlorite), followed by catalytic hydrogenolysis, gave the prolines 1 and 2. The N-Cbz-prolinol derivatives 5 and 6 are also reported.
- Mazzini, Claudio,Sambri, Letitia,Regeling, Henk,Zwanenburg, Binne,Chittenden, Gordon J. F.
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p. 3351 - 3356
(2007/10/03)
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- Substituted oxotremorine derivatives and pharmaceutical use thereof
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This disclosure describes novel substituted oxotremorine derivatives of formula I having nitrogen, oxygen or sulfur groups and the prodrug forms of these derivatives. The compounds have cholinergic activity. Also disclosed are methods for treating disease
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- The synthesis of a conformationally restricted analog of the anti-migraine drug sumatriptan
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The synthesis of 5-N-Methylaminosulfonylmethyl-3-(N-methylpyrrolidin-2-ylmethyl)indole (1), a conformationally restricted analog of the anti-migraine drug, sumatriptan, is described. To incorporate our novel stereogenic replacement for the aminoethyl side
- Macor,Blank,Post,Ryan
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p. 8011 - 8014
(2007/10/02)
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