- NOVEL PROCESS FOR THE PREPARATION OF CISATRACURIUM BESYLATE
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The present invention is related to a novel process for the preparation of cisatracurium besylate, more particularly optically and geometrically pure cisatracurium besylate in large scale.
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Page/Page column 7; 11; 12
(2010/11/18)
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- Photochemically induced cyclization of N-[2-(o-styryl)phenylethyl]acetamides and 5-styryl-1-methyl-1,2,3,4-tetrahydroisoquinolines: New total syntheses of 1-methyl-1,2,3,4-tetrahydronaphtho[2,1-f]isoquinolines
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Two new total syntheses of 1-methyl-1,2,3,4-dihydronaphtho[1,2-f]isoquinolines are based on photochemically induced cyclization of N-{2-[(E)-2-phenyl-1-etheynyl]phenylethyl]}acetamides or 1-methyl-5-[(E)-2-phenyl-1-ethenyl]-1,2,3,4-tetrahydroisoquinolines.
- Martínez, Elena,Estévez, Juan C,Estévez, Ramón J,Castedo, Luis
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p. 1981 - 1986
(2007/10/03)
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- A one-pot bicycloannulation method for the synthesis of tetrahydroisoquinoline systems
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A highly effective method for the synthesis of the core indolo[2,3- α]quinolizidine skeleton found in yohimbine is described. The reaction of N- monosubstituted thioamides with bromoalkenoyl chlorides furnishes thioisomunchnones as transient 1,3-dipoles that undergo ready intramolecular cycloaddition across the tethered π-bond to give thio-bicycloannulated products in a one-pot operation. The stereochemical outcome of the intramolecular reaction is the consequence of an endo cycloaddition of the neighboring π-bond across the transient thioisomunchnone dipole. A major limitation of the method is that when a hydrogen is present in the α- position of the thioamide the initially formed thio-N-acyliminium ion undergoes proton loss to produce a S,N-ketene acetal at a faster rate than dipole formation. Treatment of tetrahydro-β-carboline-1-thione with 2- bromooct-7-enoyl chloride followed by reductive removal of sulfur from the cycloadduct resulted in the formation of (±)-alloyohimbanone. Attempts to cycloadd the thioisomunchnone dipole across several nucleophilic π-bonds failed, and instead, products derived from cyclization of the π-bond onto the initially formed thio-N-acyliminium ion were formed. The resulting N,S- ketals were further converted into several tetrahydroisoquinoline alkaloids in good yield.
- Padwa, Albert,Beall, L. Scott,Heidelbaugh, Todd M.,Liu, Bing,Sheehan, Scott M.
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p. 2684 - 2695
(2007/10/03)
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- General asymmetric synthesis of isoquinoline alkaloids. Enantioselective hydrogenation of enamides catalyzed by BINAP-ruthenium(II) complexes
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In the presence of a small amount of RuX2[(R)- or (S)-BINAP] (X = anionic ligand) a wide range of (Z)-2-acyl-1-benzylidene-1,2,3,4- tetrahydroisoquinolines are hydrogenated to give the saturated products in nearly quantitative yields and in high (up to 100%) optical yields. The enamide substrates are selectively prepared by N-acylation of the corresponding 1-benzylated 3,4-dihydroisoquinolines under suitable acylation conditions; some crystalline materials having low solubility are obtained by a second-order Z/E stereomutation technique utilizing the double-bond photolability and lattice energy effects. This asymmetric hydrogenation sets the key stereogenic center in a predictable manner, either R or S flexibly, at the C(1) position of the benzylated tetrahydroisoquinolines. The chiral products are converted by standard functional group modification to tetrahydropapaverine, laudanosine, tretoquinol, norreticuline, etc. Hydrogenation of the simple 1-methylene substrate is used for synthesis of salsolidine. This enantioselective hydrogenation is applied to the synthesis of morphine and its artificial analogues such as morphinans and benzomorphans of either chirality. A mnemonic device is presented for predicting the reactivity and enantiofacial selection of the BINAP-Ru catalyzed hydrogenation. Reaction with BINAP-Rh catalyst proceeds with a lower enantioselectivity and an opposite sense of asymmetric induction.
- Kitamura,Hsiao,Ohta,Tsukamoto,Ohta,Takaya,Noyori
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p. 297 - 310
(2007/10/02)
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- Illicit Heroin Manufacturing Byproducts: Copillary Gas Chromatographic Determination and Structural Elucidation of Narcotine- and Norlaudanosine-Related Compounds
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Capillary gas chromatographic methodology is described for detection of trace quantities of narcotine- and norlaudanosine-related manufacturing impurities in illicit heroin.N-Acetylnornarcotine (2), N-acetylanhydronornarceine (3a,b), 1-acetoxy-N-acetylanhydro-1,9-dihydronornarceine (4a,b),and (E)-3-acrylic acid(5) result from the reaction of narcotine (1) with acetic anhydride.The treatment of norlaudanosine (11a) with acetic anhydride yields N-acetylnorlaudanosine (9).After isolation from thebulk heroin matrix, these impurities, along with morphine, codeine, and thebaine byproducts, are detected by using both fused silica and glass capillary columns in the split mode with flame ionization detection.The syntheses and spectral characterization of these impurities are described.
- Allen, Andrew C.,Cooper, Donald A.,Moore , James M.,Gloger, Manfred,Neumann, Helmut
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p. 2940 - 2947
(2007/10/02)
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