- PROCESS FOR THE PREPARATION OF FLUOROACRYLIC ACID ESTERS
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The present invention provides a process for the preparation of a compound of Formula VI.
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Page/Page column 8; 10
(2017/02/24)
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- Method for the preparation of compounds
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The invention provides a preparation method of a compound as described in the formula 1. The method comprises the steps of (1) contacting a compound as described in the formula 2 and a compound as described in the formula 3 in the existence of alkali to obtain a compound as described in the formula 4; and (2) directly contacting a reaction product obtained in the step (1) and paraformaldehyde to obtain the compound as described in the formula 1, wherein weak acid is added in the reaction product before the reaction product obtained in the step (1) is in contact with the paraformaldehyde so that the residual alkali in the reaction product can be neutralized. By using the method, the compound as described in the formula 1 can be effectively prepared.
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Paragraph 0106; 0107; 0108; 0109; 0110; 0111; 0112
(2017/04/03)
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- Preparation of α-haloacrylate derivatives via dimethyl sulfoxide-mediated selective dehydrohalogenation
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(Chemical Equation Presented) Dimethyl sulfoxide causes α/β-dihalopropanoate derivatives to undergo efficient, selective dehydrohalogenation to form α-haloacrylate analogues. A variety of α-halo Michael acceptors were prepared in dimethyl sulfoxide under mild, base-free conditions, including the preparation of α-bromoacrolein and α-chloro- and bromoacrylonitriles. Synthesis of these molecules has been reported in the literature to be difficult. Among all the existing dehydrohalogenation procedures, this protocol is the most facile, practical, and environmentally benign process.
- Li, Wei,Li, Jianchang,Wan, Zhao-Kui,Wu, Junjun,Massefski, Walter
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p. 4607 - 4610
(2008/03/13)
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- Synthesis and oxidative fragmentation of catharanthine analogs. Comparison to the fragmentation - Coupling of catharanthine and vindoline
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Two new analogs of catharanthine have been synthesized in racemic form. They differ from catharanthine in the fusion of the indole ring to the non- aromatic portion of the iboga skeleton, with the [2,3] fusion present in catharanthine being replaced by [2,1] and [3,2] fusions. The corresponding deethyl analogs were also and methodological improvements were applied to an existing synthesis of deethylcatharanthine and a formal synthesis of racemic catharanthine. The reactivity of the catharanthine analogs toward coupling with vindoline was examined. Coupling was attempted by both the amine oxide fragmentation (Potier) and Fe3+ methods. Under Potier conditions the [2,1] fused analogs give low yields of coupling products in which vindaline is attached to the 3-position of the indole ring. The [3,2] isomers undergo fragmentation of the C16-C21 bond, as observed for catharanthine, but no coupling to vindoline occurs. The reactivity, oxidation potentials and conformation of the analogs are compared with catharanthine, deethylcatharanthine and N-methylcatharanthine.
- Sundberg, Richard J.,Hong, Jian,Smith, Stanton Q.,Sabat, Michal,Tabakovic, Ibro
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p. 6259 - 6292
(2007/10/03)
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- Zinc promoted addition of methyl 2,2-dihalocarboxylates to carbonyl compounds
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Methyl 2,2-dihalocarboxylates add easily to carbonyl compounds in fair to good yields through the intermediate formation of 2-haloester enolates; the reaction is promoted by zinc, following a "Barbier" type procedure.
- Benincasa, Marta,Forti, Luca,Ghelfi, Franco,Libertini, Emanuela,Pagnoni, Ugo M.
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p. 4113 - 4122
(2007/10/03)
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- Stereoselective dehydrobromination of alkyl α-Br α-Cl-carboxylates
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(Z)-Alkyl α-Cl-α,β-unsaturated esters are prepared in excellent yields by stereoselective dehydrobromination of alkyl α-Br-α-Cl-carboxylates with LiCl-Li2CO3 in dimethylformamide.
- Forti, Luca
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p. 3023 - 3026
(2007/10/02)
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- Synthesis of α-Halocinnamate Esters via Solvolytic Rearrangement of Trichloroallyl Alcohols
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Aryl trichlorovinyl ketones undergo regioselective reduction to the corresponding carbinols with sodium borohydride in alcoholic solvents and are transformed to the (Z)-α-chlorocinnamate ester derivatives via an acid-catalyzed allylic rearrangement.Micharl addition of ammonia to these ester derivatives affords cis- and/or trans-aziridine amides.The facile rearrangement allows the synthesis of d,l-phenylalanine derived from perchloroethylene and toluene.
- Kruper, William J.,Emmons, Albert H.
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p. 3323 - 3329
(2007/10/02)
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- Process for the preparation of α-halocinnamate esters
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Prepare esters of α-halocinnamic acid and related compounds in high yield under relatively mild conditions.
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- ISOMERIZATION OF 5-ACYL-6-HALO-1,6-DIAZABICYCLOHEXANES, A CASE OF INVERSION RATHER THAN 1,2-ACYL MIGRATION
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X-ray diffraction structural analysis and 13 C and 15 N NMR spectroscopy were used to establish that the final product of the halogenation of 5-acyl-1,6-diazabicyclohexane is the oxo-6-halo derivative.Thus, the observed transformation of the initially formed endo-N-chloro isomer is an inversion and not 1,2-acyl migration as previously proposed.
- Shustov, G. V.,Denisenko, S. N.,Chervin, I. I.,Zolotoi, A. B.,D'yachenko, O. A.,et all
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p. 1076 - 1079
(2007/10/02)
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- HALOGENATION OF UNSATURATED ESTERS-II. ADDITION OF Cl2, BrCl AND Br2 TO METHYL ESTERS OF MONOCHLOROPROPENOIC ACIDS
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The addition of chlorine, bromine chloride and bromine to methyl 2-chloropropenoate 1, methyl cis-3-chloropropenoate 2 and methyl trans-3-chloropropenoate 3 under ionic and radical conditions gave regioisomer mixtures.Both trans- and cis-addition of halogen species was observed, bromine preferentially adding to the non-halogenated carbon atom.
- Pitkaenen, Maija,Korhonen, Ilpo O. O.
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p. 3367 - 3372
(2007/10/02)
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