7529-16-0Relevant articles and documents
Synthesis of Lactams via Ir-Catalyzed C-H Amidation Involving Ir-Nitrene Intermediates
Li, Xiaoxun,Liu, Jitian,Tang, Weiping,Wang, Shuojin,Ye, Wenjing,Zheng, Junrong
, (2020/03/19)
x-membered lactams were synthesized via either an amidation of sp3 C-H bonds or an electrophilic substitution of arenes via Ir-nitrene intermediates. With the employment of a readily available iridium catalyst in dichloromethane or hexafluoro-2-propanol, a wide range of lactams were synthesized in good to excellent yields with high selectivity.
A convenient approach for vinylation reaction in the synthesis of 5-vinyl-2-pyrrolidinone, a key intermediate of vigabatrin
Karumanchi, Kishore,Natarajan, Senthil Kumar,Gadde, Sunil,Vanchanagiri, Krishna
, p. 2035 - 2039 (2020/01/02)
A convenient, safe and cost-effective method for carrying out the key vinylation of 5-ethoxy-2-pyrrolidinone (8) in the preparation of 5-vinyl-2-pyrrolidinone (2) in the presence of potassium carbonate is described. This present procedure is developed by replacing inherently hazardous ethyl magnesium bromide with inexpensive and eco-friendly potassium carbonate. The reaction was performed on a multi-gram scale, with vinyl magnesium bromide as the vinylation reagent, in an 81% yield to give the 5-vinyl-2-pyrrolidinone with excellent purity and without the need for chromatography.
A PROCESS FOR THE PREPARATION OF VIGABATRIN
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Page/Page column 5; 6, (2019/10/15)
The present invention provides a process for the preparation of vigabatrin of formula (I) comprising of dissolving vigabatrin in water, optionally treating with charcoal, filtering and adding an acid to the reaction mass followed by the addition of an organic solvent and then isolating vigabatrin of formula (I) with high purity.
Ruthenium(II)-Catalyzed Enantioselective ?-Lactams Formation by Intramolecular C-H Amidation of 1,4,2-Dioxazol-5-Ones
Xing, Qi,Chan, Chun-Ming,Yeung, Yiu-Wai,Yu, Wing-Yiu
, (2019/03/11)
We report the Ru-Catalyzed enantioselective annulation of 1,4,2-Dioxazol-5-Ones to furnish ?-Lactams in up to 97% yield and 98% ee via intramolecular carbonylnitrene C-H insertion. By employing chiral diphenylethylene diamine (dpen) as ligands bearing electron-Withdrawing arylsulfonyl substituents, the reactions occur with remarkable chemo- A nd enantioselectivities; the competing Curtius-Type rearrangement was largely suppressed. Enantioselective nitrene insertion to allylic/propargylic C-H bonds was also achieved with remarkable tolerance to the Ca?C and Ca‰iC bonds.
Ruthenium(II)-Catalyzed Enantioselective γ-Lactams Formation by Intramolecular C-H Amidation of 1,4,2-Dioxazol-5-ones
Xing, Qi,Chan, Chun-Ming,Yeung, Yiu-Wai,Yu, Wing-Yiu
, p. 3849 - 3853 (2019/04/25)
We report the Ru-catalyzed enantioselective annulation of 1,4,2-dioxazol-5-ones to furnish γ-lactams in up to 97% yield and 98% ee via intramolecular carbonylnitrene C - H insertion. By employing chiral diphenylethylene diamine (dpen) as ligands bearing electron-withdrawing arylsulfonyl substituents, the reactions occur with remarkable chemo- and enantioselectivities; the competing Curtius-type rearrangement was largely suppressed. Enantioselective nitrene insertion to allylic/propargylic C - H bonds was also achieved with remarkable tolerance to the C=C and C=C bonds.
Synthetic method for novel vigabatrin intermediate
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Paragraph 0040; 0041; 0042; 0043; 0044; 0045; 0046-0059, (2018/05/16)
The invention relates to a synthetic method for a novel vigabatrin intermediate. According to the invention, through changing of a feeding manner of a reaction, the content of impurities is significantly reduced, and the yield and product purity are improved; meanwhile, through changing of a post-treatment manner, the step of extraction is removed, and the volume of reduced pressure distillation is reduced, so process operations and a solvent amount are significantly reduced, and environmental pollution and cost can be easily reduced. To sum up, compared with the prior art, the synthetic method provided by the invention has the advantages of short period, low cost, simple operation, low environmental pollution, and applicability to industrial production.
Selective formation of γ-lactams via C-H amidation enabled by tailored iridium catalysts
Hong, Seung Youn,Park, Yoonsu,Hwang, Yeongyu,Kim, Yeong Bum,Baik, Mu-Hyun,Chang, Sukbok
, p. 1016 - 1021 (2018/03/09)
Intramolecular insertion of met al nitrenes into carbon-hydrogen bonds to form γ-lactam rings has traditionally been hindered by competing isocyanate formation. We report the application of theory and mechanism studies to optimize a class of pentamethylcyclopentadienyl iridium(III) catalysts for suppression of this competing pathway. Modulation of the stereoelectronic properties of the auxiliary bidentate ligands to be more electron-donating was suggested by density functional theory calculations to lower the C-H insertion barrier favoring the desired reaction. These catalysts transform a wide range of 1,4,2-dioxazol-5-ones, carbonylnitrene precursors easily accessible from carboxylic acids, into the corresponding γ-lactams via sp3 and sp2 C-H amidation with exceptional selectivity. The power of this method was further demonstrated by the successful late-stage functionalization of amino acid derivatives and other bioactive molecules.
Synthesis of γ-Lactams by Mild, o-Benzoquinone-Induced Oxidation of Pyrrolidines Containing Oxidation-Sensitive Functional Groups
Rong, Hao-Jie,Cheng, Yong-Feng,Liu, Fan-Fan,Ren, Shu-Jian,Qu, Jin
, p. 532 - 540 (2017/04/26)
The late-stage oxidation of substituted pyrrolidines offers good flexibility for the construction of γ-lactam libraries, and especially in recent years the methods for functionalization of pyrrolidine have been available. We reported a new strategy for oxidation of pyrrolidines to γ-lactams: reaction of pyrrolidine with an o-benzoquinone gives an N,O-acetal by direct oxidation of the α-C-H bond of the pyrrolidine ring, and then the N,O-acetal is further oxidized by the o-benzoquinone to the γ-lactam. Because the first oxidation occurs selectively at the α-C-H of the pyrrolidine ring, oxidation-sensitive functional groups (allyl-, vinyl-, hydroxyl-, and amino groups) on pyrrolidine ring are unaffected. The synthetic utility of this novel method was demonstrated by the facile syntheses of (S)-vigabatrin and two analogues.
Process for preparing 4-amino-5-hexenoic acid from succinimide
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Page/Page column 9-10, (2013/02/28)
The present invention relates to a competitive process for the preparation of 4-amino-5-hexenoic acid and intermediates thereof. This compound is a well-known anti-epileptic drug for which several syntheses have been developed, all of them presenting drawbacks. The preparation process according to the present invention is very competitive from an economical point of view and is adapted to industrial scale preparation of 4-amino-5-hexenoic acid.
Cobalt-catalyzed coupling of alkyl iodides with alkenes: Deprotonation of hydridocobalt enables turnover
Weiss, Matthias E.,Kreis, Lukas M.,Lauber, Alex,Carreira, Erick M.
supporting information; experimental part, p. 11125 - 11128 (2012/02/02)
Completing the cycle: Cobalt complexes I and II were found to catalyze intramolecular alkyl Heck-type coupling reactions of alkyl iodides to alkenes upon irradiation with visible light in the presence of a tertiary amine base. The use of base is key to the catalytic turnover. The compatibility of the method with a broad range of functional groups opens opportunities for synthesis. Copyright