5466-76-2Relevant academic research and scientific papers
Catalytic, Enantioselective C2-Functionalization of 3-Aminobenzofurans Using N-Heterocyclic Carbenes
Barik, Shilpa,Biju, Akkattu T.,Ghosh, Arghya,Shee, Sayan
supporting information, (2020/05/18)
N-Heterocyclic carbene catalyzed enantioselective functionalization of 3-aminobenzofurans at the C2-position was realized using 2-bromoenals as the coupling partner. The reaction proceeds via generation of chiral α,β-unsaturated acylazoliums and follows a
AMIDATION METHOD AND ESTERIFICATION METHOD USING SULFONIC ACID HALIDE
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Paragraph 0038, (2017/01/17)
PROBLEM TO BE SOLVED: To provide a safe and economical method for rapidly synthesizing amides and esters in high yield. SOLUTION: There is provided a method for amidating an amine or a derivative thereof using a sulfonic acid halide, where a sulfonic acid halide is allowed to act as an activator on a carboxylic acid or a derivative thereof to synthesize an active ester, and the active ester is reacted with an amine or a derivative thereof as a nucleophile to amidate the amine or the derivative thereof to obtain a corresponding amide or a derivative thereof. In a similar manner, a sulfonic acid halide is allowed to act as an activator on a carboxylic acid or a derivative thereof to synthesize an active ester, and the active ester is reacted with an alcohol or a derivative thereof as a nucleophile to esterify the alcohol or the derivative thereof to obtain a corresponding ester or a derivative thereof. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2016,JPO&INPIT
Investigation of two- and three-bond carbon–hydrogen coupling constants in cinnamic acid based compounds
Pierens, Gregory K.,Venkatachalam, Taracad K.,Reutens, David C.
, p. 941 - 946 (2016/11/16)
Two- and three-bond coupling constants (2JHC and 3JHC) were determined for a series of 12 substituted cinnamic acids using a selective 2D inphase/antiphase (IPAP)-single quantum multiple bond correlation (HSQMBC) and 1D proton coupled 13C NMR experiments. The coupling constants from two methods were compared and found to give very similar values. The results showed coupling constant values ranging from 1.7 to 9.7 Hz and 1.0 to 9.6 Hz for the IPAP-HSQMBC and the direct 13C NMR experiments, respectively. The experimental values of the coupling constants were compared with discrete density functional theory (DFT) calculated values and were found to be in good agreement for the 3JHC. However, the DFT method under estimated the 2JHC coupling constants. Knowing the limitations of the measurement and calculation of these multibond coupling constants will add confidence to the assignment of conformation or stereochemical aspects of complex molecules like natural products. Copyright
One-pot preparation of phenylpropanoid esters co-catalyzed by boric acid and piperidine
Wang, Huan,Wei, Qing-Yi,Jiang, Hong,Jiang, Zhen-Hua
experimental part, p. 207 - 213 (2012/05/20)
Phenylpropanoid esters, especially those with hydroxyl and/or methoxy groups on the benzene ring, are important medicinal chemicals or intermediates. They are usually prepared by esterification of their corresponding substituted cinnamic acids with various alcohols. However, the esterification procedures often suffer from environmentally hazardous problems when sulfuric acid is used as a catalyst or suffer from unsatisfactory yields and expensive raw material when enzyme is applied as a catalyst. In this paper, a convenient one-pot process for preparing various phenylpropanoid esters from substituted benzaldehydes bearing hydroxyl and/or methoxyl groups has been developed. The alcohols react first with malonic acid catalyzed by boric acid to form monomalonate, then without separation, let the resultant mixture immediately react with the injected various substituted benzaldehydes in the presence of piperidine to afford the desired esters with moderate to good yields. Springer Science+Business Media B.V. 2011.
A catalytic asymmetric synthesis of chiral glycidic acid derivatives through chiral dioxirane-mediated catalytic asymmetric epoxidation of cinnamic acid derivatives
Imashiro, Ritsuo,Seki, Masahiko
, p. 4216 - 4226 (2007/10/03)
A novel and practical asymmetric synthesis of chiral glycidic acid derivatives involving methyl (2R,3S)-3-(4-methoxyphenyl)glycidate ((2R,3S)-2a), a key intermediate for diltiazem hydrochloride (1), was developed. Treatment of methyl (E)-4-methoxycinnamate ((E)-3a) with chiral dioxirane, generated in situ from a catalytic amount (5 mol %) of an 11-membered C2-symmetric binaphthyl ketone (R)-7a, provided (2R,3S)-2a in 92% yield and 80% ee. Other cinnamic acid esters and amides were epoxidized by the use of the same procedure to give the corresponding chiral glycidic acid derivatives with up to 95% yield and 92% ee. Higher enantioselectivities in the asymmetric epoxidation of (E)-cinnamates than that of (E)-stilbene derivatives were observed and were proposed to be attributed to a dipole-dipole repulsion between oxygen atoms of an ester group in the cinnamates and those of the lactone moieties in the binaphthyl dioxirane.
Enantioselective Catalytic Epoxidation of Cinnamate Esters
Jacobsen, Eric N.,Deng, Li,Furukawa, Yoshiro,Martinez, Luis E.
, p. 4323 - 4334 (2007/10/02)
A broad study of the (salen)Mn(III)-catalyzed asymmetric epoxidation of cis-cinnamate esters reveals that the steric properties of the ester group have a profound influence on enantioselectivity in the epoxidation reaction, with bulkier esters affording highest ee's.The sensitivity of the reaction selectivity to the steric properties of the cis-alkene are consistent with a "skewed" side-on approach of olefin to the metal -oxo.The electronic properties of the substrate arene ring substituents do not correlate with epoxidation ee, but instead with the cis/trans partitioning of product formation.Evidence is provided for a non-polar inter mediate in a stepwise oxygen-atom-transfer mechanism.The presence of pyridine N-oxide derivatives has a significant effect on catalysts rates and total turnovers, but negligible influence on the stereoselectivity of epoxidation.A mechanistic basis for the role of these additives is proposed.The synthetic applicability of the cinnamate epoxidation methodology is illustrated in the highly enantioslective synthesis of diltiazem.
