21497-15-4Relevant academic research and scientific papers
Z-Selective phosphine promoted 1,4-reduction of ynoates and propynoic amides in the presence of water
Drikermann, Denis,Kupfer, Stephan,Seifert, Fabian,Steinmetzer, Johannes,Vilotijevic, Ivan,Zi, You
, p. 6092 - 6097 (2021/07/21)
Phosphine-mediated reductions of substituted propynoic esters and amides in the presence of water yield the partially reduced α,β-unsaturated esters and amides with highZ-selectivity. The competitivein situ ZtoE-isomerization of the product in some cases lowers theZtoEratios of the isolated α,β-unsaturated carbonyl products. Reaction time and the amounts of phosphine and water in the reaction mixture are the key experimental factors which control the selectivity by preventing or reducing the rates ofZ- toE-product isomerization. Close reaction monitoring enables isolation of theZ-alkenes with high selectivities. The computational results suggest that the reactions could be highlyZ-selective owing to the stereoselective formation of theE-P-hydroxyphosphorane intermediate.
Synthesis of piplartine analogs and preliminary findings on structure–antimicrobial activity relationship
Fregnan, Antonio Maciel,Brancaglion, Guilherme Andrade,Galv?o, Alexandre Francisco Cerqueira,D’Sousa Costa, Cinara Oliveira,Moreira, Diogo Rodrigo Magalh?es,Soares, Milena Botelho Pereira,Bezerra, Daniel Pereira,Silva, Naiara Chaves,de Souza Morais, Stella Maria,Oliver, Josidel Concei??o,Dias, Amanda Latercia Tranches,Coelho, Luiz Felipe Leomil,Carvalho, Diogo Teixeira,Dias, Danielle Ferreira,de Souza, Thiago Belarmino
, p. 603 - 614 (2017/02/15)
In this work it is described the synthesis, characterization and antimicrobial and toxicity evaluation of a series of analogs of piplartine, a piperamide found in Piper sp. The compounds structures were confirmed by infrared spectroscopy, 1H, 13C nuclear magnetic resonance, high resolution mass spectroscopy and were evaluated against strains of Candida spp., Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Derivative 24 was almost four-fold more potent (IC50: 48.83 μM) and five-fold less toxic (SI > 3) than piplartine (IC50: 189.2 μM; SI: 0.21) against Candida krusei, as well as two-fold more potent than fluconazole (IC50: 104.48 μM). This compound was also active against Candida tropicalis at 97.67 μM. Benzoyl derivative 17 was three-fold more potent (IC50: 85.2 μM) and more than five-fold less toxic (CC50: 231.71 μM) than piplartine (IC50: 315.33 μM and CC50: 41.14 μM) against Staphylococcus aureus. Given these findings, we have found analogs of piplartine which can be assumed as prototypes for the optimization and the development of new antimicrobial (compounds 24 and 17) agents.
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.
