- First mechanosynthesis of piperlotines A, C, and derivatives through solvent-free Horner–Wadsworth–Emmons reaction
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Piperlotines are natural products characterized by an α,β-unsaturated amide moiety. These compounds found wide applications in Medicinal Chemistry like antibacterials, cytotoxic agents, anticoagulants, among others. To date, diverse methods of synthesis have been reported for piperlotines, but involving the use of catalysts, hazard reagents, anhydrous media or coupling reagents. Thus, in this work, we developed a greener method of synthesis of piperlotines A, C, and derivatives, through mechanochemical activation under solvent-free conditions. The reaction of a β-amidophosphonate, K2CO3, and an aromatic aldehyde afforded target compounds in moderate to good yields (46–77%), in an open atmosphere by grinding. It is worth to mention that this mechanochemical process was under thermodynamic control because just E isomer was isolated for every reaction. Moreover, synthesized piperlotines have been predicted by means of chemoinformatic analysis as potential therapeutic agents for the treatment of arthritis or cancer.
- Ramírez-Marroquín, Oscar Abelardo,Manzano-Pérez, Flavio,López-Torres, Adolfo,Hernández-López, Alejandro,Cortés-Pacheco, Abimelek,Reyes-González, Miguel Angel
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p. 244 - 255
(2019/01/22)
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- A catalytic asymmetric synthesis of chiral glycidic acid derivatives through chiral dioxirane-mediated catalytic asymmetric epoxidation of cinnamic acid derivatives
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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.
- Imashiro, Ritsuo,Seki, Masahiko
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p. 4216 - 4226
(2007/10/03)
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- Highly diastereo- and enantioselective aziridination of α,β-unsaturated amides with diaziridine and mechanistic consideration on its stereochemistry
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During studies of aziridination of α,β-unsaturated amides with diaziridine, we found that we could prepare both the cis- and trans-aziridinecarboxamides by choosing an appropriately substituted diaziridine. While 3-monosubstituted diaziridine 2 was suitab
- Ishihara, Hiroyuki,Hori, Kiyoto,Sugihara, Hiroyasu,Ito, Yoshio N.,Katsuki, Tsutomu
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p. 4272 - 4286
(2007/10/03)
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