Heteroatom methods

Knowles, Jonathan P.; Whiting, Andrew

doi:10.1039/b927093k

Cited by 3 publications

(2 citation statements)

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“…Alkoxide bases were used as catalysts for the aza-Michael reaction, KOH, NaOH, NaOC(CH 3 ) 3 , KOC(CH 3 ) 3 , NaOCH 3 , KOCH 3 , and CH 3 COONa (as shown in Table 1). [38][39][40][41] The strong bases NaOH and KOH showed less catalytic reactivity, and the trifunctional structure of itaconic acid ensured that the reactivity of carboxylic acid and unsaturated bond differed. The itaconic acid and amino acidbased heterocyclic diacid developed after the reaction of the alkene group of itaconic acid with the amine group of the amino acid.…”

Section: Synthesis Of Chiral Diacidmentioning

confidence: 99%

“…Alcohols are weak acids, while the sodium and potassium salts of alcohol easily dissociate in the reaction solution with alkoxides as conjugate bases. [38][39][40][41] The alkoxides abstract hydrogen from the amino acid after reaction with a nucleophile and directly react with the unsaturated double bond of itaconic acid. This forms a resonant-stabilized intermediate enolate with electronegative oxygen, which was subsequently protonated to form a ketone.…”

Section: Synthesis Of Chiral Diacidmentioning

confidence: 99%

See 1 more Smart Citation

High‐Performance BioNylons from Itaconic and Amino Acids with Pepsin Degradability

Ali

Kaneko

2021

Advanced Sustainable Systems

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dianhydro-d-mannitol (isomannide), and 1,4,3,6-dianhydro-l-iditol (isoidide). [5][6][7][8] However, low T g values of biobased polyamides restrict their application. [3][4][5][6][7][8] On the other hand, considerable progress has been made in the syntheses of enantiomeric d-and l-poly(hexamethylene di-Omethyltartaramide)s {P6DMT(d-/l-)} a pair of stereoregular polyamides is reported. [9][10][11] The (+)-3-carene based chiral polyamides such as poly-3R-caranamide and poly-3S-caranamide have high T g (70-100 °C). [2] Besides, terpenes-based chiral polyamide, which were derived from (R)-(+)-, (S)-(-)limonene, and (-)-β-pinene showed the T g value in the range of 40-42 °C. [2,12,13] Enhancement of interchain interaction based on chirality should be effective on increasing the softening temperature of the polymers. The polyamides have a synergistic effect on chiral interaction and hydrogen bonding between the different moieties. [11,14,15] Recently, we have reported the preparation of polyamides with heterocyclic amide ring such as pyrrolidone to increase the T g , owing to the rigidity and interchain hydrogen bonding. [16][17][18] The pyrrolidone ring was derived from itaconic acid (IA), which is a notable bio-renewable resource that can be mass-produced from Aspergillus terreus via fermentation using glucose. [17][18][19] IA reacted with amine compounds through its corresponding salt monomer to form heterocyclic pyrrolidone by aza-Michael addition of amines to IA's double bond successive ring-closing condensation with a carboxylic acid upon heating. [20,21] N-substituted amide linkage restricts water absorption, which can contribute to reducing the thermal and mechanical properties of the resulting polymer. [22] The pyrrolidone ring-based polyamides showed corrosive behavior in soil and photo-induced solubilization under UV light, which induce hydrolytic ring-opening. [21,23,24] In particular, symmetrical bis(pyrrolidone)-based dicarboxylic acids prepared from itaconic acid are polymerized and yield amorphous and degradable polymers with low T g values that are susceptible to enzymatic depolymerization. [25,26] However, conventional nonchiral polyamides such as nylon 6, nylon 66, and nylon 11 are not degradable whereas polyamides (nylon 4 and its copolymer nylon-4,4 and -5,4), which were derived from γ-aminobutyric acid (GABA) are biodegradable. [27][28][29] The polyamides from symmetrical monomers were studied, but monomers having head-tail asymmetry such as amino acids should be effective on The use of renewable feedstock for polymers has led to poor thermomechanical properties with high production costs. Herein, the production of novel chiral dicarboxylic acids derived from renewable itaconic and amino acids (d-or l-leucine) is reported. In this study, rigid chiral heterocyclic dicarboxylic acid monomers are obtained with high purity from itaconic acid-derived dimethyl itaconate as a starting material. Chirally interactive polyamides are prepared via melt polycondensation of hexamethylenediamine with heterocycl...

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Section: Synthesis Of Chiral Diacidmentioning

confidence: 99%