L-lysine ethyl ester

In the course of several studies devoted to the syntheses of unusual isocyanates, we developed an improved process for the preparation of the already known ethyl-2,6-diisocyanato hexanoate by phogenation of L-Lysine ethyl ester as depicted in scheme 125 (Ref. 178). 

Scheme 125 Phosgenation of L-Lysine ethyl ester to the corresponding isocyanate.

Starting material, dried Decolored protein hydrolysate L-Lysine ethyl ester 2HC1 L-Methionine ethyl ester HC1 L-Tryptophan ethyl ester HC1 Plastein... 

L-lysine methyl ester HC1 L-lysine ethyl ester HC1 Polyurea H — Me Mn 5,900 Polyurea R — Et Mn 17,000... 

Gemini gelators (e.g., N-lauroyl-L-lysine ethyl ester) Boc-Ala(l)-Aib(2)-P-Ala(3)-OMe (synthetic tripeptide) ... 

Qin X, et al. (2011) Protease-Catalyzed Oligomerization of L-Lysine Ethyl Ester in Aqueous Solution. ACS Catalysis. 1 p. 1022-1034. 

Through urethane bond hydrolysis, LDI-based PURs release L-lysine ethyl ester, a non-toxic degradation product, as a result of LDI reaction with water (Skaija et al.,... 

In a similar approach, our group synthesised two biodegradable poly(ester urethane)s from PCL macrodiol and 1,4-diisocyanatobutane (SUvestti et al., 2014). The PURs differed in the chain extenders, which were L-lysine ethyl ester and AAK. The PUR containing the peptide sequence showed a higher weight loss in elastase solution. 

PCL diol, BDI, and L-lysine ethyl ester dihydrochloride 3D porous scaffolds fabricated by melt-extrusion additive manufacturing and thermally induced phase separation Chiono et al. (2013a) Boffito et al. (2015)... 

To achieve biodegradability and nontoxicity, there has been intensive research on replacing common isocyanates with amino acid diisocyanates in the development of waterborne PUs [69]. L-Lysine diisocyanate and L-lysine ethyl ester diisocyanate have gained attention because lysine is nontoxic, less prone to inflammation, and easy to connect with bioactive molecules. Lysine ethyl ester diisocyanate was prepared with an improved method that avoids the use of gaseous phosgene, elevated temperature, and strongly acidic conditions as described by Nowick et al. [70]. L-Lysine diisocyanate and PCL diol were used as main components to prepare nontoxic and... 

Zhou et al. described the synthesis of pH-sensitive biodegradable PUs. They used a novel pH-sensitive macrodiol containing acid-cleavable hydrazone linkers, poly(E-caprolactone)-hydrazone-poly(ethylene glycol)-hydiazone- ly(E-caprolactone) diol (PCL-Hyd-PEG-Hyd-PCL). The macrodiol was used with L-lysine ethyl ester diisocyanate (LDI) and L-lysine-derived tripeptide as chain extender [47]. These PUs could self-assemble into micelles in aqneons solutions. Later, the same research group synthesized pH-sensitive polymers nsing 1,4-bntanediol as chain extenders and suggested its use as antitumor drug carriers [41]. 

Han et al. synthesized a SPEsUU from PCL, L-lysine ethyl ester diisocyanate (LDl), and L-lysine ethyl ester (LEE) as chain extender [92], The mechanical properties of the electrospun tubular scaffolds increased with solution concentration, as the fiber diameter was progressively increased. The values of suture-retention strength were higher than those of native blood vessels, whereas the burst pressure strength was slightly lower. No compliance data were reported. The scaffolds displayed no cytotoxicity against L-929 mouse fibroblasts or HUVECs, and in vitro cell attachment proved to be successful. 

Typical procedure. Ethyl 2,6-diisocyanatohexanoate [258] A dry 1000 mL threenecked, round-bottomed flask equipped with a mechanical stirrer was charged with purified N,N -bis(trimethylsilyl)-L-lysine ethyl ester (50 mL), anhydrous diethyl ether (400 mL), and triethylamine (39 mL). The mixture was cooled to —20 °C, whereupon a solution of triphosgene (30 g) in anhydrous diethyl ether (200 mL) was added dropwise over a period of 30 min. The reaction mixture was kept at 20 °C for 4 h, and then the flask was removed from the cold bath and reaction was allowed to proceed at room temperature for an additional 36 h. Triethylamine hydrochloride was removed by vacuum filtration and the diethyl ether was evaporated in vacuo to yield the crude ethyl 2,6-diisocyanatohexanoate. The product was purified by vacuum distillation and approximately 15 mL of the fraction that distilled in the range 120-132 °C at 0.1 mmHg was collected. 

Polyurea membranes have been produced in the reaction between L-Lysine ethyl ester dihydrochloride with 1,4-phenylene diisocyanate, followed by dissolving the polymer in DMAc/LiCl (5%) and obtaining the membrane by evaporation of the solvent [56]. By the addition to the membrane synthesis mixture of N-a membrane-benzyloxycarbonyl-D-glutamic acid (ZD-Glu) or N-a-benzyloxycarbonyl-L-glutamic acid (ZL-Glu), and extraction of these imprint molecules using a solution of ethanol in water, a molecularly imprinted membrane is obtained, which has an affinity for Z-D-Glu or Z-L Glu. The material thus obtained was used for enantioselective electrodialysis, the imprinted molecule being retained in the membrane, and transport being allowed only for the other enantiomer. 

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