5678-50-2Relevant academic research and scientific papers
Mechanochemical enzymatic resolution of N-benzylated-β3-amino esters
Pérez-Venegas, Mario,Reyes-Rangel, Gloria,Neri, Adrián,Escalante, Jaime,Juaristi, Eusebio
, p. 1728 - 1734 (2017/09/27)
The use of mechanochemistry to carry out enantioselective reactions has been explored in the last ten years with excellent results. Several chiral organocatalysts and even enzymes have proved to be resistant to milling conditions, which allows for rather efficient enantioselective transformations under ball-milling conditions. The present article reports the first example of a liquid-assisted grinding (LAG) mechanochemical enzymatic resolution of racemic β3-amino esters employing Candida antarctica lipase B (CALB) to afford highly valuable enantioenriched N-benzylated-β3-amino acids in good yields. Furthermore the present protocol is readily scalable.
Efficient resolution of racemic N-benzyl β3-amino acids by iterative liquid-liquid extraction with a chiral (salen)cobalt(iii) complex as enantioselective selector
Dzygiel, Pawel,Monti, Chiara,Piarulli, Umberto,Gennari, Cesare
, p. 3464 - 3471 (2008/09/20)
The efficient (up to 93% ee) resolution of racemic N-benzyl β3-amino acids has been achieved by an iterative (two cycle) liquid-liquid extraction process using a lipophilic chiral (salen)cobalt(iii) complex [CoIII(1)(OAc)]. As a result of the resolution by extraction, one enantiomer of the N-benzyl β3-amino acid predominated in the aqueous phase, while the other enantiomer was driven into the organic phase by complexation to cobalt. The complexed amino acid was then quantitatively released into an aqueous phase, by a reductive (CoIII → Co II) counter-extraction using l-ascorbic acid. The reductive cleavage allowed for the recovery of the cobalt(ii) selector in up to 90% yield (easily re-oxidable to CoIII with air/AcOH). The Royal Society of Chemistry.
Enantioselective conjugate addition of hydroxylamines to pyrazolidinone acrylamides
Sibi, Mukund P.,Liu, Mei
, p. 4181 - 4184 (2007/10/03)
(Matrix Presented) Chiral relay templates provide amplification of selectivity in conjugate addition reactions. Reversal of stereochemistry of the product isoxazolidinones has also been demonstrated by a simple change of the Lewis acid.
A facile synthesis of β-lactams by the cyclization of β-amino acids exploiting 3,3′-(phenylphosphoryl)-bis(1,3-thiazolidine-2-thione)
Nagao, Yoshimitsu,Kumagai, Toshio,Tamai, Satoshi,Matsunaga, Hiroshi,Abe, Takao,Inoue, Yoshinori
, p. 849 - 859 (2007/10/03)
3,3′-(Phenylphosphoryl)-bis(1,3-thiazolidine-2-thione) (5), obtained from phenylphosphonic dichloride (7) and sodium salt of 1,3-thiazolidine-2-thione (6), proved to be useful for intramolecular dehydration of various β-amino acids to give the correspondi
1,3-Dipolar Cycloadditions of Ethoxycarbonyl-nitrile Benzylamine, and Synthesis of β-Amino Acids. Synthesis and Reactions of Ethyl 2-Chloro-2-ethoxyacetate and 2-Chloro-2-ethoxyacetyl Chloride
Bach, Karen K.,El-Seedi, Hesham R.,Jensen, Henrik M.,Nielsen, Helene B.,Thomsen, Ib,Torssell, B. G.
, p. 7543 - 7556 (2007/10/02)
The principles of 1,2-cyano-hydroxylation of olefins were applied to the preparation of 1,2-cyano-amines.The dipole component of this cycloaddition was nitrile imines, which formed pyrazolines with olefins.Ring cleavage was accomplished by thermolysis of 3-carboxypyrazolines, which gave 1,2-cyano-amines and subsequent hydrolysis gave β-amino acids.The synthesis of the title reagents were described.Ethyl 2-chloro-2-ethoxy-acetate gave selectively oximes, hydrazones, nitrones, and phosphonium salts with hydroxylamine, hydrazines, N-substituted hydroxylamines and triphenylphosphine respectively.The phosphonium salt was used in a Wittig reaction with aldehydes to give α-ketoesters.Treatment of the acid chloride with allyl alcohols and subsequently with a monosubstituted hydroxylamine gave the allylic ester nitrone, which underwent intramolecular cyclization.Similarly, intramolecular cyclization were carried out with the allylic ester - nitrile oxime and allylic ester - nitrile imine systems.
