A Synthesis of dl-Threonine

Adkins, Homer; Reeve, E. Wilkins

doi:10.1021/ja01273a015

Cited by 46 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Ligand Synthesis: Dimethyl 2‐(hydroxyimino)malonate (dmm‐NOH) was obtained by the reaction of dimethyl malonate with sodium nitrite in acetic acid 38. The crude liquid product contained some unreacted dimethyl malonate and was purified by fractional microdistillation (bp.…”

Section: Methodsmentioning

confidence: 99%

Dimethylmalonato Zinc Complexes as Molecular Precursors for Electronic Grade Zinc Oxide: Towards a Systematic Ligand Design by Understanding Molecular Decomposition Mechanisms

Hoffmann

Schneider

2014

Eur J Inorg Chem

View full text Add to dashboard Cite

Zinc complexes with dimethyl 2-hydroxyimino-and 2-nitromalonate (dmm-NOH and Hdmm-NO 2 , respectively) were synthesized and examined as potential precursors for nanocrystalline zinc oxide. The functionalised 1,3-diketones are sufficiently acidic to allow direct synthesis from hydrozincite or zinc 2-propoxide as well as their full spectroscopic and analytical characterization. Their nominal elemental compositions of [Zn 4 O(dmm-NO) 6 ] and [Zn 3 (OH) 4 (dmm-NO 2 ) 2 ] suggest the presence of multinuclear cage structures with oxo-or hydroxo-bridging ligands. This assumption is in ac-

show abstract

Section: Methodsmentioning

confidence: 99%

Dimethylmalonato Zinc Complexes as Molecular Precursors for Electronic Grade Zinc Oxide: Towards a Systematic Ligand Design by Understanding Molecular Decomposition Mechanisms

Hoffmann

Schneider

2014

Eur J Inorg Chem

View full text Add to dashboard Cite

show abstract

“…For related structures, see: Ramos Silva et al (2004); Forsyth et al (2006). For the synthesis, see: Adkins & Reeve (1938). Symmetry codes: (i) Àx þ 1 2 ; y þ 1 2 ; Àz þ 1 2 ; (ii) Àx þ 1; Ày; Àz þ 2; (iii) x À 1 2 ; y À 1 2 ; z À 1.…”

Section: Related Literatureunclassified

“…The title compound, (I), was prepared following a modified literature method (Adkins and Reeve, 1938). A solution of sodium nitrite (5 mmol) and water (2 ml) was added drop-wise to a solution of ethyl 3-oxo-3-(4-nitrophenyl)propanoate (2 mmol) in glacial acetic acid (3 ml) at 273 K. The resulting solution was stirred for 1 h at 273 K. The temperature was then raised to 303 K and the reaction left for a further hour.…”

Section: S2 Experimentalmentioning

confidence: 99%

(Z)-Ethyl 2-hydroxyimino-2-(4-nitrobenzyl)ethanoate

et al. 2009

View full text Add to dashboard Cite

The title molecule, C11H10N2O6, has a Z conformation about the C=N bond of the oxime unit. There are significant twists from planarity throughout the molecule, the most significant being between the hydroxyimino and ester groups which are effectively orthogonal with an N—C—C—Ocarbonyl torsion angle of 91.4 (2)°. The crystal packing features oxime–benzoyl O—H⋯O contacts that lead to chains along [010] and C—H⋯O interactions also occur.

show abstract

“…The stereochemical complexity of threonine renders stereoselective organic synthesis of d-threonine impracticable for an industrial scale-up due to low conversion and/or coproduction of stereochemical impurities [9][10][11]. In contrast, organic synthesis of dl-threonine with a negligible level of diastereomeric impurities has been well established [12][13][14]. This has spurred development of chiral resolution of dl-threonine by preferential crystallization, which requires several successive crystallizations to achieve a high enantiopurity [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Preparation of d -threonine by biocatalytic kinetic resolution

Han

Shin

2015

Journal of Molecular Catalysis B: Enzymatic

View full text Add to dashboard Cite

d-Threonine is one of the important unnatural amino acids used as chiral building blocks in pharmaceutical drugs. Owing to the presence of two chiral centers, a synthetic protocol, either through chemocatalysis or biocatalysis, has not yet been available for one-step preparation of stereochemically pure d-threonine in terms of enantiomeric and diastereomeric excesses (i.e., both >99%). Here we demonstrate that facile production of d-threonine can be implemented using threonine deaminase (TD) via kinetic resolution of dl-threonine that can be readily prepared by conventional organic synthesis. TD catalyzes the dehydration/deamination of l-threonine, leading to generation of 2-oxobutyrate and ammonia. In contrast to mild substrate inhibition of the TD activity by l-threonine (i.e., apparent inhibition constant (K app I ) = 950 mM), d-threonine turned out to be a strong inhibitor (i.e., K app I = 41 mM). In addition to the enzyme inhibitions by both enantiomers of threonine, cell lysis observed during small-scale kinetic resolutions of ≥1 M dl-threonine led us to carry out a preparative-scale reaction at 500 mM racemic substrate. The preparative-scale kinetic resolution in a 50 mL reaction mixture charged with 3 g dl-threonine and 3400 U whole cells was completed at 5 h with >99% ee of d-threonine. Product isolation by a cation-exchange chromatography led to white solid of d-threonine (1.36 g, 90.7% isolation yield). To explore whether our strategy could afford coproduction of another valuable unnatural amino acid, the pass-through solution from the cation-exchange column was further processed by a -transaminase (-TA) reaction where 2-oxobutyrate was converted to enantiopure homoalanine using isopropylamine as an amino donor. Addition of S-and R-selective -TA to the pass-through solution led to 93.2 and 90.9% reaction yield within 12 h with both >99% ee of the produced l-and d-homoalanine, respectively.

show abstract

A Synthesis of dl-Threonine

Cited by 46 publications

References 0 publications

Dimethylmalonato Zinc Complexes as Molecular Precursors for Electronic Grade Zinc Oxide: Towards a Systematic Ligand Design by Understanding Molecular Decomposition Mechanisms

Dimethylmalonato Zinc Complexes as Molecular Precursors for Electronic Grade Zinc Oxide: Towards a Systematic Ligand Design by Understanding Molecular Decomposition Mechanisms

(Z)-Ethyl 2-hydroxyimino-2-(4-nitrobenzyl)ethanoate

Preparation of d -threonine by biocatalytic kinetic resolution

Contact Info

Product

Resources

About