D(-)-allo-Threonine is an isomer of threonine. It is found as a constituent of an increasing group of biologically active peptides. Stereocontrolled syntheses of chiral and racemic key intermediates to thienamycin can be achieved from d-allo-threonine and trans-crotonic acid.
https://www.alfa.com/en/catalog/H27050/
http://www.sigmaaldrich.com/catalog/product/sigma/t9643?lang=en®ion=US
They are found as constituents of an increasing group of biologically active peptides. Stereocontrolled syntheses of chiral and racemic key intermediates to thienamycin from d-allo-threonine and trans-crotonic acid.
ChEBI: D-allothreonine is the D-enantiomer of allothreonine. It occurs as a component of peptido-lipids in certain bacteria. It has a role as a bacterial metabolite. It is an allothreonine and a D-alpha-amino acid. It is an enantiomer of a L-allothreonine. It is a tautomer of a D-allothreonine zwitterion.
The general procedure for the synthesis of L-threonine from 5-(1-hydroxyethyl)urea (CAS:64420-00-4) is as follows: in a 1 L autoclave, 144 g (1 mol) of 5-(1-hydroxyethyl)urea, 68 g of 25% ammonia solution, 110 g of calcium hydroxide (1.5 mol), 500 g of deionized water and 50 mL of n-butanol were added in sequence. The reaction mixture was heated to 160-170°C and the reaction pressure was maintained at 1.5-2.0 MPa for 4 hours. After completion of the reaction, the reaction was cooled to room temperature, and carbon dioxide gas was introduced to adjust the pH of the reaction solution to 8. The insoluble material was removed by filtration, and the mother liquor was concentrated under reduced pressure. To the concentrated residue, 150 g of methanol was added and refluxed for 2 hours, then cooled to room temperature and crystals were precipitated. The crystals were collected by filtration, and the filter cake was dried under vacuum at 120°C for 4 h. 106.4 g of 2-amino-3-hydroxybutyric acid (L-threonine) was obtained with a purity of 96% and a yield of 89.4%.
Recrystallise D-allothreonine from aqueous EtOH or 50% EtOH. [Elliot J Chem Soc 62 1950, Birnbaum et al. J Biol Chem 194 455 1952, IR: Greenstein & Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 1961, Beilstein 4 IV 3170.]
[1] Patent: CN104892521, 2018, B. Location in patent: Paragraph 0069; 0070
