3.4- Dihydroxybutyric acid

The acid components required for the synthesis of the ester alkaloids, (+)-trachelanthic and viridifloric acids, were synthesised by stereospecific routes, since the relative stereochemistry of the asymmetric centres in these acids was still uncertain. Eventually they were obtained by appropriate stereospecific icis or trans) hydroxylation of trans-2-isopropylcrotonic acid (34), and its cis-isomer obtained by photochemical isomerisation. After resolution, (+)-trachelanthic acid was identified as the t/irco-2-isopropyl-2,3-dihydroxybutyric acid (35) the corresponding erythro-isomet was identified as viridifloric acid. 

That these two acids are identical has not been established. Macro-tomine gives trachelanthamidine and 2,3-dihydroxybutyric acid (quinine salt, mp 173°-174°, [a] j —104.4°) with sodium hydroxide at 100°C. The same acid forms less readily from heliosupine (149), and a similar structure has been assigned to the acid in the optically inactive cynoglossophine (150). 

Several years ago, we introduced a method for the preparation of optically pure 3,4-dihydroxybutyric acids and their y-lactones based on the alkaline oxidation of 4-linked hexoses (2-4). 

Chiral 3-carbon synthons from optically pure 3,4-dihydroxybutyric acids. 

The general availability of optically pure 3,4-dihydroxybutyric acids has opened up several new routes to chiral 3-carbon fragments with a wealth of functionality. The (S)- and (R)-enantiomers of 3-amino-1,2-dihydroxypropane (15 and 19 respectively) are among the most useful chiral 3-carbon synthons. 

Four-carbon Meta accharinic Acid DL-(3-Deoxytetronic acid), [dl-(2,4-dihydroxybutyric acid)] ... 

Cativiela, C., Diaz-de-Villegas, M. D., Galvez, J. A., Garcia, J. L. Diastereoselective Strecker reaction of D-glyceraldehyde derivatives. A novel route to (2S,3S)- and (2R,3S)-2-amino-3,4-dihydroxybutyric acid. Tetrahedron 1996, 52, 9563-9574. 

Dhamankar, H., Tarasova, Y., Martin, C.H., and Prather, K.L.J. (2014) Engineering E. coli for the biosynthesis of 3-hydroxy-y-butyrolactone (3HBL) and 3,4-dihydroxybutyric acid (3,4-DHBA) as value-added chemicals from glucose as a sole carbon source. Metab. Eng.,... 

See 1 2-Dihydroxybutyric Acid. l-Methylgl3 erol (1 2 3-Trihydroxy-butane)... 

Since the lactone of 2-4-dihydroxybutyric acid 13 is easily available from l-malic acid 16 [27], the authors focussed on exploiting this chiral building block. In the initial phase of the project, they improved the preparation of 13, according to Scheme 3.3, by eliminating TEA in the cyclization of 18-13 (step iii), which represents the major technical burden in large-scale production. The use of the... 

By the action of bromine on nicotine in hydrobromic acid, dibro-motieonine (Formula B), CjQHgOgNgBrj, nodular cr3rstals, m.p. 196 , is obtained. This with zinc dust in warm alkali yields methylamine and pyridyl-jS y-dihydroxybutyric acid,... 

At least 12 new monoterpenes have recently been isolated from saffron, including crocusatins A-L as well as the new (35)-4-dihydroxybutyric acid. °... 

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