D-2-Hydroxypropanoic acid

Hydroxypropanoic acid, MeCH(0H)C02H, usually known as lactic acid, is a naturally occurring compound present in many foodstuffs. It is chiral and consequently can be found in two enantiomeric forms (Figure 1). The isomer usually called L-(+)-lactic acid has the (5) absolute configuration and D-(—)-lactic acid has the (it) absolute configuration. 

D-Lactic Acid, (R -2-Hydroxypropanoic acid d( —)-lactic acid levorOtatory lactic acid f-lactic acid D-Milchsiiure (German). C3HtO, mol wt 90,08. C 40,00%, H 6.71%, O 53,29%. Obtained by resolution of DL-lactic acid Purdie, Walker, J, Chem. Soc. 61, 754 (1892) Borsook et at. J. Biol. Chem. 102, 449 (1933). Convenient laboratory prepn from glucose using Lactobacillus leichmannii Brin,... 

AI3-00584 DL-Methyl lactate EINECS 208-930-0 EINECS 218-449-8 HSDB 5687 2-Hydroxypropanoic acid methyl ester Lactic acid, methyl ester Methyl 2-hydroxypropanoate Methyl a-hydroxypropionate ( )-Methyl 2-hydroxypropanoate Methyl lactate ( )-Methyl lactate NSC 406248 Propanoic acid, 2-hydroxy-, methyl ester. Colorless liquid bp = 144-145 d = 1.09 soluble in EtOH, Et20. 

Both enantiomers of lactic acid (2-hydroxypropanoic acid) are natural products and easily obtained by biotechnological methods, so there is no need for their synthesis in the laboratory. Even their esters with alkanols, e.g.. 1, are comparatively inexpensive and, therefore, convenient starting materials for derivatization to chiral reagents and auxiliaries. If necessary, such esters can be obtained by any convenient esterification technique. O-Acylated derivatives of lactic esters have been used very successfully as chiral auxiliaries in diastereoselective Diels-Alder reactions (Section D.1.6.1.1.1.1.2.). The acrylate 2 and methacrylate 31-3 and the fu-marate 43 give very high enantiomeric excesses. These are obtained from the lactic ester by treatment with an acid chloride. 

D-lactic acid (f )-2-hydroxypropanoic acid - F (lithium salt A, F, J, M)... 

Over the past several decades, polylactide - i.e. poly(lactic acid) (PLA) - and its copolymers have attracted significant attention in environmental, biomedical, and pharmaceutical applications as well as alternatives to petro-based polymers [1-18], Plant-derived carbohydrates such as glucose, which is derived from corn, are most frequently used as raw materials of PLA. Among their applications as alternatives to petro-based polymers, packaging applications are the primary ones. Poly(lactic acid)s can be synthesized either by direct polycondensation of lactic acid (lUPAC name 2-hydroxypropanoic acid) or by ring-opening polymerization (ROP) of lactide (LA) (lUPAC name 3,6-dimethyl-l,4-dioxane-2,5-dione). Lactic acid is optically active and has two enantiomeric forms, that is, L- and D- (S- and R-). Lactide is a cyclic dimer of lactic acid that has three possible stereoisomers (i) L-lactide (LLA), which is composed of two L-lactic acids, (ii) D-lactide (DLA), which is composed of two D-lactic acids, and (iii) meso-lactide (MLA), which is composed of an L-lactic acid and a D-lactic acid. Due to the two enantiomeric forms of lactic acids, their homopolymers are stereoisomeric and their crystallizability, physical properties, and processability depend on their tacticity, optical purity, and molecular weight the latter two are dominant factors. 

Lactic acid (2-hydroxypropanoic acid) is the simplest 2-hydro)ycarbo)ylic acid with a chiral carbon atom and exists in two optically active stereoisomers, namely l and d enantiomers S and R in absolute configuration, respectively), as shown in Scheme 1.1. These l- and u-lactic acids are generally synthesized by fermentation using suitable micro-organisms. Racemic DL-lactic acid RS configuration) consisting of the equimolar mixture of D- and L-lactic acids shows characteristics different from those of the... 

Lactic acid, which is also known as 2-hydroxypropanoic acid, is a widely available organic acid in nature. It exists in two enantiomeric (L- and D-) forms and is the modest form... 

Lactic acid (LA 2-hydroxypropanoic acid) is an organic acid and the simplest hydroxycarboxylic acid. It is soluble in water and exists in two enantiomeric forms l-(+)-LA and d-( )-LA. Even though both forms are used in industry, l-LA is the preferred isomer for medical applications because only this form is suitable to be assimilated by the human body. A qualifying feature of this component is its bifunctional reactivity imparted by its carboxyl and hydroxyl groups, which makes it ideal for step-growth polymerization (polycondensation). The annual production of LA is... 

D-Erythrose has also been exposed to a boiling solution in pH 4.5 buffer. Low yields (<0.2%) of a number of products were obtained, as shown in Scheme 3. These included 5-(hydroxymethyl)-2-furaldehyde (11), 2-acetyl-5-(hydroxymethyl)furan (12), 3,4-dihydroxyacetophenone (13), 3,4-dihydroxy be nzaldehyde (14), 3,4-dihydroxybenzoic acid (15), 2,3-dihydroxytoluene (16), and 1,2-benzenediol (pyrocatechol) (17). Also detected were formic, hydroxyacetic, and 3-hydroxypropanoic acids. Pyrocatechol seems to be a product formed from all carbohydrates boiled in aqueous solutions at pH 4-10 it may constitute a statistical product arising from retro-aldol and re-aldol reactions. It has been shown that the aldol reaction may operate at a pH as low as 4. An aldol reaction... 

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