Trimethylpyruvic acid

Figure 4.18 Enzyme membrane reactor synthesis of L-tert-leucine from trimethylpyruvic acid in an continuously operated enzyme membrane reactor with ultrafiltration followed by a crystallization step...

Because of its bulky, inflexible, and hydrophobic side chain, terf-leucine (2-amino-3,3-dimethylbutanoic acid, Tie) is an important amino acid used as template or catalyst compound in asymmetric synthesis and in peptidic medicinal compounds. L-Tle has attracted much attention as a key component of newly emerged drugs or as building block of ligands, catalysts, and auxiliaries for asymmetric synthesis. It is synthesized in ton-scale by reductive amination of trimethylpyruvic acid by means of LeuDH from Bacillus stearothermophilus with very high yield and excellent optical purity [153]. NADH, which is consumed during the reaction, can be regenerated by FDH from C. boidinii (Fig. 35). 

One of the prominent industrial bioreduction processes, run by cofactor regeneration, is performed by leucine dehydrogenase. This enzyme can catalyze the reductive amination of trimethylpyruvic acid, using ammonia (see Fig. 3.45). For this process the cofactor regeneration takes place by using formate as the reductant and formate dehydrogenase as the second enzyme. The advantage of... 

An oxidizable alkyl group is not necessarily attached to an aromatic nucleus. Oxidation of a methyl group of trimethylacetic acid by heating for 7 hours with alkaline permanganate gives dimethylmaIonic acid (35%). Other examples include the a-keto acids, trimethylpyruvic acid (40%) ° from pinacolone and /3-naphthylglyoxylic acid (40%) from -acetyl-naphthalene. 

Preparative Methods prepared by esterification of f-leucine with Isobutene and cone Sulfuric Acid (under pressure). Typical yields are 62-64% and 12-14% of recovered amino acid, t-Leucine itself is commercially available in racemic and optically pure forms. It can also be prepared by oxidation of pina-colone to trimethylpyruvic acid, followed by oxime formation and zinc reduction. Resolution of the iV-formyl derivative of t-leucine has been carried out using brucine. ... 

AI3-11509 Butanoic acid, 3,3-dimethyl-2-oxo- tert-But-ylglyoxylic acid Butyric acid, 3,3-dimethyl-2-oxo- 3,3-Dimethyl-2-oxobutyric acid 3,3-Dimethyl-2-oxobutan-oic acid EINECS 212-418-2 Glyoxylic acid, tert-butyl- HSDB 5757 NSC 16648 Pyruvic acid, trimethyl- Trimethylpyruvic acid. Crystals mp = 90,5° bp = 189, bpi5 = 80° 4m= 312 nm (e = 30, etOH) slightly soluble in H2O, soluble in Et20, CeHe, CHCI3, CS2. 

Synthesis of (S)-teit-leucine via leucine dehydrogenase-catalyzed reductive amination of trimethylpyruvic acid (TMP or ketopivalic acid)... 

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