T-leucine

CTT CCT GCA CCG CAG T leucine proline alanine proline glutamine Figure 2.18 Frame shift mutation caused by insertion of one base, G. 

The asymmetric hydrogenation of the phenylhydrazone of methyl-N-(3,3-dimethyl-2-oxobutanoyl)-(S)-valinate (83) was investigated using palladium catalysts105). The absolute configuration of the newly formed t-leucine moiety in (84) was found to be (S). The diastereoselectivity in the hydrogenation step was shown to be as high as 56%. 

The synthesis of ferrocene 9 relied on chemistry introduced by Sammakia, Uemura, and Richards [18]. They had shown that 2-ferrocenyl oxazoline 10 derived from t-leucine could be selectively deprotonated and trapped with electrophiles to afford ortho-functionalized planar-chiral products 11 with excellent diastereoselectivities (Scheme 2.1.2.3). Following this strategy, 9 became accessible in a highly straightforward manner by trapping the lithiated intermediate derived from 10 with benzophenone [10, 11],... 

Reagents poly-t-leucine, urea-hydrogen peroxide, DBU, THF... 

Intermolecular insertion to aryl C—H bonds is possible. The asymmetric intramolecular reaction of the a-diazo compound 354 catalysed by Rh2[(S)-PTTL]4, Rh2[(S)—PTTL]4 = dirhodium tetrakis[N-phthaloyl(S)—t—leucinate], afforded indane... 

FIGURE 27.4 Deracemization of protected forms of te/t-leucine, naproxen, and ibuprofen. 

A method based on the DKR of 4-substituted-2-phenyloxazolin-5-one has been apphed to the large-scale synthesis of N-benzoyl-t-t-leucine-butyl ester 19, an important non-natural amino acid intermediate of several biomimetic peptides. The procedure is based on the alcoholysis of 4-t-butyl-2-phenyloxazoUn-5-one 18 with -butanol catalyzed by the lipase from Mucor miehei (Scheme 13.15) [42]. The unreactive enantiomer is racemized in situ by a base-catalyzed reaction. The... 

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. ... 

In a new synthesis of diltiazem (98b R = Ac, X = CH2CH2NMe2), a calcium antagonist used in the treatment of hypertension, the key step is the diastereoselective reduction of a-ketolactam (97) to the alcohol precursor (98a R = X = H). The reduction of the 1,5-benzothiazepine (97) was achieved using an NaBH4-(5)-amino acid combination (5)-t-leucine was most efficient, and was readily recovered unracemized. 

Fig. 1 Scanning curve of a chromatogram track with 100 ng per chromatogram zone of the amino acids glycine (1), alanine (2), valine (t), leucine (4) ...

Chiral Mannich reaction is als< methylsilyl ether and A-alkylidenecai by (5)-A,)V-phthaloyl-t-leucine chlorK During addition of Et2Zn to. V-sli metric induction is rendered by 55 an aryl group from ArSnMc3 asymmetnc... 

Lanatoside C t-Leucine Levallorphan Levallorphan tartrate Liothyronine... 

A careful screening of metals and of amino acids in the complex showed, that the best results were achieved in the absence of metal salts. The variation in the amino acids revealed that t-leucine is an advantageous residue. The second amino acid and the polymer can be replaced by a simple benzyl group (Tab. 4.3). 

Figure 7.2 Production of unnatural amino acid S-t-leucine from trimethyl pyruvic acid.

Biosynthesis of the branch-chain amino acids, L-isoleucine, L-valine and t- Leucine. TPP = thiamin pyrophosphate. 

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