L-2-Amino-3-hydroxybutyric Acid

L-Threonine L-2-Amino-3-hydroxybutyric Acid CH3CHCCOOH HOH NH2 C4H9NO3 Formula wt 119.12... 

ALDC Activity, 110 Aldehyde C-7, 76 Allura Red AC, 27 Allyl Isothiocyanate, 64 Allyl Phenoxy Acetate, 64, 95 Allyl Propionate, 66, 95 L-2-Amino-5-guanidinovaleric Acid, 5 L-2-Amino-3-hydroxybutyric Acid, 60 DL-2-Amino-3-hydroxypropanoic Acid, 50... 

L-2-Amino-5-guanidinovaleric Acid Monohydrochloride, 33 L-2-Amino-3-hydroxybutyric Acid, 413,... 

Amino-3-hydroxybutyric acid a-Amino-P-hydroxybutyric acid L-2-Amino-3-hydroxybutyric acid. See L-Threonine 6-Ami no-4-hydroxy-5-((a,a,a-trifluoro-o-tolyl) azo)-2-naphthalenesulfonic acid, monosodium salt. See Acid red 337... 

L-Homoserine (2-amino-4-hydroxybutyric acid) [672-15-1] M 119.1, m 203", [cc]d +18.3" (in 2M HCI), pKEst(i) -2.1, pl st(2) 3. Likely impurities are A -chloroacetyl-L-homoserine, N-chloroacetyl-D-homoserine, L-homoserine, homoserine lactone, homoserine anhydride (formed in strong solns of homoserine if slightly acidic). Cyclises to the lactone in strongly acidic soln. Crystd from water by adding 9 volumes of EtOH. 

Methyliminodiacetate and glycinate 01 tryptophan ( + )-,( — )-,or ( )-1,2-Diaminocyclopentanetetra-acetate DL-2-Amino-4-hydroxybutyric acid NiV -Ethylenediamine bis-(a-glutaric acid) ds,cis-l,3,5-Triaminocyclohexane-NN N"-triacetate iV-jff-Hydroxyethylpropylenediamine... 

L-(-)-y-benzyloxycarbonylamino-a-ydroxybutyric acid L-(-)-y-amino-a-hydroxybutyric acid (7.4 g, 0.062 mole) was added to 50 ml of aqueous sodium 3 hydroxide solution (5.2 g, 0.13 mole). To the solution was added dropwise 11.7 g (0.068 mole) of carbobenzoxy chloride with stirring at 0°C to 5°C for one hour. The reaction mixture was washed with 50 ml of ether, adjusted to pH 2 with dilute hydrochloric acid, and extracted with four 80-ml portions of ether. The extracts were combined, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, and filtered. The filtrate was evaporated in vacuum, and the residue was crystallized from benzene to give 11.6 g (74%) of 4 colorless plates. M.P 78.5°-79.5°C. 

Synthetic applications of AD which have already appeared and which are of potential industrial interest include the synthesis of propranolol (9) [48], diltiazem (10) [49], carnitine, and 4-amino-3-hydroxybutyric acid (11) [50], azole anti-fungals (12) [51], chloramphenicol (13) [52], reticuline intermediates (14) [53], camptothecin analogs (15) [54], khellactone (16) derivatives [55], taxol C-13 side chain (17) [56], halosarin [64], dehydro- xo-brevicomin [65], and antimalar-ial active cyclopenteno-l,2,4-trioxanes [57], as summarized in Figure 4. 

A soln. of N-tosyl-L-methionine in a mixture of methyl iodide, acetic acid, and 8Q% formic acid allowed to stand 10 hrs. at room temp, in the dark, coned, below 40° under reduced pressure, the resulting oil triturated with dry ether, dissolved in N NaOH-soln., stirred and heated 3 hrs. at 90°, while the pH is kept at 6-7 by addition of more N NaOH, and the intermediate N-tosyl-a-amino-7-hydroxybutyric acid treated with N HCl at pH 2-3 -> N-tosyl-a-amino-y-butyro-lactone. Y 92%. F. e. s. H. Sugano and M. Miyoshi, Bull. Chem. Soc. Japan 46, 669 (1973). 

Two reports appeared simultaneously in 1988 describing the electrophilic animation with DTBAD of P-hydroxybutyrate and its l,3-dioxan-4-one protected form [22] and of various P-hydroxy esters [23]. The authors obtained similar results. P-Hydroxy esters 46 or 48 were deprotonated at the a-carbon with LDA (2 equiv.) in THF at low temperature and the resulting enolates reacted rapidly with DTBAD at -78 °C to give an easily separable mixture of syn and anti adducts 47 or 49 in which the anti diastereomer was the major compound. The adducts are very useful intermediates since compounds with anti stereochemistry are not easily accessible by other established methods for a-amino P-hydroxy acids synthesis (Schemes 24 and 25). 

Asymmetric synthesis of fi-lactams The [2+2]cycloaddition of benzyloxyketencs and imincs 2 derived from (R)-l results in. l -riy-disubstituted /8-lactams (3), which can be converted to optically active 3-amino-2-hydroxybutyric acids (5). 

Mild hydrolysis of butirosin A and B with acid slowly liberated n-xylose and n-ribose, respectively. Hydrolysis with concentrated acid gave neamine, neosamine C, 2-deoxystreptamine, and a novel amino acid, 4-amino-3,4-dideoxy-L-gtycero-tetronic acid [(S)-( —)-4-amino-2-hydroxybutyric acid] (53). Treatment of the methyl ester of this amino... 

The following substrates were used to assess blood-brain barrier transport systems L-lysine and L-histidine (basic and neutral amino acid systems, respectively), adenine (purine base), thiamine (vitamin), choline (amine), pyruvate (monocarboxylic acid) and 3-hydroxybutyrate (ketone body). Tracer levels of the C-labelled substrates (Amersham International pic) were added to the perfusate at 0.3-1.2 /iCi/ml together with pH]inulin at l.OjUCi/ml as intravascular marker. Following a net perfusion time of 18.5 s, the animal was decapitated. The brain was rapidly removed, sliced into 2 mm coronal sections and quick-frozen on solid CO2. Each slice was dissected on a freezing... 

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