S-Mandelate

S-( )-Mandelic acid [61-72-3] M 152.2, m 118 , 120-121 . Purified by Soxhlet extraction with benzene (about 6mL/g), allowing the extract to crystallise. Also crystallises from CHCI3. The S-benzylisothiuronium salt has m 169 (166 ) (from H2O). Dry at room temperature under vacuum. 

A solution of 76 g (S)-( + )-mandelic acid in 400 ml methanol and 5 ml acetic acid was reduced over 5% rhodium-on-alumina under 100 psig for 10 h. The catalyst was removed by filtration through Celite, and the methanol was removed in a rotary evaporator. The white, solid residue was dissolved in I 1 of hot diethyl ether and filtered while hot. After reduction of the volume to 400 ml, 250 ml cyclohexane was added. The remainder of the ether was removed, and the cyclohexane solution was stored for several hours in a refrigerator. The white crystals were filtered and dried in vacuo at 40 C the yield of (S)-( + )-hexahydromandelic acid was 71%. 

Knapp, S. Mandell, A.J. and Geyer, M.A. Effects of amphetamines on regional tryptophan hydroxylase aetivity and synaptosomal conversion of tryptophan to 5-hydroxytryptamine in rat brain. J Pharmacol Exp Ther 189 676-689, 1974. 

Figure 8.12 Conversion of benzaldehyde into enantiomerically pure (S)-mandelic acid by the sequential addition of HCN catalyzed by the (.S )-selective oxynitrilase from Manihot esculenta (MeHnL), and subsequent hydrolysis of the resultant (5)-mandelonitrile by the nitrilase from Pseudomonas fluorescens ECB 191 (PfNLase)...

Mateo, C., Chmura, A., Rustler, S. et al. (2006) Synthesis of enantiomerically pure (S)-mandelic acid using an oxynitrilase-nitrilase bienzymatic cascade a nitrilase surprisingly shows nitrile hydratase activity. Tetrahedron Asymmetry, 17, 320-323. 

Fleming AJ, McQueen-Mason S, Mandel T, Kuhleimer C. Induction of leaf pri-mordia by the cell wall protein expansin. Science 1997 276 1415-1417. 

R)-(+)-1,1,2-Triphenyl-1,2-ethanediol is available from methyl3 and ethyl4 (R)-(-)-mandelate by treatment with phenylmagnesium bromide. The synthesis of (R)-(+)-2-hydroxy-1,2,2-triphenylethyl acetate [(R)-HYTRA] has been reported previously by the submitters.5 6 (S)-(-)-2-Hydroxy-1,2,2-triphenylethyl acetate is available according to this procedure starting from the enantiomeric methyl (S)-(+)-mandelate or (S)-(+)-... 

HPLC/API (S)-Phenylalanine (S)-Mandelic acid methyl ester 0.85 376... 

The present reaction was proven to occur even when the microorganism had been grown on peptone as the sole carbon source. These results lead to the conclusion that this enzyme system is produced constitutively. In the case of man-delate-pathway enzymes in Pseudomonas putida, (S)-mandelate dehydrogenase was shown to be produced in the presence of an inducer (mandelic acid or benzoylformic acid) [5]. Thus, the expression of the present oxidizing enzyme of A. bronchisepticus is different from that of R putida. 

Fig. 9. Effect of pH on EDAs of HNi and RNi modihed with (S)-mandelic acid (A) HNi, (O) RNi, ( ) HNiA, ( ) RNiA. Modifying condition 0 C. Reaction conditions MAA (neat), 60 C, 100 kg/cm2.

However, this consideration could not become a conclusive one because another complicating phenomenon was observed, as shown in Fig. 9 (52a). In the modification of HNi with (S)-mandelic acid, MHNi-ls producing (S)- and (R)-MHB were obtained by the modifications at pH 2.4 and pH 5.0, respectively. However, HNi pretreated with glycolic acid [HNiA-1 (GA)] gave only one kind of MHNi-1 which produced (R)-MHB regardless of the modifying pH. 

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