N-Acetyl-tryptophan methyl ester

Scheme 21 Pd-catalyzed direct arylation of N-acetyl-tryptophan methyl ester.

The effect of added co-solvent on the initial state is also important in more complicated reactions. For example, in the a-chymotrypsin-catalysed hydrolysis of p-nitrophenyl acetate and of N-acetyl-L-tryptophan methyl ester, the difference in the pattern of rates of hydrolysis when the solvent composition is varied can be attributed to the variation in the properties of the initial states of the esters (Bell et al., 1974). 

The asymmetric dioxygenation of N-acetyl-L(+)- and N-acetyl-D(-)-tryptophan methyl ester (53) with O has been achieved in the... 

Recently, the structure of the first N- and C-protected tryptophan derivative, i.e., N-acetyl-L-tryptophan methyl ester, was solved by Cotrait and Barrans (97). There is one hydrogen bond NH. .. O = C of 2.86 A between the NH indole group and the acetyl C = O of different molecules. Molecular packing in the crystal is established by van der Waals forces between the two hydrophobic methyl groups and the aromatic ring. The conformation of the tryptophanyl side chain is very close to that of the L form of DL-tryptophan formate. Fig. 5 shows bond lengths and angles of N-acetyl-L-tryptophan methyl ester. 

Fig. 5. Bond lengths and angles of N-acetyl-L-tryptophan methyl ester 91)...

Ions monitored in GC-SIM analysis of endogenous and metabolite trytophan and lAA in metabolic studies using 2O. [ N,] indole and [ HjJ tryptophan [112-115]. Tryptophan analysed as its A -acetyl methyl ester [116J and... 

Hydroxyanthranilic add, a product of tryptophan metabolism, is derivatized for gas chromatography as the N-acetyl methyl ester. Methylation with diazomethane first makes the O-methyl methyl ester after evaporation to dryness in a stream of nitrogen, the residue is acetylated in the dark in 50% benzene/acetyl chloride. The solution is again blown dry with nitrogen and dissolved in methanol for chromatography [36]. 

Figure 15 shows the various ring closures of III as an assumed intermediate in the reaction of I with II. Structure IV was expected according to Spande et al. [15], where 3-methyl-indole reacted with 2-hydroxy-5-nitrobenzyl bromide, whereas reaction products of type V were formed when tryptophan [16], tryptophan ethyl ester [17] and N-acetyl-tryptamine [15] were allowed to react with 2-hydroxy-5-nitrobenzyl... 

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