D -tryptophan

CN 6-D-tryptophan-9-(Af-ethyl-L-prolinamide)-10-deglycinamide luteinizing hormone-releasing factor (pig)... 

Satel S., Krystal J., Delgado R, Kosten T., Chamey D. Tryptophan depletion and attenuation of cue-induced craving for cocaine. Am. J. Psychiatry. 152 778, 1995. 

True fruit flavorings, 22 571 True Heat process, 20 50 True moving-bed countercurrent adsorption system, 2 681 Truncated inverted pyramid (TIP) die, 24 847. See also TIP LED Trypan red, 3 2 D-Tryptophan... 

Polyakova, Y. and Row, K. H., Retention behaviour of N-CBZ-D-phenylalanine and D-tryptophan Effect of ionic liquid as mobile-phase modifier, Acta Chromatogr., 17, 210-221,2006. 

Despite the known propensity for racemization, base-catalyzed cyclization continues to be used occasionally. Thus a series of cyclodipeptides derived from 1-methyl-L- and D-tryptophans and S-methyl-L-and D-cysteine have been prepared by ammonia-catalyzed cyclization (87JMC1706), (Scheme 1). 

Tadalafil (3, IC-351) was discovered at ICOS and is being developed and marketed as a joint venture with Eli Lilly, D-tryptophan methyl ester (21) was condensed with piperonal by means of trifluoroacetic acid and the C2 carbon of the indole adds to the resulting iminium ion to give a mixture of cis (3-carboline 22 and trans isomer 23 (Scheme 5). The desired cis isomer 22 can be isolated by chromatography or crystallization in 42% yield. Compound 22 was acylated with chloroacetyl chloride to... 

An alternate step-wise cyclization strategy to form 3-carboline 22 is shown in Scheme 7. Acylation of D-tryptophan (21) with piperonyloyl chloride afforded amide 25, which was converted to thioamide 26 with Lawesson s reagent. Thioamide 26 was treated with methyl iodide in refluxing CH2CI2 to give a a-thiomethylimmonium ion, which was trapped by the intramolecular addition of indole. The thiomethyl group was... 

Hydroxy-L-tryptophan [4350-09-8] M 220.2, m 273 (dec), [a] -32.5 , [a] 5 -73.5 (c 1, H2O). Likely impurities are 5-hydroxy-D-tryptophan and 5-benzyloxytryptophan. Crystd under nitrogen from water by adding EtOH. Stored under nitrogen. 

Eq. 18-38).206 The enzyme is induced both by glucocorticoids and by tryptophan.207 The related indola-mine 2,3-dioxygenase catalyzes the same reaction of L-tryptophan but also acts on D-tryptophan and other substrates. It has different tissue distribution and reg- ulatory properties208 and may play a role in... 

Purification of a-chy-motrypsin by affinity chromatography on immobilized D-tryptophan methyl ester. From Affinity Chromatography Principles and Methods, Pharmacia, Uppsala, Sweden. 

Streptonigrin.—Details of a study of the biosynthesis of streptonigrin (139) that had earlier been published in preliminary form (cf. Vol. 9, p. 24 Vol. 10, p. 23) are now available in full papers.51 52 In essence, the new results are that labelled anthranilic acid was not incorporated into streptonigrin (139),51 that l-rather than D-tryptophan was a precursor, and that label from C-7a in tryptophan (94) appeared, it was deduced, at C-8 in (139).52 The exclusive labelling of C-8 by tryptophan indicates that rings A and B do not derive from this amino-acid. These rings do not derive from phenylalanine and tyrosine, and negative results have been obtained with shikimic acid due, at the least, to poor cellular uptake.51... 

It is well known that the incorporation or substitution of a D-tryptophan residue into a biologically active peptide chain enhances the activity of that chain. Furthermore, such incorporation or substitution will prolong the biological activity. The prolonged and enhanced effectiveness of such peptides probably relates the increased resistance to degradation by peptidases. 

An expeditious enantioselective synthesis ofn-methyltryptophan was accomplished using the Seebach oxazolidinone procedure. The oxazolidinone 36b was prepared from D-tryptophan and pivalaldehyde. Alkylation was carried out without indoIe-A -protection using 2.2 equiv. of LDA and 1.2 equiv. of methyl iodide. Under these conditions, ( -alkylation ocurred preferentially. R-d-methyltryptophan was obtained by hydrolysis of 36c. <95JOC5719>... 

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