Indolyl-3-propionic acid

Preparation of a-Acety/amino-0-(5-Benzy/oxy-/ndo/yl-3)-Propionic Acid 15 grams a-acetyl-amino-0 -carboxy-/3-(5-benzyloxy-indolyl-3)-propionic acid was suspended in 225 ml water and the suspension refluxed and stirred in a stream of nitrogen until evolution of carbon dioxide ceased (about 2 hours). After cooling somewhat, 120 ml ethyl alcohol was added and the suspension refluxed until the product dissolved. Charcoal was added to the solution the mixture filtered hot, and the filter-cake washed with 50 ml hot 50% aqueous ethanol. 0 -Acetylamlno-/3-(5-benzyloxy-indolyl-3)-propionic acid, MP 164° to 166°C, which crystallized from the filtrate on cooling, was collected, washed with an ice-cold mixture of 15 ml ethanol and 45 ml water, and dried in vacuo over silica gel (yield 11.1 grams, 83%). 

Preparation of a-Acetylamino-a-Carboxy-p-(5-Benzyloxy-Indolyl-3)-Propionic Acid 18 grams ethyl a-acetylamino-a-carbethoxy-p-(5-benzyloxy-indolyl-3)-... 

After cooling in ice to 10°C, the solution was acidified with 24 ml concentrated hydrochloric acid. The solid which separated was filtered off, washed with water (3 x 30 ml) and dried in vacuo over silica gel, to give a-acetylamino-a-carboxy-(5-benzyloxy-indolyl-3)-propionic acid, MP 144° to 146°C (15.0 grams, 95%) sufficiently pure for use in the next stage. 

The proposed mechanism of peptide bond cleavage was checked by isolating the 3-bromo-indolenine (113) (Section III.3.2.) from the model compound 2-(2-nitrophenylsulfenyl)-3-methylindole and the spirolactone (167) from 2-(2-nitrophenylsulfenyl)-indolyl-3-propionic acid, when these compounds were each treated with NBS (371). 

Such a reversible blocking of the 2-position by sulfenylation was of particular interest in the synthesis of bromo-derivatives of indolyl-3-propionic acid. Specific bromination or nitration of the benzene ring of an indole is normally difficult to achieve, since the pyrrole ring also will react with electrophilic reagents. As an example, 5-bromoindole-3-propionic acid has been prepared using this reversible protection, that is by bromination of the 2-sulfenylated compound and removal of the arylthio group by the two consecutive reactions with NBS and NaBKi (727). 

Fabaceae Arachis hypogaea 2-methoxyl-3-(3-indolyl)-propionic acid 2-hydroxyl-3-[3-(l -N-methyl)-indolyl]propionic acid... 

The possible intramolecular acylation of 3-(3-indolyl)propionic acids as a primary step in a route to the ergoline ring system of the ergot alkaloids has received wide attention (80T3123, 81H(16)267). When the 2-position of the indolylpropionic acid is unsubstituted, intramolecular cyclization to that position occurs (57JCS497). The reaction probably involves... 

CAS 54-12-6 EINECS/ELINCS 200-194-9 Synonyms ( )-2-Amino-3-(3-indolyl)propionic acid Tryptophan (INCI) DL-Tryptophan... 

The highly reactive /3-propiolactone displays discriminatory reaction modes toward bases of different softness. For example, the hard alkoxide ion opens the lactone ring via addition to the acyl carbon (82) whereas the soft cyanide (83) and thiolate ions (84) effect displacement at the P carbon. Indole is alkylated at its P position to give 3-( -indolyl)propionic acid (85). 

The reaction of a tryptophan derivative, N- tert-butoxycarbonyl)-L-tryptophan, with hypoxanthine/ xanthine oxidase/Fe(III)-EDTA mainly resulted in the oxygenation of the pyrrole ring of the indole nucleus (Itakura etal. 1994). 2-[(ferf-Butoxy-carbonyl)-amino]-3-(3-indolyl)propionic acid and N- (fer f-butoxycarb onyl) -hT-formylkynurenine were identified as the major products. 

Preparation of (5)-3,3,3-trifluoro-2-hydroxy-2-(5-methyl-3-indolyl)-propionic acid ethyl ester (105, Ri = Me) from 102 (Ri = Me), and 96 via cinchonidine alkaloid catalyst 102 ... 

As a simple indole derivative, the aromatic amino acid tryptophan (2-amino-3-(3-indolyl)-propionic acid) plays an important part in animal and plant metabolism. Its degradation via kynurenine leads, e. g., to formation of nicotinic acid and its amide or of ommochromes which have been found as pigments especially in crustaceans and insects. Observations made on mutant strains of insects and of the mould Neurospora crassa, in which the biosynthetic routes mentioned are blocked, have given a profound insight into the physiology of gene activity [6]. 

Enantioselective Friedel-Crafts alkylation reactions were performed between substituted indoles and methyl trifluoropyruvate, using a chiral nonracemic C2-symmetric 2,2 -bipyridyl copper triflate complex as catalyst. The active copper(II) catalyst was generated in situ. The corresponding 3,3,3-trifluoro-2-hydroxy-2-indolyl-propionic acid methyl esters were formed in good yield (up to 79%), and in up to 90% enantiomeric excess (eq 18). 

Propionic acid, 2-bromo-3-(3-indolyl)-methyl ester rearrangement, 4, 279 Propionic acid, 3-(3,4-dimethyoxyphenyl)-dihydrocoumarin synthesis from, 3, 848 Propionic acid, indolyl-synthesis, 4, 232 Propionic acid, 3-(l-indolyl)-sodium salt pyrolysis, 4, 202 Propionic acid, 3-(3-indolyl)-intramolecular acylation, 4, 220, 221 Propionic acid, 3-phenoxy-chroman-4-one synthesis from, 3, 855 Propionic acid, 3-(3-phenylisoxazoI-5-yl)-bromination, 6, 25... 

For the preparation of 70-72 Koyama etal. (28) employed the 5-3 -(indolyl)-oxazole 88 obtained from ethylindole-3-carboxylate (87) and isocyanomethyl lithium. The oxazole 88 was refluxed in acetic anhydride—acetic acid or propionic anhydride-propionic acid to afford pimprinine (70) and pimprinethine (71) in 13 and 19% yield, respectively. Hydrolysis of these reaction mixtures and that produced with phenylacetic acid anhydride-phenylacetic acid gave high yields (84-92%) of the 3-acylamidoindoles 79-81, which could be smoothly cyclized with phosphorus oxychloride to the natural products 70-72 (28). 

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