Indole-2-carboxylate

Yamazaki, Kondo and coworkers [78] reported on a combination of a Heck reaction and an animation on solid phase for the synthesis of indole carboxylate 6/1-148, employing an acetylated immobilized enamide 6/1-145 and a bifunctionalized... 

Indole-carboxylic acid 2,3-Dihydro-indole EDC Antitumor antibiotic 96 2006JA7136... 

In a process starting with the stereospecific Homer-Wadsworth-Emmons reaction of phosphonoglycinates 99 with 2-iodobenzaldehydes to afford the corresponding (Z)-didehydro-phenylalanine derivatives 100, Brown similarly utilized an intramolecular palladium-catalyzed animation of 100 (Y = 2-chloro-3-pyridyl, Ph, OBn) to form the N-substituted indole carboxylates 101 <00TL1623>. 

Hopkins and Cole had obtained by the oxidation of tryptophane with ferric chloride a body of the composition of C9H7NO this body has been shown by Ellinger to be /8-indole-aldehyde, firstly by oxidising it to /8-indole-carboxylic acid,... 

Pyrrole- and indole-carboxylic acid chlorides react with dialkyl- and diaryl-cadmium to yield the ketones and it is noteworthy that the reaction of the anhydride of indole-2,3-dicarboxylic acid with diphenylcadmium produces 3-benzoylindole-2-carboxylic acid and not its isomer (53JCS1889). The ability of l-methylindole-2-carboxylic acid to react with nucleophiles is enhanced by conversion into the mixed anhydride with methanesulfonic acid. The mixed anhydride reacts with carbanions derived from diethyl malonate and from methyl acetate to yield the indolyl (3- keto esters (80TL1957). 

The acid-base equilibria of 5- and 6-substituted indole carboxylic acids and coumarylic acids can be correlated with om for groups in the 5-position and op for groups in the 6-position,382 confirming the insulating effect of the heteroatom to resonance effects. 

XXXVIII), which on hydrolysis gave the indole carboxylic acid XXXIX. Decarboxylation of XXXIX then gave tryptamine. 

Elsohly, M. A., Jones, A. B., Elsohly, H. N., and Stanford, D. F., Analysis of the major metabolite of delta-9-tetrahydrocannabinol in urine. VI. Specificity of the assay with respect to indole carboxylic acids, /. Anal. Toxicol., 9, 190, 1985. 

The position of the sugar residue in the dihydroindole portion can be determined by methylation of the pigment with diazomethane and subsequent alkaline degradation of the resulting neobetanin derivative. In the case of 5-0-glycosides, 5-hydroxy-6-methoxyindole-2-carboxylic acid is obtained, whereas the 6-O-glyco-sides yield 6-hydroxy-5-methoxyindole-2-carboxylic acid (47,48). The indole carboxylic acids are easily identified by TIjC. 

Catalytic reduction of the nitro-epoxide (8.1, R = COOMe) leads directly to the indole carboxylic ester but when R = H, reduction of the nitro-epoxide does not give the indole. However, cleavage of the epoxide and reduction of the nitro group gives the amine (8.2) which is cyclized by a strong base. 

The bond between the nitrogen and the carbonyl group of A-aryl benzamides possesses sufficient double-bond character that these compounds will also undergo 6-7t electrocyclic closure [88]. The reaction is quite general and occurs for anilides of indole carboxylic acids, as shown in Scheme 44 [89]. The reaction also proceeds if the A-phenyl group is replaced by a pyridine ring [89d] or a vinyl group [90]. 

MeOCH=N Me2, which combines with the deprotonated aromatic. Both tris(piperidin-l-yl)methane and bis(dimethylamino)-r-butoxymethane are said to function even better than the commercially available DMFDMA. A variety of benzene substituents are tolerated and the approach has been utilised for syntheses of, amongst others, 4- and 7-indole-carboxylic esters. 

For a structure-activity relationship study on 5/f-pyrido[4,3-(>]indoles (y-carbolines), we needed both 1-unsubstituted 271 and 1-substituted methyl 2,3-dihydro-3-oxo-5/f-pyrido[4,3-fc]indole -carboxylates 272 (Scheme 42). 

Indole carboxylic acid 187 was converted via a Barton ester to fused indole 194 (11 examples, 5-79% yield). Barton ester 189 was formed by treatment of indole 187 with S-(l-oxido-2-pyridinyl)-l,l,3,3-tetramethyl thiouronium hexafluorophosphate (188, Garner s HOTT reagent) in the absence of light. Upon refluxing in MeCN, the Barton ester 189 decomposes to give nucleophilic ethyl radical 190, which adds to the unsubstituted carbon of alkyne 191 furnishing vinyl radical 192.This species cyclizes onto the C2 position of the indole to provide 193, which aromatizes to dehver the final product 194. The sequence proceeds without the need for an initiator or metal catalyst (14JOC5903). 

A combination of a Mizoroki-Heck reaction and a C—N coupling on solid phase was reported by Yamazaki et al. [105] in the synthesis of indole carboxylate 197 employing immobilized A-acetyldehydroalanine (194) and a bifunctionalized arene 195. In these transformations, 196 is the intermediate. The best results were obtained with o-dibromoarenes such as 195b and 195d using the Pd2(dba)3/P-r-Bu3/Cy2NMe catalytic system developed by Littke and Fu [106]. The protocol was also extended to the synthesis of isoquinolines [107] (Scheme 8.50). 

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