Indoles, 2-substituted synthesis

Another indole/oxindole synthesis achieves the critical ortho-substitution by Sommelet-Hauser rearrangement of an anilinosiilfonium ion intermediate. Use of P-thioketones (G = R, an alkyl group) generates 2-substituted indoles, whereas P-thioesters (G = OR) lead to oxindoles. In each case, a 3-thio substituent must be removed by desulfuri2ation. 

Pyrano[3,2-g]benzoxazine, dihydrosynthesis, 3, 714 Pyranobenzoxazines synthesis, 6, 190 Pyranobenzoxazoles mass spectra, 3, 615 Pyrano[2,3-a]carbazoles synthesis, 4, 235 Pyrano[2,3- 6]carbazoles synthesis, 4, 235 Pyrano[3,2-a]carbazoles synthesis, 4, 235 Pyranochromones synthesis, 3, 821 Pyranochromones, dihydrosynthesis, 3, 81 817 Pyranocoumarins crystal data, 3, 623 mass spectra, 3, 610 Pyranodipyranones synthesis, 3, 794 Pyrano[3,2-6]indol-4-ones synthesis, 4, 302 Pyran-2-ol, dihydrodehydration, 3, 762 Pyran-2-ol, 3-methyltetrahydro-synthesis, 3, 775 Pyran-2-ol, tetrahydro-6-substituted synthesis, 3, 775 Pyran-4-ol, tetrahydro-IR spectra, 3, 594 Raman spectra, 3, 594 Pyranols, tetrahydro-bond lengths, 3, 621 synthesis, 3, 777... 

Bosch s group cross-coupled both 2- and 3-indolylzinc derivatives with diversely substituted 2-halopyridines to assemble 2- and 3-(2-pyridyl)indoles, which have become important intermediates in indole alkaloid synthesis [23-28]. Thus, l-(phenylsulfonyl)indole (30) was converted to 2-indolylzinc reagent 32, which was then coupled with 2-halopyridine 33 to secure 2-(2-pyridyl)indole 34. 

The reaction between zinc-copper reagents and acid chlorides is very general and provides a useful synthesis of ketones [7, 34, 41, 42], This acylation has also been used to prepare various indoles substituted in position 2 (Scheme 2.42) [88],... 

This enzyme [EC 4.1.99.1], also known as L-tryptophan indole-lyase, catalyzes the hydrolysis of L-tryptophan to generate indole, pyruvate, and ammonia. The reaction requires pyridoxal phosphate and potassium ions. The enzyme can also catalyze the synthesis of tryptophan from indole and serine as well as catalyze 2,3-elimination and j8-replacement reactions of some indole-substituted tryptophan analogs of L-cysteine, L-serine, and other 3-substituted amino acids. 

Indole, l-methyl-2-sulfonamido-tautomerism, 4, 200 Indole, l-methyl-3-sulfonamido-tautomerism, 4, 200 Indole, (methylthio)-synthesis, 4, 368 Indole, 3-(methylthio)-synthesis, 4, 338, 368 Indole, l-methyl-3-vinyl-oxidation, 4, 280 Indole, nitro-rearrangement, 4, 297 Indole, 3-nitro-nitration, 4, 211, 213 reduction, 4, 362 synthesis, 4, 210, 363 Indole, 5-nitro-synthesis, 4, 211, 363 Indole, nitroso-rearrangement, 4, 297 Indole, 1-nitroso-reduction, 4, 362 Indole, 3-nitroso-reduction, 4, 362 Indole, nitrovinyl-cycloaddition reactions, 4, 284 Indole, 3-(2-nitrovinyl)-nucleophilic addition reactions, 4, 281 Indole, perhydro-structure, 4, 196 Indole, 2-phenyl-metabolism, 1, 228 3-substituted ipso substitution, 4, 212 synthesis, 4, 126 Indole, 3-phenyl-... 

In an attempt to synthesize a component 50 of exochelin MN (51), the regioin-versed AA of imidazol acrylates 49 under the influence of the (DHQD)2AQN ligand was investigated (Scheme 9). While hydroxyphenyl-substituted substrates such as 48a and 48b gave satisfactory yields (45-55%), regioselectivities (3 1 — 1 0), and enantioselectivities (84-86% ee), no reaction was observed with imidazole-substituted substrates like 48c [71], However, the synthesis of the indole-substituted amino acid 52, a component of cyclomarin A (53), was achieved in 36% yield (Scheme 9) [72], The diastereoselectivity of the AA reaction was determined to be 95 5. 

Oxazolone itself can be easily obtained from oxazolidinone through electrochemical reduction as described in CHEC-II(1996). A similar sequence was utilized in the synthesis of indole-substituted 2(3//)-oxazolone 244 (Scheme 71) <1997CPB733>. Electrochemical oxidation of 2-oxazolidinone in methanol gave a 4-methoxy oxazolidinone 241, which reacted with an organomagnesium indole reagent 242 in the presence of BF3-Et20, followed by... 

This method (Batcho-Leimgruber synthesis) is particularly suitable for the synthesis of indoles substituted on the benzene ring but unsubstituted on the pyrrole moiety [49]. 

Synthetically attractive indolisation procedures and new methods for the preparation of selectively substituted indoles , Pindur, U. and Adam, R., J. Heterocycl. Chem., 1988, 25, 1 Recent developments in indole ring synthesis - methodology and applications , Gribble, G. W., J. Chem. Soc., Perkin Trans. 1, 2000, and previous reviews in the series. 

Indoles substituted at C-3 with butadienyl or styryl groups undergo electrocyclic reactions to give carbazole derivatives. The silyl enol ether (275) can be converted thermally directly into the carbazole (276), as the result of ready elimination of methanol this sequence is crucial for a hyellazole synthesis (Equation (96)) <89CC43>. Several related 3-styrylindole sequences have been developed and differ with respect to the placement of ethyl carbonate groups on the alkene. Both the substrates (277) and (279) undergo photocyclization to the respective benzocarbazoles (278) and (280) as a result of... 

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