Nitro derivatives of 3-hydroxyquinoline

The nitration of 3-hydroxyquinoline with concentrated nitric acid in sulfuric acid at ?30 to +30°C gives 5-nitro-3-hydroxyquinoline (85–92%) and 7-nitro-3-hydroxyquinoline (7–12%). 4-Nitro-3-hydroxyquinoline is formed in 70% yield by nitration in acetic acid. 4,5-Dinitro-3-hydroxyquinoline is formed by further nitration of 4- and 5-nitro-3-hydroxyquinolines.     

1,3-Diaryl-2,2-dihaloaziridines in nitration and bromination reactions

In the nitration of 3-(4-nitrophenyl)-1-phenyl-2,2-dichloroaziridine in acetic acid, 1-(o- and p-nitrophenyl)-derivatives are formed in a 35:65 ratio. 1,3-Di-phenyl-2,2-dichloroaziridine undergoes opening of the three-membered ring under the same conditions, forming a mixture of o- and p-nitroanilides and 2-nitro-4-chloroanilides of 2-acetoxy (or 2-chloro)-2-phenylacetic acids. The bromination of 3-(4-nitrophenyl)-1-phenyl-2,2-dichloroaziridine in aqueous acetic acid leads to 1-(4-bromophenyl)-3-(4-nitrophenyl)-2,2-dichloroaziridine, while in a mixture of acetic acid and acetic anhydride it leads to the anilide of 2-bromo-2-phenyl-acetic acid and 2-bromo-N-(2,4-dibromophenyl)-1-(4-nitrophenyl)-2,2-dichloro-ethylamine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 912–916, July, 1984.     

Methanolysis and hydrolysis of derivatives of methyl 2,5- and 4,5-dihydrofuran-2-carboxylates

Methyl 2,5-dimethoxy-2,5-dihydrofuran-2-carboxylate is formed in the reaction of HCl-CH₃OH with methyl 5-nitro-2-acetoxy-2,5-, 5-nitro-4-acetoxy-4,5-, and 2,5-diacetoxy-2,5-dihydrofuran-2-carboxylates, whereas methyl 2,5-dioxo-3-pentenoate bis(2,4-dinitrophenylhydrazone) and 4-oxo-2-penten-1,5-dioic acid 2,4-dinitrophenylhydrazone are isolated in the presence of 2,4-dinitrophenylhydrazine. Methyl 5-nitrofuran-2-carboxylate is formed by treatment of methyl 5-nitro-2-acetoxy-2,5-dihydrofuran-2-carboxylate with aqueous solutions of acetic or phosphoric acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1600–1603, December, 1977.     

Synthesis and Oxidation of 1,3-Diamino- and 1-Amino-3-azidoindazoles

The amination of 3-amino- and 3-azidoindazoles by hydroxylamine-O-sulfonic acid in an alkaline medium yields previously unreported 1,3-diamino- and 1-amino-3-azidoindazoles. These products undergo slow autoxidation in chloroform solution to give 4-aminobenzo-1,2,3-triazine. The action of formic or acetic acid on 3-amino-1-benzylideneaminoindazole leads to recyclization and formation of 3-amino-2-benzylindazole, which is also formed in the catalytic hydrogenation of 1-benzylamino-3-nitro- and 1-benzylideneamino-3-nitroindazoles.     

Oxidative degradation of 8-nitroquinoline with hydrogen peroxide in acetic acid a possible mechanism through 3,4-epoxide of quinoline ring

The treatment of 8-nitroquinoline with hydrogen peroxide and acetic acid at 60°C afforded 7-nitroindole, 7-nitro-2-oxindole, 2-amino-3-nitrobenzoic acid, 2-amino-3-nitrobenzaldehyde, 3,4-dihydro-3, 4-trans-dihydroxy-8-nitrocarbostyril, 3,4-trans-dihydro-3-hydroxy-4-acetoxy-8-nitrocarbostyril, and 1-(2-amino-3-nitrophenyl)-2-hydroxy-ethanone. The reaction mechanism acceptable in elucidating the formation of these products involves, at the initial step of reaction, an epoxidation of the 3,4-double bond of the 1,2-dihydro adduce of quinoline ring.     

Syntheses of substituted 2-(1-methyl-5-nitro-2-benzimidazolyl)quinolines

Reaction of N-methyl-2-amino-4-nitroaniline ( 1 ) with lactic acid afforded 2-(1-hydroxyethyl)-1-methyl-5-nitrobenzimidazole ( 2 ). Oxidation of compound 2 with chromic acid in acetic acid gave 2-acetyl-1-methyl-5-nitrobenzimidazole ( 3 ). Reaction of compound 3 with substituted 2-aminobenzaldehyde ( 4 ) under basic conditions yielded substituted 2-(1-methyl-5-nitro-2-benzimidazolyl)quinolines ( 5 ). Condensation and cyclization of o-aminoacetophenone (or substituted o-aminobenzophenones) with compound 3 under acetic condition afforded compound 7 . Condensation and cyclization of compound 1 with indole-3-carboxaldehyde ( 11 ) in ethanol in the presence of excess nitrobenzene gave 3-(1-methyl-5-nitro-2-benzimidazolyl)indole ( 12 ).     

Reductive acetylation of nitrocarboxylic acids of the thiophene and furan series or their esters

The corresponding 4-acetylamino-2-thiophenecarboxylic acids or their esters were produced by the action of reduced iron on solutions of 4-nitro-2-thiophenecarboxylic acid, its derivatives, or their esters in a mixture of acetic acid and acetic anhydride. Esters of 5-acetylamino-2-thiophenecarboxylic or 5-acetylamino-2-furancarboxylic acids are formed from esters of 5-nitro-2-thiophenecarboxylic or 5-nitro-2-furancarboxylic acids. Free 5-nitro-2-thiophenecarboxylic and 5-nitro-2-furancarboxylic acids are entirely decomposed under the conditions of reductive acetylation by iron. The ester of 5-acetylamino-3-thiophenecarboxylic acid was obtained from the methyl ester of 5-nitro-3-thiophenecarboxylic acid.     

Deuteriation of nitrobenzoic acids in the presence of divalent platinum catalyst

The kinetic behavior of deuteriation of nitrobenzoic acids has been studied at 130 °C in the presence of homogenous platinum salt catalyst in a medium containing deuteriated acetic acid in heavy water. The quasiunimolecular H/D exchange rate constants for particular position of aromatic ring hydrogens were determined by proton NMR integration signal. The difference in the kinetics patterns of H/D exchange has been shown for the 2-nitro-, 3-nitro- and 4-nitrobenzoic acid.     

Indole rings in palladium(II) complexes. Dual mode of metal binding and aromatic ring stacking causing syn-anti isomerism

In view of the interesting metal-binding properties of lichen substances and the indole ring as a potential ligand, we studied the Pd(II) complexes of indole-containing ligands, N-(indole-3-ethyl)-Delta(2,11)-enaminousnic acid (IEU) and 4-[2-(indol-3-yl)-ethylamino]pent-3-en-2-one (IEP) obtained by condensation of tryptamine with usnic acid and its model acetylacetone, respectively. Reactions of Pd(II) with IEU and IEP gave isomeric complexes resulting from coordination of the C3 atom of the indole ring in the 3H-indole form, Pd2(IEUH(-2))(2) (1 and 2) and Pd2(IEPH(-2))(2) (3 and 4) (IEUH(-2) and IEPH(-2) denote doubly deprotonated forms of IEU and IEP, respectively). Complexes 1-4 were determined, from the NMR and MS spectra, to have dimeric structures doubly bridged by the indole rings, which were stacked in different orientations. X-ray crystal structure analysis of 3 and 4 established that they are indole-bridged dimers of the [C,N,O]-donor palladacycles with the Pd(II) centers in a square-planar geometry formed by a CN(2)O donor set and are anti and syn isomers with respect to the bridging indole rings, respectively. On the basis of the spectral similarity with 4, 1 and 2 were concluded to be stereoisomers assuming the syn form with the same donor set. The results demonstrate the metal binding and stacking abilities of the indole ring and the stereoisomerism from the sp3 C3 atom formed upon coordination.     

Nitration of 2- and 4-[2-(2-furyl)vinyl]thiazole derivatives

Nitration of 4-methyl-2-[2-(nitro-2-furyl)vinyl]thiazole with a mixture of concentrated nitric and sulfuric acids leads to 4-methyl-5-nitro-2-[2-(3,5-dinitro-2-furyl)vinyl]thiazole. Under the same conditions 2-methyl- and 2-acetamido-4-[1-R-2-(5-nitro-2-furyl)vinyl]thiazoles (R=CH₃, Cl) are nitrated in the 3 position of the furan ring, 2-amino-4-[1-chloro-2-(5-nitro-2-furyl)vinyl]thiazole is nitrated in the 5 position of the thiazole ring and 2-acetamido-5-nitro-4-[2-(2-furyl)vinyl]thiazole undergoes profound changes. Under the influence of a mixture of of nitric acid and acetic anhydride the latter compound is converted quantitatively to the 5-nitro derivative (with respect to the furan ring), whereas 4-[2-(5-nitro-2-furyl)vinyl]thiazole derivatives do not undergo reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 314–317, March, 1977.     

α-(2-Furyl)quinoxalines and -quinoxal-2-ones with a substituent in the benzene ring

Isomeric 2-(2-furyl)quinoxalines or 3-(2-furyl)quinoxal-2-ones with a substituent in various positions in the benzene ring are formed in the reaction of 2-furylglyoxal or 2-furylglyoxylic acid with 6-hydroxy- or 4-nitro-1,2-diaminobenzene. The structures of the synthesized isomers were confirmed by PMR spectroscopy and their dipole moments.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1311–1314, October, 1977.     

Nitration of furan derivatives with acetyl nitrate

The mixture of products formed in the nitration of methyl furan-2-carboxylate in acetic anhydride was separated by means of thin-layer and column chromatography. It was found that products of cis and trans addition of acetyl nitrate to the furan ring — methyl 5-nitro-2-ace-toxy-2,5-dihydrofuran-2-carboxylate and 5-nitro-4-acetoxy-4,5-dihydrofuran-2-carboxylate — and methyl 5-nitrofuran-2-carboxylate are formed in the nitration.     

1H‐Pyrrolo[2,3‐b]pyridine‐3‐acetic acid as a molecular probe for use in auxin physiology

The structural characterization of 1H‐pyrrolo­[2,3‐b]­pyridine‐3‐acetic acid (alternative name: 7‐aza­indole‐3‐acetic acid), C₉H₈N₂O₂, reveals similar molecular geometry, i.e. with the side chain perpendicular to the 7‐aza­indole ring, to that of the natural plant growth hormone indole‐3‐acetic acid (auxin) and its alkyl­ated and halogenated derivatives.     

Regioselective and stereoselective nucleophilic ring opening reactions of a phenyl-substituted aziridine: enantioselective synthesis of beta-substituted tryptophan, cysteine, and serine derivatives

The asymmetric synthesis of beta-phenyl-substituted cysteine, tryptophan, and serine derivatives was successfully developed. In this approach, the key intermediate, enantiomerically pure 3-phenylaziridine-2-carboxylic ester 7, was prepared from alpha,beta-unsaturated ester 1 by employing the Sharpless asymmetric dihydroxylation. The aziridine 7 was treated with 4-methoxybenzylthiol, indole, and acetic acid to give beta-phenyl-substituted cysteine, tryptophan, and serine, respectively, in a clean S(N)2 type ring opening at the C3 position. This general approach can be used to synthesize a variety of beta-substituted novel amino acids.     

A kinetic and mechanistic study on the oxidation of indole‐3‐acetic acid by peroxodisulfate

The kinetics of oxidation of indole‐3‐acetic acid (IAA) by peroxodisulfate (PDS) has been carried out in aqueous acetic acid medium. First‐order dependence of rate each with respect to [IAA] and [PDS] was observed. The reaction rate was unaffected by added [H⁺]. Increase of percentage of acetic acid decreased the rate. Variation of ionic strength (μ) had negligible influence on the rate. A suitable kinetic scheme based on these observations involving a nonradical mechanism is proposed. The reactivity of peroxodisulfate toward indole‐3‐acetic acid was found to be lower than that with peroxomonosulfate. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 355–360, 2005     

Total synthesis of (-)-indolactam V

The total synthesis of protein kinase C activator (-)-indolactam V (IL-V) has been successfully completed with two separate approaches: From known 4-nitrotryptophan derivative 3 in 8 steps (49% overall yield) and from L-glutamic acid in 12 steps (18% overall yield), where 4-nitrotryptophanol derivative 4 served as a key intermediate. Derivatives 3 and 4, both incorporating indole 4-substitution and the C-9 stereocenter in IL-V, were synthesized via the Pd-catalyzed indole synthesis from 3-nitro-2-iodoaniline 5 with aldehydes 6 and 7, respectively. Aldehyde 7 was, meanwhile, synthesized from l-glutamic acid in 5 steps (68% yield). Lactamization of the 9-membered ring was achieved using HATU in THF in good yield.     

PHOTO-OXIDATION OF N'-FORMYLKYNURENINE AND TRYPTOPHAN PEPTIDES BY SUNLIGHT OR SIMULATED SUNLIGHT

Abstract— N'-Formylkynurenine, a photochemical breakdown product of tryptophan in proteins, was exposed to sunlight or simulated sunlight at neutral pH. N-Formylanthranilic acid and 4-hydroxyquinoline were identified in the reaction products. Neither has been previously described as a photo-oxidation product of tryptophan-containing compounds. They were not found after photo-oxidation of glycyltryptophan or tryptophylglycine, although the indole ring was broken in both compounds.     

Indole derivatives

It was shown that it is possible to introduce an ethynyl group into an indole ring by the acetylenic cleavage of an acyl derivative of a base. 1-Methyl-5-nitro-2-ethynylindole was obtained from 1-methyl-5-nitro-2-indolcarboxylic acid, and a series of mono- and diaminomethyl derivatives was prepared by the Mannich reaction.Communication 131 [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1472–1475, November, 1988.     

The chemistry of indole

A number of amides of indole ketoacids are synthesized. 3-Carboxyacylindoles can be converted to the corresponding enol-lactones by treatment with acetic anhydride or acetyl chloride. Reaction of the lactones with ammonia or amines involves lactone ring opening, and this makes it possible to prepare some N-substituted or unsubstituted ketoacid amides. Deacylation can occur in the action of strong bases or high temperatures on indoleketoacids. Reaction of 2-(indolyl-3') benzoic acid with dimethyl sulfate proceeds in two ways: the NH group is methylated, and there is conversion to the corresponding indolenine, with subsequent methylation of the enol.For Part II see [1].     

Different specificities in the bromination of 6-(2-furyl)imidazo[2,1-b]thiazole and its derivatives with 1 mole of bromine

The action of 1 mole of bromine on 6-(2′-furyl)imidazo[2,1-b]thiazole, its 2-methyl-, 3-methyl-, and 2,3-dimethyl-substituted derivatives, and their hydrobromides in chloroform and glacial acetic acid was studied. The bromination of bases containing a methyl group in the 3 position leads primarily to the 5′-derivatives with respect to the furan ring in chloroform, whereas in the remaining cases 5-bromo derivatives with respect to the imidazothiazole system are formed. Compounds of the latter type are formed by the action of bromine in glacial acetic acid or of sodium hypobromite in alkaline media on the bases. The hydrobromides are brominated in both acetic acid and chloroform, regardless of the substituents in the thiazole ring, primarily in the 5′ position of the furan ring. The structures of the bromination products were proved by means of alternative syntheses, thin-layer chromatography, and the PMR spectra.