The autoxidation of 2-(2-aminophenyl)-3- methylindole

Fischer indolisation of 2-aminophenyl ethyl ketone phenylhydrazone using glacial acetic acid saturated with hydrogen chloride as catalyst affords 3-methylindolo(l′:2′-3:4)2-methylquinazoline and 2-(2-aminophenyl)-3-methylindole. The latter compound is autoxidised to 2-(2-amino-phenyl)-3-hydroxy-3-methyl-3H-indole, a reaction which is shown to be dependent upon the presence of the primary amino group at the 2-position of the 2-phenyl substituent and which is much slower than the corresponding autoxidation of 2-(2-hydroxyphenyl)-3-methylindole to 3-hydroxy-2-(2-hydroxyphenyl)-3-methyl-3H-indole previously reported.Nitration of isopropyl phenyl ketone occurs preferentially at the ortho- rather than the meta- positions of the benzene nucleus.     

Umsetzung von 3-(Dimethylamino)-2H-azirinen mit 1,3-Oxazolidin-2-thion zu 3-(2-Hydroxyethyl)-2-thiohydantoinen

Reaction of 3-(Dimethylamino)-2H-azirines with 1,3-Oxazolidine-2-thione to 3-(2-Hydroxyethyl)-2- thiohydantoins The reaction of 3-(dimethylamino)-2H-azirines 1 and 1,3-oxazolidine-2-thione ( 6 ), in MeCN at room temperature, yields, after hydrolytic workup, 3-(2-hydroxyethyl)-2-thiohydantoins 7 (Scheme 2). In the case of the spirocyclic 1c , crystallization of the crude reaction mixture leads to spiro [cyclopentane-1, 7′(7′aH)-imidazo [4, 3-b] oxazole] -5′-thione 8c . The mechanism is discussed.     

Synthesis of 2-(2-methoxyethyl)- and 2-(2-thiomethoxyethyl)-aniline and related compounds

Summary 2-(2-Nitrophenyl)-ethanol (2) was methylated with dimethyl sulfate to give 2-(2-methoxyethyl)-1-nitrobenzene (3a) which then was reduced with hydrazine hydrate in the presence ofRaney nickel to 2-(2-methoxyethyl)-aniline (1a). Compound1a can be transformed into the N-monosilylated derivative4 by lithiation withn-butyllithium and subsequent reaction with chlorotrimethylsilane. Reaction of2 withp-toluenesulfonyl chloride yields 2-(2-nitrophenyl)-ethylp-toluenesulfonate (5), which reacts with sodium thiomethoxide to give 2-(2-nitrophenyl)-ethylp-toluenesulfonate (5), which reacts with sodium thiomethoxide to give 2-(2-thiomethoxyethyl)-1-nitrobenzene (3b).3b was reduced with hydrazine hydrate in the presence ofRaney nickel to yield 2-(2-thiomethoxyethyl)-aniline (1b). Ethyl (2-nitrophenyl)-acetate (6) could be dimethylated with methyl iodide in the presence of potassiumtert-butoxide and 18-crown-6 to give ethyl 2-methyl-2-(2-nitrophenyl)-propionate (7). Reduction of7 with lithium borohydride yields 2,3-dihydro-3,3-dimethyl-1H-indole (9) and 2-[(1-hydroxy-2-methyl)-2-propyl]-aniline (10).

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Synthese von 2-(2-Methoxyethyl)- und 2-(2-Thiomethoxyethyl)-anilin und verwandten Verbindungen

Zusammenfassung 2-(2-Nitrophenyl)-ethanol (2) wurde mit Dimethylsulfat zu 2-(2-Methoxyethyl)-1-nitrobenzol (3a) methyliert, das sich mit Hydrazinhydrat in Gegenwart vonRaney-Nickel zu 2-(2-Methoxyethyl)-anilin (1a) reduzieren läßt. Verbindung1a kann durch Metallierung mitn-Butyllithium und anschließende Reaktion mit Chlortrimethylsilan in dasN-monosilylierte Derivat4 umgewandelt werden. Reaktion von2 mitp-Toluolsulfonylchlorid ergab 2-(2-Nitrophenyl)-ethyl-p-Toluolsulfonat (5), das mit Natriumthiomethanolat zu 1-Nitro-2-(2-thiomethoxyethyl)-benzol (3b) reagiert.3b wurde mit Hydrazinhydrat in Gegenwart vonRaney-Nickel zu 2-(2-Thiomethoxyethyl)-anilin (1b) reduziert. Ethyl-2-(nitrophenyl)-acetat (6) kann mit Methyliodid in Gegenwart von Kalium-tert-butoxid und 18-Krone-6 zu Ethyl-2-methyl-2-(2-nitrophenyl)-propionat (7) dimethyliert werden. Reduktion von7 mit Lithiumborhydrid lieferte 2,3-Dihydro-3,3-dimethyl-1H-indol (9) und 2-[(1-Hydroxy-2-methyl)-2-propyl]-anilin (10).

     

Synthesis and properties of 2-(2-furyl)-and 2-(2-Thienyl)-1,3-benzoxazoles

Condensation of o-aminophenol with furoyl and thenoyl chlorides in 1-methylpyrrolidin-2-one gave, respectively, 2-(2-furyl)- and 2-(2-thienyl)-1,3-benzoxazoles in which the furan and thiophene rings showed no acidophobic properties. Reactions of 2-(2-furyl)- and 2-(2-thienyl)-1,3-benzoxazoles with electrophilic reagents (acylation, bromination, nitration, and sulfonation) afforded products of hydrogen replacement in both hetaryl and benzene rings, depending on the conditions.     

2-[2-(2,3-Dihydrobenzimidazolylidene)]- and 2-[2-(2,3-Dihydropyrido[2,3-d]imidazolylidene)]-5,5-dimethyl-1,3-cyclohexanediones

The reaction of 2-aminocarbonyl-5,5-dimethyl-1,3-cyclohexanedione with 2,3-diaminopyridine, 1,2-phenylenediamine (and its 4-methyl, 4-nitro, 4-carboxy, and 4-benzoyl derivatives), and 3,3-diaminobenzidine gave the corresponding 2-[2-(2,3-dihydrobenzimidazolylidene)]- and 2-[2-(2,3-dihydropyrido[2,3-d]imidazolylidene)]-5,5-dimethyl-1,3-cyclohexanediones. Their structure was confirmed by ¹H NMR spectroscopic data and X-ray analysis.     

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.     

2-(2-hydroxyphenyl)-2-adamantanol in Ritter reaction

2-Substituted 4H-1,3-benzoxazines were obtained by the condensation of 2-(2-hydroxyphenyl)-2-adamantanol with aromatic and aliphatic nitriles in trifluoroacetic acid. With acetonitrile the classic product of Ritter reaction, a secondary amide, was isolated.     

Synthesis and Properties of 2-(2-Furyl)- and 2-(2-Thienyl)-1-methylphenanthro[9,10-d]imidazoles

Condensation of 9,10-phenanthrenequinone with 2-furaldehyde and 2-thiophenecarbaldehyde in glacial acetic acid in the presence of ammonium acetate gave 2-(2-furyl)- and 2-(2-thienyl)phenanthro[9,10-d]imidazoles which were converted into the corresponding 1-methyl derivatives. The furan and thiophene rings in the products lose their acidophobic properties. Depending on the conditions, electrophilic substitution reactions in 2-(2-furyl)- and 2-(2-thienyl)phenanthro[9,10-d]imidazoles occur both at the furan (thiophene) and phenanthrene moieties.     

1-(Fluoren-2-yl)-2-(2-azafluoren-3-yl)ethene and 1-(fluoren-2-yl)-2-(2H,2-methylindeno[2,3-c]pyridine)ethene

Condensation of 3-methyl-2-azafluorene with 2-formylfluorene results in the formation of a compound containing a polyconjugated system and two acidic CH centers, namely, 1-(fluoren-2-yl)-2-(2-azafluoren-3-yl)ethene. The conversions of this compound upon treatment with alkali have been studied by electronic absorption spectroscopy. The methyl iodide derivative of this base was used as an intermediate in the preparation of a pseudo-azulene, 1-(fluoren-2-yl)-2-(2H, 2-methylindeno[2,3-c]pyridine)ethene.Translated from Khimiya Geterotsiklicheskikh Soedinenii No. 5, pp. 657–659, May, 1987.     

Sulfonated 1-(2-pyridylazo)-2-naphthols and 2-(2-pyridylazo)-1-naphthols as spectrophotometric reagents: Determination of nickel

Three sulfonated 1-(2-pyridylazo)-2-naphthols and six sulfonated 2-(2-pyridylazo)-1-naphthols were synthesized, and their application to the spectrophotometric determination of metals was studied. The acidity constants of the reagents and the stability constants of the nickel chelates are reported, and the relationship between their properties and the position of the sulfonic acid group is discussed. 1-(2-Pyridylazo)-2-naphthol-6-sulfonic acid (PAN-6S) and 1-(2-pyridylazo)-2-naphthol-7-sulfonic acid (PAN-7S) are sensitive and selective reagents for nickel. The determination of nickel in the presence of cobalt with PAN-6S is described. Extraction of the chelate as the ion-pair with tetraphenylarsonium ions into chloroform is suitable for the determination of 1–10 μg Ni at 570 nm; the molar absorptivity is 56 000 l mol^-1 cm^-1, and interferences are easily avoided.     

Synthesis of Ethyl 2-Hydroxy-3-[aryl(2-naphthylamino)methyl]-2-cyclopentenecarboxylates and Ethyl 3-Arylmethylene-2-(2-naphthylamino)-1-cyclopentenecarboxylates

Condensation of N-arylmethylene-2-naphthylamines with ethyl 2-oxocycopentanecarboxylate in the presence of HCl or CH₃COOH yields ethyl 2-hydroxy-3-[aryl(2-naphthylamino)methyl]-2-cyclopentenecarboxylates and ethyl 3-arylmethylene-2-(2-naphthylamino)-1-cyclopentenecarboxylates, respectively.     

2'-O-[2-(amino)-2-oxoethyl] oligonucleotides

[structure: see text] Oligonucleotides with novel modifications, 2'-O-[2-(amino)-2-oxoethyl] (2'-O-NAc), 2'-O-[2-(methylamino)-2-oxoethyl] (2'-O-NMAc), 2'-O-[2-(dimethylamino)-2-oxoethyl] (2'-O-DMAc), and 2'-O-[2-[[2-(dimethylamino)ethyl]amino]-2-oxoethyl] (2'-O-DMAEAc), have been synthesized. These modified oligonucleotides exhibit high binding affinity to complementary RNA (and not to DNA) and considerably enhance the nuclease stability of oligonucleotides with t(1/2) > 24 h.     

Stereoselective synthesis of (6S)-5,6-dihydro-6-[(2R)-2-hydroxy-6-phenylhexyl]-2H-pyran-2-one

A stereoselective synthesis of (6S)-5,6-dihydro-6-[(2R)-2-hydroxy-6-phenylhexyl]-2H-pyran-2-one is reported. The strategy utilizes an olefin cross-metathesis, syn-benzylidene acetal formation and a preferential (Z)-Wittig olefination reaction and lactonization as the key steps.     

Crystal structure of [2-(2-hydroxybenzilydene)-hydrazinecarboxoamidato(1-)][2-(2-hydroxybenzilydene)-hydrazinecarboxoamidato(2-)]chromium monohydrate

The crystal structure of [2-(2-hydroxybenzilydene)hydrazinecarboxoamidato(1-)][2-(2-hydroxy-benzilydene)hydrazinecarboxoamidato(2-)]chromium monohydrate [Cr(HL)(L)]·H₂O (I), where H₂L is salicylaldehyde semicarbazone, is determined. In I the central chromium atom is octahedrally surrounded by two ligand anions in the mer position and coordinated azomethine nitrogen atoms, phenol and carbamide oxygen atoms. In both ligands phenol groups are deprotonated; in one of them the imine group is also deprotonated. In the crystal, complexes of the compound studied are hydrogen bonded into layers along the [100] direction, with π-π stacking being observed between the phenyl rings inside the layer along with the X-H…Cg (π ring) interaction.     

Cyclization reactions of 2-(2-chloro-4-nitrophenylsulfonyl)-1-(2-thienyl)ethanone

A new sulfonyl group-containing heterocyclic compound 2-(2-chloro-4-nitrophenylsulfonyl)-1-(2-thienyl)ethanone 2 was prepared from the corresponding sulfide 2-(2-chloro-4-nitrophenylthio)-1-(2-thienyl)ethanone 1 . Two different cyclization reactions of the compound 2 were discussed. In contrast to the tandem alkylation-cyclization process [1], another cyclic procedure was described. In the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene as a base and dimethylformamide as a solvent, compound 2 was treated with ethyl acrylate or methyl methacrylate at 50–55° to give the 1,4-benzoxathiin 4,4-dioxide 5 or 6 respectively via a tandem Michael conjugate addition-cyclization process.     

Synthesis of substituted in benzene ring 4-[(2-aminophenyl)thio]-, 4-[(2-mercaptophenyl)amino]-2-methylquinolines and (4E)-4-[(2-mercaptophenyl)imino]-2-methyl-1,4-dihydroquinolines

By a reaction of 2-methyl-4-chloroquinolines with o-mercaptoaniline under various conditions synteses were performed of substituted in the benzene ring 4-[(2-aminophenyl)thio]-2-methylquinolines and (4E)-4-[(2-mercaptophenyl)imino]-2-methyl-1,4-dihydroquinolines that were respectively by isomerization or rearrangement converted into 4-[(2-mercaptophenyl)amino]-2-methylquinolines.     

2-(Acylmethylmercapto)-3-amino- and 2-(acylmethylmercapto)-3-acetamidopyridines

The reaction of 2-mercapto-3-acetamido-5-(or 6-)chloropyridines with phenacyl bromide and substituted phenacyl bromides yielded 2-(phenacylmercapto)-3-acetamidopyridines, while the reaction of the former with -chloroacetoacetic ester yielded 2-(carbethoxyacyl-methylmercapto)-3-acetamidopyridlnes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1391–1394, October, 1971.     

Preparations of bis[2-(2-arylethynyl)-3-thienyl]arenes and bis[2-{2-(trimethylsilyl)ethynyl}-3-thienyl]arenes

4,4′-Bis[2-(2-phenylethynyl)-3-thienyl]biphenyl, 4,4′-bis[2-{2-(trimethylsilyl)ethynyl}-3-thienyl]biphenyl and their congeners were prepared and their properties were studied. Extension of π-system through the central benzene ring was suggested by UV-vis spectra. Connection of two 1,4-bis[2-{2-(trimethylsilyl)ethynyl}-3-thienyl]benzene units was exemplified.     

Proton-controlled photoisomerization of 1-(2-pyridyl)-2-(2-quinolyl)ethylene

Quantum-chemical calculations (B3LYP/6-31G*) predict the formation of intramolecular hydrogen bond (IMHB) in the monoprotonated Z-isomer of 1-(2-pyridyl)-2-(2-quinolyl)ethylene (2P2Q), with this bond stabilizing the isomer relative to its E-counterpart. An experimentally observed increase in the quantum yield of trans-cis photoisomerization (φ_tc) by more than an order of magnitude (from 0.033 to 0.42 in acetonitrile) on passing from the neutral to the monoprotonated form of 2P2Q can be associated with IMHB, which manifested itself in the spectral properties of the Z-isomer. The IMHB breaks in the diprotonated form, and the value of φ_tc decreases back to the initial value. In addition to the photoisomerization, the photoreduction and photoaddition reactions of solvent molecules have been observed in an ethanol solution of 2P2Q.     

Synthesis of Esters of 3-(2-Aminoethyl)-1H-indole-2-acetic Acid and 3-(2-aminoethyl)-1H-indole-2-malonic acid (= 2-[3-(2-aminoethyl)-1H-indol-2-yl]propanedioic acid) 4th communication on indoles,indolenines, and indolines

Alkyl 3-(2-aminoethyl)-1H-indole-2-acetates 6a and 6b are synthesized starting from methyl 1H-indole-2-acetate (2) via methyl 3-(2-nitroethenyl)-1H-indole-2-acetate (4) and the alkyl 3-(2-nitroethyl)-1H-indole-2-acetates 5a and (Scheme 1). Analogously, diisopropyl 3-(2-aminoethyl)-1H-indole-2-malonate 20b is obtained from diisopropyl 1H-indole-2-malonate 11c (Scheme 4). An alternative synthesis of 20a and 20b follows a route via 15–18 and the dialkyl 3-(2-azidoethyl)-1H-indole-2-malonates 19a and 19b , respectively (Scheme 3). The aminoethyl compounds 6a and 20a are easily transformed into lactams 7 and 21 , respectively. Procedures for the preparation of the indoles 2 and 11a and of the alkylating agent 14 are described. A tautomer 12 of 11a is isolated.