Reaction of 2-alkoxycarbonylmethyl derivatives of δ2-oxazoline and δ2-imidazoline and their tautomers with 4-nitrobenzonitrile N-oxide

It was established that 2-alkoxycarbonylntethylene derivatives of oxazolidine and imidazolidine react readily with 4-nitrobenzonitrile N-oxide; the reaction takes place at the methylidyne carbon atom to give intermediate oximes, which can then undergo cyclization to isoxazoles. Their tautomers —benzimidazole and ² -oxazoline derivatives —react with considerably greater difficulty; in the first case the reaction takes place at a different center, viz., the ring nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 681–684, May, 1991.     

Reaction of 4-cyano-5-aminopyrazole and 3,4-dicyano-5-aminopyrazole with dimethylformamide diethylacetal

The condensation of 4-cyano-5-aminopyrazole or 3,4-dicyano-5-aminopyrazole with dimethylformamide diethylacetal was studied. It was shown that, in addition to the formation of dimethylaminomethyleneamino derivatives, alkylation of the pyrazole ring occurs under severe conditions without a solvent. Only the corresponding formamidino derivatives are formed when the same reactions are carried out in methanal under milder conditions. The site of addition of an ethyl group to the pyrazole ring in the N-alkyl derivatives obtained was established by ¹³C NMR and PMR spectroscopy. The possibility of the synthesis of 4-amino- or 4-methylmercaptopyrazolo[3,4-d]pyrimidines by cyclization of the corresponding dimethylamino- methyleneaminopyrazoles with a cyano group in the ortho position was demonstrated for the first time.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 259–264, February, 1984.     

Synthesis of benzo[g]quinoline derivatives

It has been established that the cyclization of -(2-carboxy-3-naphthylamino)propionic acid into N-acetyl-4-oxo-1, 2, 3, 4-tetrahydrobenzo[g]quinoline takes place with the participation of acetic anhydride and an alkali metal acetate. In the absence of the alkali metal acetate cyclization takes place in a different direction. A mechanism for this reaction has been proposed as taking place through the formation of an internal mixed anhydride, which decomposes under the reaction conditions into N-acetyl-4-oxo-1, 2, 3, 4-tetrahydrobenzo[g]-quinoline and carbon dioxide.For part V, see [1].     

Acetals of lactams and acid amides

The reaction of dimethylformamide diethylacetal with -cyano--dimethylaminoacrylamide proceeds at the NH₂ amide group to give the corresponding acylformamidine, from which 3-cyano-4-dimethylamino-2-pyridone was obtained by thermal cyclization. Pyrrolo-, pyrido-, and azepino-[3,2-c]pyridine derivatives were similarly synthesized from 1-methyl-2-(2-cyano-2-carbamido)-methylenepyrrolidine and the homologous six- and seven-membered enaminoamides.See [1] for communication XVII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1509–1512, November, 1976.     

Preparation and electrophilic cyclization of multisubstituted dienamides leading to cyclic iminoethers

Stereodefined multisubstituted dienamides could be concisely prepared in high yields by direct addition of 1-lithiobutadiene derivatives to both N-aryl and N-alkyl isocyanates. Electrophilic cyclization of these dienamides was achieved to generate substituted cyclic iminoethers in excellent yields with perfect selectivity. When treated with 12 N aqueous HCl, dienamides underwent efficient and selective electrophilic cyclization to afford cyclic imidate derivatives. When treated with NBS, monobrominated or double-brominated cyclic iminoethers were formed.     

Acetals of lactams and acid amides. 41. Enamino amides in the synthesis of pyrimidine derivatives

The reaction of -cyano--dimethylaminomethyleneacrylamide with arylamines was used to synthesize -cyano--arylaminoacrylamides, which react readily with dimethylformamide diethylacetal to give the corresponding N-dimethylaminomethylene derivatives. The latter undergo cyclization to 1-aryl-5-cyano-4-pyrimidinones when they are heated in dimethylformamide or acetic anhydride and to pyrimido-[5,4-c]quinolone derivatives when they are heated in glacial acetic acid.See [1] for communication 40.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 538–542, April, 1984.     

Reaction of 2-Tetrafluoropropoxy-5,6-benzo-1,3,2-dioxaphosphorinan-4-one with Pyruvonitrile

The reaction of pyruvonitrile with 2-tetrafluoropropoxy-5,6-benzo-1,3,2-dioxaphosphorinan-4-one results mainly in the enlargement of the starting heteroring to form 4-cyano-4-methyl-2-tetrafluoropropoxy-6,7-benzo-1,3,2⁵-dioxaphosphepin-5-one 2-oxide as a mixture of two diastereomers (14:1) along with minor amounts of 3-cyano-3-methyl-2-tetrafluoropropoxy-6,7-benzo-1,4,2⁵-dioxaphosphepin-5-one 2-oxide.     

Research in the chemistry of heterocyclic quinone imines. 11. Effect of benzannelation on the oxidative cyclization of diarylamino-N-aryl-1,4-benzoquinone monoimines to phenazinone derivatives

2,5-Diarylamino-N-()-naphthyl-1,4-benzoquinone monoimines undergo oxidative cyclization to give benzannelated phenazinone derivatives. The effect of an N-aryl fragment on the ease of cyclization decreases in the order N--naphthyl>N--naphthyl>N-phenyl. 2-Arylamino-N-phenyl-1,4-naphthoquinone monoimines do not undergo oxidative cyclization to phenazinones.See [1] for Communication 10.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 786–790, June, 1991.     

Synthesis and properties of azoles and their derivatives. 25. Electron-impact mass spectra of nitro- and nitroalkyl-substituted 3-aryl-δ2-isoxazolines

The fragmentation of nitro and nitroalkyl derivatives of 3-aryl-²-isoxazolines under the influence of electron impact was investigated. It was established that the fragmentation of the molecular ions of these compounds takes place primarily through the nitro- and halogen-containing groups; other pathways of dissociative ionization include the most important pathways of the fragmentation of arylisoxazoles.See [1] for Communication 24.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 980–983, July, 1990.     

Synthesis,Characterization, and Mechanism of Polymerization of Poly(but‐2‐ene sulfide)

Summary: The effect of structural factors on polymer formation versus cyclization is reported. The reaction of sodium sulfide with either 1,4‐dibromobut‐2‐ene 1 or 1,4‐dibromobutane 2 has been carried out in presence of a phase transfer catalyst and it was observed that the former yields polymer, whereas the latter gives cyclic and linear products. Interestingly, trans/cis isomerization takes place during the polymer formation from 1 and a plausible mechanism has also been discussed.

The reaction mechanism for unsaturated compound 1 and saturated compound 2 is discussed here.     

Lewis acid-promoted direct substitution of 2-methoxy-3-cyanopyridines by organo cuprates. Part 3: Facile preparation of nicotinamide and nicotinic acid derivatives

2-Methoxy-3-cyano-4,6-diarylpyridines were subjected to Lewis acid-promoted nucleophilic displacement reactions with various organo cuprates to afford the corresponding 2,4,6-trisubstituted nicotinonitriles. Subsequent hydrolysis of compounds 10 and 11 afforded the corresponding 2,4,6-trisubstituted nicotinic acid 22 and nicotinamide 23 derivatives, respectively. The mechanism of the displacement reaction has been studied experimentally and by molecular modeling calculations.     

Azlactone Synthesis. 2-Phenyl-2-Oxazolin-5-One

Abstract

2-Phenyl-2-oxazolin-5-one (3) has been used as an intermediate in the synthesis of α-amino acids¹, derivatives of α-amino acids,² and peptides.³ Procedures for the dehydration/cyclization of hippuric acid (1) leading to the isolation of azlactone 3, have been reported using acetic anhydride,⁴ phosphorus trihalides⁵, and N, N′-dicyclohexylcarbodiimide.⁶ We report herein an alternative, high yield procedure utilizing a water soluble carbodiimide.     

Synthesis and herbicidal activity of 2-cyano-3-(2-fluoro-5-pyridyl)methylaminoacrylates

A series of 2-cyano-3-(2-fluoro-5-pyridyl)methylaminoacrylates were synthesized as herbicidal inhibitors of photosystem II (PSII) electron transport. 2-Fluoro-5-pyridinemethylamine was prepared from 2-amino-5-methylpyridine, subsequent reaction with 2-cyano-3,3-dimethylthioacrylates or 2-cyano-3-methoxyacrylates to yield these title compounds. All of these compounds were confirmed by ¹H NMR, IR, mass spectrum and elemental analyses. Their herbicidal activities were evaluated. All of the title compounds showed excellent herbicidal activities to amaranth pigweed and rape in post-emergence treatment. At the rate of 150 g/ha, one compound exhibited similar activity to Cl-analogue. The replacement of chlorine by fluorine group showed the same herbicidal activity.     

Synthesis and Chemical Conversions of 2-Chloro-3-cyano-4-methylamino-5-nitropyridine

5-Cyano-6-(-dimethylamino)vinyl-1-methyl-4-pyrimidinone was synthesized by the interaction of -cyano--(N-methylamino)crotonamide with N,N-dimethylformamide diethylacetal. Recyclization of the product in alkaline medium leads to 3-cyano-4-methylamino-2-pyridone. Nitration of the latter and transformation of the nitropyridone by boiling in POCl₃ gave 2-chloro-3-cyano-4-methylamino-5-nitropyridine. This is a key compound for various transformations including the synthesis of derivatives of dipyrido[1,2-a:3,2-e]pyrimidine, thieno[2,3-b]pyridine, and (2-pyridylamino)polyene derivatives.     

1,3-Thiazepines. 6. UV Spectroscopic and Theoretical Study of the Electronic Structures of 2-Aminotetrahydro- and 2-Iminotetrahydro-1,3-thiazepines

On the basis of studies of the electronic absorption spectra and quantum-chemical calculations of the energies and bond orders of a series of N-acetyl-N-aryl substituted 2-amino-4,5,6,7-tetrahydro-1,3-thiazepines and N-aryl substituted 2-iminohexahydro-1,3-thiazepines it has been concluded that the reason for the weak basicity of the ring nitrogen atom of the former is the acceptor properties of the amide carbonyl which obstructs the interaction of the unshared pair (USP) of this atom with the phenyl ring; in the case of the derivatives of hexahydroazepine the strengthening of the basic properties of the exocyclic nitrogen atom is associated with the conjugation of its USP with the -electrons of the benzene ring, which is strengthening by delocalisation of the USP of the sp³-hybridized ring nitrogen atom into the azomethine bond.     

New approach to the functionalization of δ-carboline derivatives

The possibility of transformation of 3-cyano-1-p-nitrophenyl--carbolin-2-one into 2-amino-3-cyano-1-p-nitrophenyl-1H-pyrido[3,2-b]indole derivatives and 2-imino-3-cyano-1-p-nitrophenyl-5H-pyrido[3,2-b]indole derivatives (-carbolines) is demonstrated. Methylation of 1-p-nitrophenyl-2-piperidino-1H--carboline followed by treatment with acetone in an alkaline medium yields 4-acetonyl-5-methyl-1,4-dihydro-5H-pyrido[3,2-b]indole derivative. The rearrangement of 2-arylimino-3-cyano-1-p-nitrophenyl-5H-pyrido[3,2-b]indoles into 2-(aryl)nitrophenylamino-3-cyano-5H-pyrido[3,2-b]indoles was accomplished on heating above the melting point or on treatment with potassium tert-butoxide. The structures of the resulting compounds were proved by ¹H and ¹³C NMR spectroscopy and X-ray diffraction analysis.     

Acetals of lactams and acid amides

The reaction of -cyano--dimethylaminocrotonic acid amide with acetals of dimethyl acetamide and N-methylbutyro-, -valero-, and -caprolactams gave enaminoacrylamidines, cyclization of which gave 3-cyano-6-dimethylamino-2-pyridone and the corresponding pyrrolo-,pyrido-, and azepino[2,3-b]pyridine derivatives.See [1] for communication XVIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1106–1109, August, 1977.     

Study of the Three-component Reaction of α-Nitrocarbonyl Compounds, Aromatic Aldehydes, and Cyanothioacetamide

The reaction of benzaldehyde, -nitro ketone, and cyanothioacetamide in the presence of morpholine has given the novel 3,4-trans-2-R-5-cyano-2-hydroxy-3-nitro-4-phenyl-1,2,3,4-tetrahydropyridine-6-thiolates. It was found that the reaction occurs via the formation of 1-amino-2-cyano-4-nitro-5-oxo-3-phenyl-1,2-pentene-1-thiolate. In the case of -nitroacetophenone, 3,4-trans-4,5-trans-5-cyano-2-hydroxy-3-nitro-2,4-diphenylhexahydropyridine-6(1H)-thione was also obtained. The use of -nitroesters in place of the nitro ketones in the reaction leads to morpholinium 2-aryl-1-carbethoxy-3-cyano-1-nitro-3-thiocarbamoylpropyl-1-ates as the single product.     

Derivatives of azaindoles. 65. Synthesis of 1-benzyl-4-methyl-5-cyano-6-hydroxy-7-azaindoline

Treatment of the ammonium (I) or benzylammonium salt of 2,6-dihydroxy-3-(-hydroxyethyl)-4-methyl-5-cyanopyridine (II) with a mixture of benzylamine and phosphorus pentoxide yielded 2-benzylamino-3-(-hydroxyethyl)-4-methyl-5-cyano-6-hydroxypyri-dine (III), which, when heated with phosphorus oxychloride, is converted to 1-benzyl-4-methyl-5-cyano-6-hydroxy-7-azaindoline (IV). The products of thermal fragmentation of II with benzylamine were studied by the method of chromato-mass spectrometry. In addition to compound III, N,N-dibenzylurea (V) and the dibenzylamide of malonic acid (VI) were preparatively isolated from the reaction products. The cyclization of I and II to 4-methyl-6-hydroxy-2,3-dihydro-7-azabenzofuran (VII) and 4-methyl-5-cyano-6-hydroxy-2,3-dihydro-7-azabenzofuran (VIII) was carried out. Heating VIII with benzylamine at 200–210°C led to compound III.For communication 64, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1105–1109, August, 1984.     

Pyrimidines. 75. Syntheses based on acetylpyrimidines. 4,6-Dihydroxy-5-acetylpyrimidine and preparation of 4′,5-bipyrimidines and their derivatives

4,6-Dihydroxy-5-acetylpyrimidine was obtained by the solvolysis of 4,6-dialkoxy-5-acetylpyrimidines. The hydrolysis of 4,6-dichloro-5-acetylpyrimidine leads to opening of the heteroring to give s-cis,trans conformera of 2-cyano-3-hydroxy-2-buteneamide. 2,4,6-Trihydroxy[4,5]bipyrimidine was obtained by the condensation of 4,6-dialkoxy-5-acetylpyrimidines with benzalbisurea. It is shown that the products of the reaction of the same ketones with benzaldehyde in the presence of sodium alkoxides are derivatives of -diketones.See [1] for Communication 74.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 378–385, March, 1985.