Reaction of 4,5-dichloro-3-nitropyridazin-6-one with dimethylchloromethyleneammonium chloride

3,4,5-Trichloropyridazin-6-one, 3,4,5,6-tetrachloropyridzine and 4,5-dichloro-3-(N,N-dimethylamino)-pyridazin-6-one were synthesized from 4,5-dichloro-3-nitropyridazin-6-one and dimethylchloromethylene-ammonium chloride selectively.     

Reaction of pyrylium salts with heterocyclic amines

It has been established that in the reaction of 2, 4, 6-trimethylpyrylium perchlorate with 2-, 3-, and 4-aminopyridines, cytosine, adenine, guanine, and the corresponding nucleosides, and also with 2-amino-1-methylbenzimidazole, 2-amino-4-methylthiazole, 2-amino-4-phenylthiazole, 2-amino-6-bromobenzo-thiazole, and 2-amino-6-methoxybenzothiazole, either the corresponding quaternary pyridinium salt is formed or the pyrylium ring opens, depending on the basicity of the amino group.     

Reaction of 3H-oxazolo[4,5-b]pyridine-2-thione with amines

Primary amines and diethylamine react with oxazolo[4,5-b]pyridine thione to form N-(3-hydroxy-2-pyridyl)thioureas whereas cyclic secondary amines and aniline form 2-aminooxazolo[4,5-b]pyridines. Exchange of the benzene ring in benzoxazolinethione for pyridine causes the properties of the resultant oxazolopyridine-2-thione to resemble those of 5- and 6-nitrobenzoxazolinethiones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1129–1130, August, 1987.     

Reaction of 2,3-dichloro-5,6-dicyanopyrazine with enamines and some tertiary amines

The reaction of 2,3-dichloro-5,6-dicyanopyrazine ( 1 ) with enamines as well as a few tertiary amines as enamine precursors was investigated. Both reactions gave aminovinyl-substituted pyrazine derivatives. During the attempted purification of 3c or 3d by column chromatography on silica gel, 2-chloro-5,6-dicyano-3-(1′-oxocyclopent-2′-yl)pyrazine ( 4 ) was obtained, apparently by hydrolytic cleavage. The products prepared are all of interest as potential pesticides.     

Reaction of 2,4,6-trimethyl- and 2,4,6-triphenylpyrylium perchlorates with heterocyclic amines

2,4,6-Triphenylpyrylium perchlorate reacts with most heterocyclic amines in dimethylformamide to give quaternary pyridinium salts. 2,4,6-Trimethylpyrylium perchlorate forms similar products only up to a certain limit of the basicity of the amine, below which a proton is transferred from the-methyl group of the pyrylium salt to the pyridine nitrogen atom of the heteroring to give the perchlorate of the starting heterocycle. The residual 2,6-dimethyl--methylenepyran is polymerized to a hexamer.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1461–1467, November, 1974.     

Reaction of 3-phenylsulfonylbenzothiazclone with amines

A phenylsulfonyl group in the 3 position accelerates and changes the direction of aminolysis of benzothiazolone and leads to the formation of 2-phenylsulfonylamino-S-phenyl esters of N-substituted thiocarbamic acids. 2,2-Bis(phenylsulfonylamino)diphenyl disulfide and the corresponding symmetrical ureas were obtained in the reaction with several primary amines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1192–1195, September, 1976.     

The structure of 6-tert-butyl-4,5-dichloro-3-ethyl-4,5-dihydro-2,1-benzoisoxazole

X-ray structural analysis revealed that the product of the reaction of 3,6-dialkyl-substitutedN-oxo-2,1-benzoisoxazolinium sulfate with hydrochloric acid is 6-tert-butyl-4,5-dichloro-3-ethyl-4,5-dihydro-2,1-benzoisoxazole.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 862–864, May, 1994.     

Synthesis of 4,5-dichloro-3-cyanoisothiazole and its functional derivatives

By treating with phosphorus pentoxide the 4,5-dichloroisothiazole-3-carboxamide 4,5-dichloro-3-cyanoisothiazole was synthesized whose reactions with piperidine, phenyl-and benzylthiols occurred with replacement of the chlorine atom in the position 5 by the residue of the corresponding nucleophile. Reactions with sodium thiobytylate and also with sodium methylate in methanol led to the formation both of the products of chlorine substitution by BuS or MeO groups respectively and of addition products of methanol to the cyano group. The reaction of butanethiol with cyanoisothiazole in 2-propanol in the presence of sodium 2-propylate was more selective and resulted in the replacement of the chlorine atom in the position 5 by the residue of the butanethiol.     

Synthesis of 4,5-dichloro-1-(4,5-dichloropyridazin-3-yl)pyridazin-6-one

This paper presents the synthesis of 4,5-dichloro-1-(4,5-dichloropyridazin-3-yl)pyridazin-6-one from 4,5-dichloropyridazin-6-one.     

Reaction of cis-3-bromo-1,2-dibenzoylpropene with amines

The reaction of cis-3-bromo-1,2-dibenzoylpropene (1) with amines proceeds by means of a substitution-rearrangement attack to give the 2-(α-aminoacetophenonyl)acrylophenones ( 2 ). Like similar structures, 2 undergoes further substitution-rearrangement by amines to give 3-benzoyl-5-phenylpyrroles ( 5 ) and an enaminoketone, α-acetophenonyl-β-aminoacrylophenone ( 3 ). Competitive with substitution-rearrangement, amine addition to 2 followed by loss of hydrogen and then water leads to formation of the 3-benzoyl-4-amino-5-phenylpyrroles ( 4 ). The enaminoketones ( 3 ) by contrast with 2 are quite stable. Structure 2 when in polar solvents or in the presence of amines undergoes substitution-rearrangement to give 3 , which can be induced to give the pyrroles ( 5 ) when exposed to acid conditions. When neat or in solvents of low polarity, 2 undergoes intermolecular substitution-rearrangement-dehydration to give 5 almost exclusively. A novel addition reaction of 3-benzoyl-5-phenylfuran involving attack by isopropyl- or cyclohexylamine provides a quantitative method of synthesizing the appropriate N-substituted examples of 3 and an efficient method of deriving the corresponding pyrroles ( 5 ).     

Nucleophilic substitution in 1-alkyl-4,5-dichloro-3-nitropyridazin-6-ones

Treatment of 1-alkyl-4,5-dichloro-3-nitropyridazin-6-one with C-nucleophiles and with ambident nucleophiles (2-azahetarylacetonitriles) leads to a selective substitution of a chorine atom by the quaternary carbon atom of the carbanion formed from a substituted acetonitrile. The pK_a of the CH-acid 2-(1-alkyl-5-chloro-3-nitro-6-oxo-1,6-dihydro-4-pyridazinyl)malononitrile was determined by potentiometric titration. Reaction of 2-(1-alkyl-5-chloro-3-nitro-6-oxo-1,6-dihydro-4-pyridazinyl)-2-hetarylacetonitriles with primary amines gives 6,7-dihydro-1H-pyrrolo[2,3-d]pyridazin-7-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 556–564, April, 2006.     

Analysis of heterocyclic aromatic amines

Heterocyclic aromatic amines are formed in protein and amino acid-rich foods at temperatures above 150 °C. Of more than twenty heterocyclic aromatic amines identified ten have been shown to have carcinogenic potential. As nutritional hazards, their reliable determination in prepared food, their uptake and elimination in living organisms, including humans, and assessment of associated risks are important food-safety issues. The concentration in foods is normally in the low ng g⁻¹ range, which poses a challenge to the analytical chemist. Because of the complex nature of food matrixes, clean-up and enrichment of the extracts are also complex, usually involving both cation-exchange (propylsulfonic acid silica gel, PRS) and reversed-phase purification. The application of novel solid-phase extraction cartridges with a wettable apolar phase combined with cation-exchange characteristics simplified this process—both the polar and apolar heterocyclic aromatic amines were recovered in one fraction. Copper phthalocyanine trisulfonate bonded to cotton (“blue cotton”) or rayon, and molecular imprinted polymers have also been successfully used for one-step sample clean-up. For analysis of the heterocyclic aromatic amines, liquid chromatography with base-deactivated reversed-phase columns has been used, and, recently, semi-micro and capillary columns have been introduced. The photometric, fluorimetric, or electrochemical detectors used previously have been replaced by mass spectrometers. Increased specificity and sub-ppb sensitivities have been achieved by the use of the selected-reaction-monitoring mode of detection of advanced MS instrumentation, for example the triple quadrupole and Q-TOF instrument combination. Gas chromatography, also with mass-selective detection, has been used for specific applications; the extra derivatization step needed for volatilization has been balanced by the higher chromatographic resolution.     

Reaction of 3-AR(ALK)oxysulfolanes with amines

On the basis of data on the kinetics of the hydrolysis of 3-aroxysulfolanes in aqueous solutions of tertiary amines and in acetonitrile it is shown that the elimination of phenols is subject to specific base catalysis and occurs via an (ElcB)R carbanion mechanism. The exchange of aroxy and alkoxy groups of sulfolanyl ethers on reaction with nucleophilic reagents is explained by an elimination-addition scheme.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1188–1191, September, 1976.