Synthesis of aminonicotinonitriles and diaminopyridines through base-catalyzed ring transformation of 2H-pyran-2-ones

An efficient and convenient synthesis of 2-amino-6-aryl-4-methylsulfanylnicotinonitriles (2), 2-amino-6-aryl-4-substituted-aminonicotinonitriles (4), and 2-amino-6-aryl-4-substituted-aminopyridines (6) has been delineated and illustrated through base-catalyzed ring transformation of 6-aryl-3-cyano-4-methylsulfanyl/substituted-amino-2H-pyran-2-ones (1, 3, and 5) with cyanamide and ammonium carbonate separately.     

Synthesis of 6-aryl-1,3-dimethyl-6,7-dihydro-6-azalumazin-7-(6H)ones and their conversion into 2-aryl-1,2,4-triazine-3,5-(2H,4H)odiones. A new synthesis of 1-aryl-6-azauracils

Treatment of 6-amino-5-arylazo-1,3-dimethyluracils with urea or N,N′-carbonyldiimidazole gave the respective 6-aryl-1,3-dimethyl-6,7-dihydro-6-azalumazin-7-(6H)ones, which were hydrolyzed with alkali to afford 2-aryl-2,3,4,5-tetrahydro-3,5-dioxo-1,2,4-triazine-6-carboxylic acids (1-aryl-6-azauracil-5-carboxylic acids). Thermal decomposition of these carboxylic acids gave the corresponding 2-aryl-1,2,4-triazine-3,5-(2H,4H)diones (1-aryl-6-azauracils). Methylation of the latter with methyl iodide gave the corresponding 2-aryl-4-methyl-1,2,4-triazine-3,5-(2H,4H)diones (1-aryl-3-methyl-6-azauracils).     

Synthesis of 3-aminomethyl-2-aryl- 8-bromo-6-chlorochromones

[reaction: see text] An efficient synthetic route to Cbz-protected 3-aminomethyl-2-aryl-8-bromo-6-chlorochromones has been developed. 3-Aryl-1-(3-bromo-5-chloro-2-hydroxyphenyl)-2-propen-1-one or 2-aryl-8-bromo-6-chlorochroman-4-one could be reacted under Mannich conditions yielding 2-aryl-8-bromo-6-chloro-3-methylenechroman-4-one, which was further converted to the target compound via an aza-Michael reaction followed by an SeO(2) oxidation. This procedure represents a new method to introduce a primary aminomethyl group at the 3-position of a 2-arylchromone scaffold. The Cbz-protected 3-aminomethyl-2-aryl-8-bromo-6-chlorochromones can, e.g., be used in the synthesis of chromone-based beta-turn peptidomimetics.     

Five-Membered 2,3-Dioxo Heterocycles: XLV. Thermolysis of 5-Aryl-4-phenyl-2,3-dihydrofuran-2,3-diones in the Absence of Other Partners and in the Presence of Carbonyl Compounds

Aroyl(phenyl)ketenes generated by thermolysis of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones undergo [4+2]-cyclodimerization to 3-aroyl-6-aryl-3,5-diphenyl-3,4-dihydro-2H-pyran-2,4-diones. Heating of the latter leads to rearrangement with formation of 4-aroyloxy-6-aryl-3,5-diphenyl-2H-pyran-2-ones. Thermolysis of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones in the presence of carbonyl compounds yields 6-aryl-5-phenyl-4H-1,3-dioxin-4-ones.     

Hetero-diels-alder reaction of N-cyanoaniline and pyridinium cyano-(ethoxycarbonyl)methylide with aroylketenes generated in situ in thermolysis of 6-aryl-2,2-dimethyl-1,3-dioxin-4-ones

We have used thermolysis of 6-aryl-2,2-dimethyl-1,3-dioxin-4-ones in the presence of N-cyanoaniline, pyridinium cyano(ethoxycarbonyl)methylide, and 4-hydroxybenzonitrile to obtain the corresponding 6-aryl-2-phenylamino-1,3-oxazin-4-ones, pyridinium ethoxycarbonyl(4-oxo-6-aryl-4H-1,3-oxazin-2-yl)methylides, and p-cyanophenyl esters of 3-aryl-3-oxopropanoic acids. We present the results of a preliminary investigation of the biological activity of these compounds. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 764–768, May, 2006.     

Synthesis of annelated [a]aza-anthracenones and thieno[3,2-g]aza-naphthalenones through ring transformation of 2H-pyran-2-one followed by photocyclization

A concise synthesis of some new classes of heterocycles (4-aryl-11-oxo-1,2,3,11-tetrahydro-1,3a-diaza-cyclopenta[a]anthracen-6-carbonitriles and 5-aryl-12-oxo-1,3,4,12-tetrahydro-2H-1,4a-diazabenzo[a]anthracene-7-carbonitriles) has been developed by the ring transformation of suitably functionalized 2H-pyran-2-one with α-oxoketene cyclic aminals to intermediates (8-aroyl-5-aryl-2,3-dihydro-1H-imidazo[1,2-a]pyridine-7-ylidene)-acetonitriles and (9-aroyl-6-aryl-1,2,3,4-tetrahydropyrido[1,2-a]pyrimidin-8-ylidene)-acetonitriles) followed by their photocyclization either in CHCl₃ or acetonitrile. This reaction was further explored for the synthesis of methyl 4-aryl-11-oxo-1,2,3,11-tetrahydro-1,3a,9-triaza-cyclopenta[a]anthracene-6-carboxylate, 4-aryl-11-oxo-1,2,3,11-tetrahydro-1,3a,9-triaza-cyclopenta[a]anthracene-6-carbonitriles, 5-aryl-12-oxo-1,3,4,12-tetrahydro-2H-1,4a,10-triazabenzo[a]anthracene-7-carbonitriles, 4-aryl-10-oxo-1,2,3,10-tetrahydro-9-thia-1,3a-diazadicyclopenta[a,g]naphthalene-6-carbonitriles and 5-aryl-11-oxo-1,3,4,11-tetrahydro-2H-10-thia-1,4a-diazacyclopenta[b]phenanthrene-7-carbonitriles from the similar reactions.     

Synthesis of 4,6-diaryl-1-benzyl-6-hydroxy-5,5-dimethyl-2-oxopiperidine-3-carbonitriles and their analogs via a modified Reformatsky reaction

Organozinc compounds obtained from 1-aryl-2-bromo-2-methylpropanone and zinc react with N-benzyl-3-aryl-2-cyanoacrylamides or N-[6-(2-cyano-1-oxo-3-phenylprop-2-enylamino)hexyl]-2-cyano-3-phenylacrylamide to give 4,6-diaryl-1-benzyl-6-hydroxy-5,5-dimethyl-2-oxopiperidine-3-carbonitriles or 1,6-bis(6-aryl-3-cyano-6-hydroxy-5,5-dimethyl-2-oxo-4-phenylpiperidyl)hexanes as a single isomer with trans-located piperidine hydrogen atoms.     

Synthesis of alkyl hexahydropyrazino-[1,2-<Emphasis Type="Italic">c</Emphasis>]pyrimidine-9-carboxylates

Cyclocondensation of 3-alkoxycarbonylmethylidenepiperazin-2-ones with α-chlorobenzyl isocyanates gave alkyl 8-aryl-1,6-dioxo-1,3,4,6,7,8-hexahydro-2H-pyrazino[1,2-c]pyrimidine-9-carboxylates. The use of 1-aryl-2,2,2-trifluoroethyl isocyanates in an analogous cyclization gave 6-aryl-1,8-dioxo-6-trifluoromethyl-1,3,4,6,7,8-hexahydro-2H-pyrazino[1,2-c]pyrimidine-9-carboxylates.     

Synthesis of polyheterocyclic compounds derived from 6-amino- 4-aryl-2-r-4h-furo[2,3-<Emphasis Type="Italic">b</Emphasis>]pyran-5-carbonitriles

Syntheses were developed for 4-aryl-6-ethoxy-2-R-furo[2,3-b]pyridine-5-carbonitriles and ethyl esters of 5-amino-4-aryl-7-methyl-2-R-1,9-dioxa-8-azacyclopenta[b]naphthalene-6-carboxylic acids based on the reaction of 6-amino-4-aryl-2-R-4H-furo[2,3-b]pyran-5-carbonitriles with ethyl acetoacetate and nucleophilic recyclization. The mechanisms of these reactions are considered.     

Reactions of zinc enolates derived from 1-aryl-2-bromo-2-phenylethanone and 2-bromoindan-1-one with alkyl 2-oxochromene-and 6-bromo-2-oxochromene-3-carboxylates

Zinc enolates derived from 1-aryl-2-bromo-2-phenylethanone react with alkyl 2-oxochromene-3-carboxylates and methyl 6-bromo-2-oxochromene-3-carboxylate to give, respectively, alkyl 4-(2-aryl-2-oxo-1-phenylethyl)-2-oxochroman-3-carboxylates and methyl 6-bromo-4-(2-aryl-2-oxo-1-phenylethyl)-2-oxochroman-3-carboxylate as a single stereoisomer. Zinc enolates derived from 2-bromoindan-1-one react with alkyl 2-oxochromene-3-carboxylates to give alkyl 2-oxo-4-(1-oxoindan-2-yl)chroman-3-carboxylates as a single stereoisomer.     

A novel and efficient synthesis of pyrazolo[3,4-d]pyrimidine derivatives and the study of their anti-bacterial activity

In this work 4-amino-6-aryl-2-phenyl pyrimidine-5-carbonitrile derivatives were synthesized through a one-pot,three-component reaction of an aldehyde,malononitrile and benzamidine hydrochloride,in the presence of magnetic nano Fe₃O₄ particles as a catalyst under solvent-free conditions.3-Amino-6-aryl- 2-phenylpyrazolo[3,4-d]pyrimidine derivatives were prepared through an efficient and environmentally friendly reaction between 4-amino-6-aryl-2-phenylpyrimidine-5-carbonitrile derivatives and hydrazine hydrate and their antibacterial activity has been evaluated.     

Reformatsky reaction of methyl 1-bromocyclohexane-1-carboxylate with N-aryl-2-oxochromene-3-carboxamides

Reformatsky reagent generated from methyl 1-bromocyclohexane-1-carboxylate reacted with N-aryl-2-oxochromene-3-carboxamides and N-aryl-6-bromo-2-oxochromene-3-carboxamides to give, depending on the conditions, the corresponding N-aryl-(6-bromo)-4-(1-methoxycarbonylcyclohexyl)-2-oxochroman-3-carboxamides or 3-aryl-(9-bromo)-1,1-pentamethylene-2,3,4,4a,5,10b-hexahydro-1H-chromeno[3,4-c]pyridine-2,4,5-triones. The products were isolated as a single diastereoisomer.     

Synthesis and Spectral Characterization of Some Novel Thiazolyl-Pyrazoline Derivatives Containing 1,2,3-Triazole Moiety

Abstract

A series of novel 3-aryl-5-(2-aryl-1,2,3-triazol-4-yl)-1-(4-aryl-2-thiazoyl)-pyrazolines 6a–6r were synthesized using 2-aryl-4-formyl-1,2,3-triazoles 1a,b as the starting materials. Thus, reacting 1a,b with 1-arylethanones 2a–2c gave 1-aryl-3-(2-aryl-1,2,3-triazol-4-yl)-2-propen-1-ones 3a–3f. The reaction of the latter with thiosemicarbazide afforded 3-aryl-5-(2-aryl-1,2,3-triazol-4-yl)-1-thiocarbamoyl-pyrazolines 4a–4f, which condensed with 2-bromo-1-arylethanones 5a–5c to afford the target compounds 6a–6r. The chemical structures of the compounds were verified by means of their IR, ¹H NMR, ESI-MS spectroscopic data, and elemental analysis.

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GRAPHICAL ABSTRACT     

Cyclization reactions of nitrils. 29. Regioselective synthesis of 6-aryl-3-cyano-2(1H)-pyridinethiones and the corresponding selenones and their characteristics

The condensation of cyanothio- and cyanoselenoacetamide with 3-aryl-3-oxo-1-piperidino-1-propene or sodium 3-aryl-3-oxo-1-propen-1-olate takes place regioselectively with the formation of the 6-aryl-3-cyano-2(1H)-pyridinethiones or the corresponding selenones. Thieno[2,3-b]pyridines, thiazolo[3,2-a]pyridinium salts, and other annellated heterocycles were obtained from the 6-aryl-3-cyano-2(1H)-pyridinethiones.For Communication 28, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 805–812, June, 1988.     

Regioselective arylation of 3-bromopyridine

The addition of aryl Grignard reagents to the 1-phenoxycarbonyl salt of 3-bromopyridine affords 2-aryl-5-bromo-1-phenoxycarbonyl-1,2-dihydropyridines and 4-aryl-3-bromo-1-phenoxycarbonyl-1,4-dihydropyridines. The crude dihydropyridines were aromatized with o-chloranil in refluxing toluene to give 4- and 6-aryl-3-bromopyridines. The regioselectivity of this two-step process, 6- vs. 4-substitution, was examined and found to be dependent upon the structure of the Grignard reagent. Unhindered aryl Grignard reagents, e.g., phenyl and 2-naphthyl, gave mainly 6-aryl-3-bromopyridines (49-52%) along with 9% of the 4-substituted isomer and less than 4% of the 2-aryl-3-bromopyridine. Hindered aryl Grignard reagents, e.g., o-tolyl and 1-naphthyl, are less regioselective. When a catalytic amount of cuprous iodide is present during the Grignard reaction, nearly exclusive 1,4-addition results. The crude 4-aryl-3-bromo-1,4-dihydropyridines were aromatized with p-chloranil to provide 4-aryl-3-bromopyridines in good yield and high isomeric purity. The sequential use of the cuprous iodide-catalyzed Grignard reaction and the “normal” Grignard reaction provided a regiospeci-fic synthesis of 3-bromo-6-(p-methoxyphenyl)-4-phenylpyridine from 3-bromopyridine.     

Cycloacylation of N-phenyl-N′-R-thioureas with 3-aryl-2-propenoyl chlorides

Cycloalkylation of N-phenyl-N′-R-thiourea with 3-aryl-2-propenoyl chlorides in acetone gives as products 6-aryl-3-phenyl-2-(R-imino)-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-one and their hydrochlorides. The same reaction carried out in acetone in the presence of K₂CO₃ leads to the formation of 6-aryl-3-phenyl-2-(R-imino)-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-ones, N-(3-aryl-2-propenoyl)-N-phenylthioureas, 3-aryl-2-propenoylanilides, and phenyl isothiocyanate.     

Synthesis of 4-Aryl-6-oxo-5-cyano-1,6-dihydropyridine-2-carboxylic Acids and Their Methyl Esters by Reacting Methyl Acylpyruvates with Malononitrile and Cyanoacetamide

Russian Journal of General Chemistry - A series of new methyl 4-aryl-6-oxo-5-cyano-1,6-dihydropyridine-2-carboxylates and 4-aryl-6-oxo-5-cyano-1,6-dihydropyridine-2-carboxylic acids were...     

Cycloacylation of <Emphasis Type="Italic">N</Emphasis>-Phenyl-3-oxobutanethioamide with 3-Aryl-2-propenoyl Chlorides

Reactions of N-phenyl-3-oxobutanethioamide with 3-aryl-2-propenoyl chlorides in acetone in the presence of potassium carbonate give rise to 4-aryl-5-acetyl-1-phenyl-6-thioxopiperidin-2-ones, 2-aryl-5-acetyl-6-phenylamino-2,3-dihydro-4H-thiopyran-4-ones, and 6-aryl-2-acetonylidene-3-phenyl-5,6-dihydro-4H-1,3-thiazin-4-ones whose structure was proved both by spectral methods and chemical transformations.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 292–296.Original Russian Text Copyright © 2005 by Britsun, Borisevich, Samoilenko, Lozinskii.     

Synthesis of substituted methyl 5,5-polymethylene-2,4-dioxotetrahydropyran-3-carboxylates

Dimethyl 2-(1-bromocyclohexylcarbonyl)-, 2-(1-bromocyclopentylcarbonyl)-, and 2-(1-bromocyclobutylcarbonyl)-2-methylmalonates reacted with zinc and aromatic aldehydes to give the corresponding methyl 1-aryl-4-methyl-3,5-dioxo-2-oxaspiro[5.5]undecane-4-, 6-aryl-9-methyl-8,10-dioxo-7-oxaspiro[4.5]-decane-9-, and 5-aryl-8-methyl-7,9-dioxo-6-oxaspiro[3.5]nonane-8-carboxylates.     

Trithia- and dithiaselenapentalenes from benzylidene-1,2-dithioles and heterocumulenes

Deprotonation of the 5-aryl-3-benzyl-1λ⁴,2-dithiol-1-ylium iodides ( 6a–6d ) obtained by reaction of the 1-aryl-4-phenylbutan-1,3-diones ( 5a–5d ) with hydrogen sulfide and iodine in ethanol gave the stable 5-aryl-3-benzylidene-3H-1,2-dithioles ( 3a–3d ), respectively. The dithioles ( 3a–3d ) underwent thermal cycloaddition reactions with isoselenocyanates and isothiocyanates to give the 2-(substituted amino)-5-aryl-3-phenyl-6,6aλ⁴-dithia-1-selenapentalenes ( 7a–7h ) andthe 2-(substituted amino)-5-aryl-3-phenyl-1,6,6aλ⁴-trithiapentalenes ( 8a–8l ), respectively. The dithioles( 3a–3d ) reacted with isocyanates to give the N-substi-tuted-2-phenyl-2-(5-aryl-3H-1,2-dithiol-3-ylidene) acetamides ( 11a–11h ). © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8 : 233–244, 1997.