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The condensation of 3-arylhydrazinylidenepentane-2,4-diones with hydrazine hydrate, 2-hydroxyethylhydrazine, benzylhydrazine hydrochloride, and 4-hydrazinylbenzenesulfonamide hydrochloride gave 4-aryldiazenyl-3,5-dimethylpyrazoles. An alternative route to the synthesis of N-substituted 4-aryldiazenylpyrazoles is based on the alkylation of NH-pyrazoles with haloalkanes. The synthesized compounds were tested for antimicrobial activity against eight pathogenic dermatophytes, yeast-like fungi of the Candida genus and the bacteria Neisseria gonorrhoeae. The structure—activity relationship analysis showed that 4-tolyldiazenylpyrazoles bearing H, AcO(CH2)4, or HO(CH2)4 substituents at the N(1) atom have the highest mycostatic activity against all the dermatophyte strains under study. However, 4-aryldiazenyl-3,5-dimethylpyrazoles proved to be quite cytotoxic against the McCoy B cell line.

Fluorine-containing analogues of non-steroidal antiinflammatory drugs Tribuzone and Ketazone have been synthesized by reaction of 1,2-diphenylpyrazolidine-3,5-dione with polyfluoroalkyl-containing 3- and 2-oxo esters. Ethyl 3-(pyrazolidin-4-yl)-3-(polyfluoroalkyl)prop-2-enoates have been obtained as Knoevenagel reaction products from 3-oxo esters in the presence of l-proline. Unlike with 3-oxo esters, addition of ethyl 3,3,3-trifluoro-2-oxopropanoate under basic conditions afforded ethyl 2-(pyrazolidin-4-yl)-3,3,3-trifluoro-2-hydroxypropanoate or its salt without elimination of a water molecule.

The alkylation of 6-(polyfluoro)alkyl-2-thiouracils with 4-bromobutyl acetate in refluxing acetonitrile in the presence of K2CO3 proceeds regioselectively to give S, O-disubstituted pyrimidines as the major products and S,N-isomers as the minor ones, whereas the use of 2-bromoacetophenone as an alkylating agent results in the formation of the S,O-isomer. 6-Trifluoromethyl-2-thiouracil and 2-(2-oxo-2-phenylethylthio)-4-(2-oxo-2-phenylethoxy)-6-trifluoromethyl-pyrimidine exhibited marked tuberculostatic activity. 6-Trifluoromethyl-2-thiouracil did not exert a significant cytotoxic effect on the HeLa cell culture and human dermal fibroblasts.

The structure of 6-polyfluoroalkyl-2-thiouracils and reactivity of nucleophilic centers in their molecules were analyzed by quantum chemical calculations. According to the experimental data, methylation of 6-polyfluoroalkyl-2-thiouracils with methyl iodide initially gives 2-methylsulfanyl-substituted pyrimidin-4-one and then S,N3- and S,O-dimethyl derivatives. The optimal conditions for the selective formation of the S, N3- isomer were heating in tert-butyl alcohol in the presence of cesium carbonate as a base. Ethylation of 6-polyfluoroalkyl-2-thiouracils afforded approximately equal amounts of S,N3- and S,O-dimethyl derivatives. S,N3-Dimethyl-substituted pyrimidines in boiling ethanol in the presence of potassium carbonate were converted into uracil potassium salts as a result of nucleophilic substitution of the methylsulfanyl group by ethoxy and subsequent dealkylation of the latter.

Найдены конкурентные пути трехкомпонентной циклизации полифторалкил-3-оксоэфиров и метилкетонов с 3-амино-1-пропанолом в зависимости от условий. Показано, что в 1,4-диоксане реакции приводят к гексагидро- пиридо-[2,1-b][1,3]-оксазин-6-онам, а в этаноле к – циклогекс-2-ен-1-онам.редложен механизм превращений полифторалкил-3-оксоэфиров и метилкетонов с 3-амино-1-пропанолом.

Refluxing of polyfluoroalkyl-containing 2-(arylhydrazinylidene)-1,3-diketones in dichloroalkanes in the presence of TiCl4 gives 3-acyl-4-polyfluoroalkylcinnolines as a result of Friedel-Crafts intramolecular cyclization with the participation of polyfluoroacyl and arylhydrazone moieties. 2-(Arylhydrazinylidene)-3-phenyl-1-polyfluoroalkylpropan-1,3-diones in the presence of CF3SO3H in dichloromethane at −20…−30 °C undergo the competitive cyclization with the participation of polyfluoroacyl and benzoyl groups to form 3-hydroxy-2-(arylhydrazinylidene)-3-polyfluoroalkylindan-1-ones. The heating of 2-(arylhydrazinylidene)-1,3-diketones in polyphosphoric acid at 115…120 °C resulted in 2-polyfluoroalkyl-1-(2-arylhydrazinylidene)ethan-2-ones. The tuberculostatic activity of the obtained cinnolines and indanone was found to be at the level of pyrazinamide or higher. It was established that these compounds do not inhibit cholinesterases and have rather weak inhibitory activity against carboxylesterase. A high antiradical activity was shown for indanone.

The alkylation of ambident anions of 2-(methylsulfanyl)-6-(polyfluoroalkyl)pyrimidin-4(3H)-ones with 4-bromobutyl acetate leads to concurrent formation of O- and N-(4-acetoxybutyl) derivatives. Polar aprotic solvents favor formation of the O-isomer, and weakly polar dioxane favors N-alkylation. The reaction of 2-(methylsulfanyl)-6-(trifluoromethyl)pyrimidin-4(3H)-one with an equimolar amount of 1,2-dibromoethane in polar acetonitrile gives a mixture of N,N-, O,O-, and N,O-bridged bis-pyrimidines, as well as N- and O-[2-(methylsulfanyl)ethyl] derivatives, whereas in the presence of 10 equiv of 1,2-dibromoethane the N,O-isomer is formed as the only product. The reaction in weakly polar tetrahydrofuran yields N,N- and N,O-bispyrimidines.

A series of 2-arylhydrazinylidene-3-oxo-4,4,4-trifluorobutanoic acids was synthesized via dealkylation of ethyl 2-arylhydrazinylidene-3-oxo-4,4,4-trifluorobutanoates under the action of a Lewis acid. Under the same conditions, ethyl 2-arylhydrazinylidene-3-oxobutanoates were also found to undergo dealkylation rather than the previously described cyclization into cinnolones. Study of the esterase profile of these compounds showed that trifluoromethyl-containing acids, in contrast to non-fluorinated analogs, were effective and selective inhibitors of carboxylesterase (CES), without substantially inhibiting structurally related cholinesterases (acetylcholinesterase and butyrylcholinesterase). Moreover, both 3-oxo-4,4,4-trifluorobutanoic and 3-oxobutanoic acids having methyl or methoxy substituent in the arylhydrazinylidene fragment showed high antioxidant activity in the ABTS test. Thus, 2-arylhydrazinylidene-3-oxo-4,4,4-trifluorobutanoic acids were found to constitute a new class of effective and selective CES inhibitors that also possess high radical-scavenging activity.

A new one-pot reaction between polyfluoroalkylated 3-oxo esters, methyl ketones and primary or secondary alkyl amines is reported as an efficient approach to 3-alkylamino-5-hydroxy-5-polyfluoroalkylcyclohex-2-en-1-ones. The scope of three-component cyclization and its plausible mechanism are discussed. The described protocol makes it possible to vary the functional substituents in 2, 3 and 5 positions of carbocycles. Anhydrous conditions are necessary for the productive synthesis of aminocyclohexenones, whereas in the presence of water the competitive formation of alkyl ammonium salts of keto hydroxy carboxylates is observed. Dehydration of the aminocyclohexenones was effectively used for the synthesis of 3-alkylamino-5-trifluoromethylphenols, some of which exhibited moderate antifungal activities against eight pathogenic fungal strains.

A one-pot three-component reactions between polyfluoroalkylated 3-oxo esters and methyl ketones with 1,3-diaminopropane result in 8-hydroxy-9a-alkyl(phenyl)-8-(polyfluoroalkyl)octahydro-6H-pyrido[1,2-a]pyrimidin-6-ones, whereas a similar reaction with 1,4-diaminobutane forms a salt with trifluoroacetoacetic ester. In a two-component reaction, diamines with a long aliphatic chain (1,4-diaminobutane, 1,6-diaminohexane and 1,8-diaminooctane) react with an aldol derived from trifluoroacetoacetic ester and acetone, to give bis-cyclohexenones having an aliphatic linker. Using 2-(aminomethyl)aniline in a three-component reaction with polyfluoroalkyl-3-oxo esters leads to new 7-hydroxy-5a-alkyl(phenyl)-7-(polyfluoroalkyl)-5a,6,7,8-tetrahydro-5H-pyrido[2,1-b]quinazolin-9(11H)-ones. Regioisomeric and spatial structures of new heterocycles were studied, and the mechanism of their formation was proposed. Some synthesized heterocycles were found to have moderate antiviral activity against influenza A/Puerto Rico/8/34 (H1N1) and Coxsackie B3 viruses.

The review is focused on the synthesis of fluoroalkyl-containing heteroannulated pyrimidines via the reactions of alkyl 3-oxo-3-polyfluoroalkylpropionates and their ethoxymethylidene and 2-arylmethylidene derivatives with hetarylamines. Heteroannulation of polyfluoroalkyl-containing pyrimidines is also discussed.

The antituberculosis activity of dihydrotriazolo[5,1-c][1,2,4]triazines, dihydropyrazolo[5,1-c][1,2,4]triazines, dihydroimidazolo[5,1-c][1,2,4]triazines, and dihydrotetrazolo[5,1-c][1,2,4]triazines was studied. A synthetic method for convenient synthons, 3-amino-1,2,4-triazines, was proposed. Their tuberculostatic activity was investigated.

We have optimized the reaction conditions for the synthesis of 2-methylsulfanyl-6-polyfluoro-alkylpyrimidin-4-ones. In particular the yield of trifluoromethyl-substituted heterocycle was increased to 96%, and new polyfluoroalkyl-substituted analogs were prepared. The interaction of these heterocycles with morpholine or hydrazine was shown to result in nucleophilic substitution of the methylsulfanyl group, leading to 2-morpholino- and 2-hydrazino-6-polyfluoroalkylpyrimidin-4-ones. The reaction of 2-(2-phenylhydrazino)-6-trifluoromethylpyrimidin-4-one with paraform produced 5-oxo-2-phenyl-7-tri-fluoromethyl-5H-1,2,4-triazolo[4,3-а]pyrimidin-1-id-2-ium. The lactam structure of the synthesized heterocycles was established by X-ray structural analysis, as well as by IR and NMR spectroscopy.

8-Polyfluoroalkylpyrimido[2,1-b][1,3,5]thiadiazine-6-ones containing a structural fragment of amino acid or its ester were synthesized by a multicomponent cyclization of 6-polyfluoroalkyl-2-thiouracils with formaldehyde and amines. The use of diamino acids allowed the preparation of bis(pyrimido-[2,1-b][1,3,5]thiadiazin-6-ones), containing an aliphatic linker with a carboxy group. Two of the synthesized compounds exhibited weak antituberculosis activity in vitro.

A multi-component double Mannich cyclocondensation of 6-polyfluoroalkyl-2-thiouracils with formalin and heterocyclic amines (2-aminopyridine, 2-aminopyrimidine, 4-aminoantipyrine) proceeded regiospecifically at the C=S and NH centers giving rise to 3-hetaryl-8-polyfluoroalkylpyrimido[2,1-b][1,3,5]thiadiazines. The regioisomeric structure of the products was established by X-ray crystallography, IR and NMR spectroscopy, GLC-MS spectrometry. 6-Trifluoromethyl-2-thiouracil and 8-polyfluoroalkylpyrimido[2,1-b]thiadiazines exhibited weak tuberculostatic activity.

6-Polyfluoroalkyl-2-thiouracils react with formaldehyde and primary amines in EtOH (MeCN) at 2-mercapto and 3-amino groups to yield pyrimido[2,1-b][1,3,5]thiadiazines via the multicomponent double Mannich reaction. The structure of 3-benzyl-8-nonafluorobutyl-3,4-dihydro-2H,6H-pyrimido[2,1-b][1,3,5]thiadiazin-6-one was studied by the X-ray diffraction analysis. The use of ethylenediamine in these reactions yields 3,3′-ethane-1,2-diyl-bis(pyrimido[2,1-b]thiadiazinone) as a result of the bis-double Mannich cyclocondensation. 8-Polyfluoroalkyl-pyrimido[2,1-b]thiadiazines exhibit weak tuberculostatic activity.

Alkylation of polyfluoroalkyl-containing pyrazoles with 4-bromobutyl acetate in acetone in the presence of potassium carbonate leads to a mixture of isomeric 1-(4-acetoxybutyl)-3-fluoroalkyl- and 1-(4-acetoxybutyl)-5-fluoroalkylpyrazoles, which in a number of cases were successfully separated by HPLC. Deacylation in acidic medium with gaseous hydrogen chloride and in basic medium with gaseous ammonia leads to 1-(4-hydroxybutyl)pyrazoles, which manifest moderate tuberculostatic activity.

5-Fluoroalkyl-5-hydroxy-4-hydroxyimino-1-isonicotinoyl-4,5-dihydro-1H-pyrazoles were synthesized via a one-pot procedure from polyfluoroalkyl-containing 1,3-diketones, sodium nitrite in acetic acid, and isoniazid. Acetylacetone gave rise to 3-hydroxyiminopentane-2,4-dione monoisonicotinoylhydrazone which underwent intramolecular cyclization to 5-hydroxy-4-hydroxyimino-1-isonicotinoyl-3,5-dimethyl-4,5-dihydro-1H-pyrazole on heating in ethanol. The synthesized compounds exhibited moderate tuberculostatic activity.

The alkylation of 4-polyfluoroalkylpyrimidin-2-ones with iodomethane, 4-bromobutyl acetate, and epichlorhydrin occurs regiospecifically to form O-regioisomers.

3-Polyfluoroalkyl-1,2-dihydroquinoxalin-2-ones react with 4-bromobutyl acetate to furnish 1-(4-acetoxybutyl)quinoxalin-2-ones and 2-(4-acetoxybutoxy)quinoxalines in the ratio 2: 1. Deacylation of these compounds under acidic conditions gives the corresponding 1-(4-hydroxybutyl)- and 2-(4-hydroxybutoxy)-substituted quinoxalines. The structures of compounds synthesized were established by X-ray crystallography, IR spectroscopy, 1H and 19F NMR spectroscopy, GLC-MS.

An improved method for the synthesis of fluoroalkyl-containing 3-hydroxyimino-1,5-benzodiazepines is proposed. For this, 3-hydroxyimines were obtained via nitrosation of 1,3-diketones and 3-oxoesters by tert-butylnitrite in diethylether under acid catalysis conditions and were reacted without isolation and further purification with ortho-phenylenediamine. It was found that polyfluoroalkyl-containing 3-hydroxyimino-1,5-benzodiazepin-2-ones and 2-hydroxy-3-hydroxyimino-2-trifluoromethyl-4-phenyl-1H-1,5-benzodiazepine possess high tuberculostatic activity comparable with that of isoniazide. Tests for acute toxicity of the trifluoromethylated heterocycles showed that they are less toxic than isoniazide.

3-Trifluoromethyl-substituted 4-nitrosopyrazolines and 4-nitrosopyrazoles were prepared by a one-pot synthesis from trifluoromethyl-containing 1,3-diketones, sodium nitrite in acetic acid, and hydrazines (hydrazine hydrate, methylhydrazine). 3-Trifluoromethylpyrazolines can be converted to pyrazoles on heating. The use of phenylhydrazine in these reactions led to the formation of regioisomeric 4-hydroxyimino-5-(trifluoromethyl)pyrazoline. The structure of heterocycles synthesized was established using X-ray diffraction study, 1H and 19F NMR spectroscopy. The obtained products exhibited considerable tuberculostatic activity.

The data on the synthesis, structure and chemical transformations of 2-(het)arylhydrazono-1,3-dicarbonyl compounds is surveyed. The synthetic potential and possible applications of the title compounds are analyzed.

Steric structure of fluorinated 2-arylhydrazono-3-oxo esters was studied by 1H, 19F, and 13C NMR spectroscopy and X-ray analysis. It was found that these compounds in the crystalline state and in solutions in acetone-d6, DMSO-d6, and CDCl3 exist as Z isomers with the ester fragment involved in intramolecular hydrogen bond with the hydrazone NH proton. Exceptions are alkyl 2-arylhydrazono-4,4-difluoro-3-oxobutanoates which exist in acetone-d6 as mixtures of Z and E isomers, the former prevailing. Unlike fluorinated analogs, ethyl 2-(4-methylphenyl)hydrazono-3-oxobutanoate in crystal has the structure of E isomer in which intramolecular hydrogen bond is formed between the NH proton and acetyl carbonyl group. The same compound in acetone-d6, DMSO-d6, and CDCl3 gives rise to a mixture of Z and E isomers, the latter prevailing.

New fluoroalkyl-containing 2,2′-(biphenyl-4,4′-diyldihydrazono)bis(1,3-diketones) and 2,2′-(biphenyl-4,4′-diyldihydrazono)bis(3-oxopropionates) were synthesized by azo coupling of the corresponding 1,3-dicarbonyl compounds with biphenyl-4,4′-bis(diazonium) dichloride. Complexing ability of the obtained bis-hydrazones was studied, and new coordination compounds of the general formula M2L2 [where M = Ni(II), Cu(II); L = fluoroalkyl-containing 2,2′-(biphenyl-4,4′-diyldihydrazono)bis(1,3-diketone)] were obtained.

According to the 1H, 13C, and 19F NMR data, fluoroalkyl-containing 1,2,3-trione 2-arylhydrazones in CDCl3 exist exclusively, while in (CD3)2CO preferentially, as isomers in which the acyl or aroyl group is involved in intramolecular hydrogen bond. The isomer structure was assigned on the basis of the chemical shifts of the carbonyl carbon atoms and fluorine atoms and carbon-fluorine spin-spin coupling constants JC-F. X-Ray diffraction data showed that 1,2,3-trione 2-arylhydrazones in crystal have the same structure as in CDCl3 solution. Quantum-chemical calculations were performed to rationalize predominant formation of 1,2,3-trione 2-arylhydrazone isomers with a free polyfluoroacyl group.

The crystal structures of the chelates NiIIL (L2− are the N,N′-(o-phenylene)-bis[4-(4-methylphenyl)hydrazono-3-oxo-1,1,2,2-tetrafluorononane-5-iminate], N,N′-ethylene-bis[3-(4-methylphenyl)hydrazono-4-oxo-5,5,6,6,7,7,8,8-octafluorooctane-2-iminate], or N,N′-ethylene-bis(4-hydroxy-5,5,6,6,7,7,8,8-octafluoro-3-octene-2-iminate) anions) were studied by X-ray diffraction. Magnetic measurements and ESR spectroscopic studies revealed the appearance of paramagnetism due to a tetrahedral distortion of the coordination unit and also the unusual behavior of the effective magnetic moment at low temperatures.

by a multicomponent cyclization of 6-polyfluoroalkyl-2-thiouracils with formaldehyde and amine or amino acids, respectively

1,2,3-Triketone 2-(antipyrin-4-yl)hydrazones were synthesized via the azo-coupling reactions of 1,3-diketones with 2-(antipyrin-4-yl)diazonium chloride. The fluoroalkyl-containing hetarylhydrazone enters into cyclocondensation with hydrazines at the 1,3-dicarbonyl fragment to yield 3-tetrafluoroethyl derivatives of pyrazole. It was found that 1,2,3-triketone 2-(antipyrin-4-yl)hydrazones and N-(2-hydroxyethyl)-substituted pyrazole exhibit analgesic activity comparable with that of their structural analog analgin (metamizole sodium), but do not possess antipyretic properties. In contrast, N-phenyl-substituted pyrazole did not exhibit analgesic properties but produced a certain antipyretic effect four hours after pyrogenic administration. Fluoroalkyl-containing compounds are less toxic substances than nonfluorinated 2-(antipyrin-4-yl)hydrazone and analgin.

The coupling of trifluoromethylated 1,3-diketones with (het)aryldiazonium chlorides results mainly in the formation of 1,2,3-triketones 2-(het)arylhydrazones while using hetarylamine with a NH-group at the α-position of the heterocycle as the diazonium component gives 4,7-dihydroazolo[5,1-c]triazines due to cyclization at the trifluoroacetyl fragment. Trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones and 7-hydroxy-4,7-dihydroazolo[5,1-c]triazines react regio-selectively with methyl hydrazine and phenyl hydrazine to form 3-CF3-pyrazoles. The long-range coupling constants (JF-H) of 1-methylpyrazoles and the chemical shifts of trifluoromethyl groups in the 19F NMR spectra can be used for the determination of regio-isomeric structures of mono(trifluoromethyl)-substituted pyrazoles. 2-(Het)arylhydrazones and 4,7-dihydroazolo[5,1-c]triazines with two trifluoromethyl substituents afford the mixtures of cis- and trans-azopyrazoles in the reactions with hydrazines.

Fluoroalkyl-containing 1,2,3-triketone 2-(2,3-dimethyl-5-oxo-1-phenyl-1,2-dihydropyrazol-4-yl)-, 2-(4-ethoxycarbonylpyrazol-3-yl)-, and 2-(1,2,4-triazol-3-yl)hydrazones were synthesized by the azo coupling reactions of fluorinated 1,3-diketones with the corresponding hetaryldiazonium chlorides. The hetarylhydrazones thus synthesized were subjected to cyclocondensation with hydrazines at the 1,3-dicarbonyl fragment to give 3-fluoroalkyl-4-hetarylazopyrazoles.

2-Arylhydrazono-3-fluoroaklyl-3-oxo esters react with o-phenylenediamine under neutral conditions to form mainly o-aminoanilides, from which can be obtained 1,5-benzodiazepin-2-ones. Ethyl-2-(benzimidazol-2-yl)-2-(4-methylphenyl)hydrazonoethanoate was isolated also from the reaction of di(tri)fluoromethyl-containing 2-arylhydrazono-3-oxo esters. The reactions of o-phenylenediamine with 1,2,3-triketone 2-arylhydrazones containing alkyl substituents result in the formation of 1-(benzimidazol-2-yl)-1,2-dioxoalkane arylhydrazones, whereas phenylsubstituted analogues afford 2-phenylbenzimidazole. Nickel(II) chelates of N,N′-phenylene-bis(2-arylazo-1,3-aminovinylketones) were obtained from 1,2,3-triketone 2-arylhydrazones and o-phenylenediamine using a template method.

Acyclic N , N ′-(poly)ethylene- bis (2-arylazo-1,3-aminovinylketones) are the main products in the reactions of fluoroalkyl-containing 2-arylhydrazono-1,3-diketones with ethylenediamine, diethylenetriamine and triethylenetetramine. Nickel(II) and copper(II) chelates were obtained from N , N ′-ethylene- bis (2-arylazo-1,3-aminovinylketones). 2-Arylhydrazono-3-fluoroacyl esters formed N , N ′-ethylenediamides of 2-arylhydrazono-3-fluoroacylpropionic acids with ethylenediamine. Interaction of 2-arylhydrazono-3-fluoroacyl esters with diethylenetriamine and triethylenetetramine resulted in and decomposition products.

2-Arylhydrazono-1,3-diketones react with ethylenediamine to give, depending on the substituents, dihydro-1,4-diazepine derivative or N,N'-ethylenebis(1,3-aminovinyl ketones). Treatment of the latter with nickel(II) or copper(II) acetate results in formation of the corresponding metal chelates. Nickel complexes of N,N'-ethylenebis(1,3-aminovinyl ketones) can also be synthesized from 2-arylhydrazono-1,3-diketones and ethylenediamine on a metal template. Reactions of 2-arylhydrazono-3-oxo esters with ethylenediamine yield N,N'-ethylenebis(3-alkyl-2-arylhydrazono-3-oxopropionamides). Ethyl 2-arylhydrazonoacetoacetate reacts with ethylenediamine under mild conditions, affording ethyl 2-p-tolylazo-3-[2-(2-p-tolylhydrazono-1,3-dioxobutylamino)ethylamino]-2-butenoate.

Multi-component double Mannich cyclocondensation of 6-polyfluoroalkylthiouracils (III) with formalin and heterocyclic amines provides regiospecifically 3-hetaryl-8-polyfluoroalkylpyrimidothiadiazines (VI) (7 examples).

The data on the synthesis, structure and chemical transformations of 2-(het)arylhydrazono-1,3-dicarbonyl compounds is surveyed. The synthetic potential and possible applications of the title compounds are analyzed.

A convenient procedure has been developed for the synthesis of fluoroalkyl-substituted 6-aryl-4-hydroxy-2-oxo-(thioxo)hexahydropyrimidine derivatives by three-component condensation of fluorinated β-dicarbonyl compounds with aromatic aldehydes and urea or thiourea in the absence of a solvent using 6 mol % of 1-butyl-3-methylimidazolium tetrafluoroborate as catalyst.

4-Polyfluoroalkyl 2,4-dioxobutanoates react with aromatic aldehydes to give 4-aryl-2,6-dihydroxy-2,6-di (fluoroalkyl)-3,5-diethoxalyltetrahydropyrans 3a,b, whereas the reaction of 4-pentafluorobenzoyl 2,4-dioxobutanoate with benzaldehyde gives 5,6,7,8-tetrafluoro-1-phenyl-1 H -furo[3,4- b ]chromene-3,9-dione 4.

Polyfluorinated 2-arylhydrazono-3-oxocarboxylic acid esters react with o-phenylenediamine in neutral medium to give mainly the corresponding o-aminoanilides which can be converted into 1,5-benzodi-azepin-2-ones. In the reactions with ethyl 2-arylhydrazono-3-oxobutanoate and its 4,4-di- and 4,4,4-trifluoro derivatives, ethyl 2-(2-benzimidazolyl)-2-[(4-methylphenyl)hydrazono]ethanoate is also formed.

The reactions of o-phenylenediamine with 1,2,3-triketone 2-arylhydrazones containing alkyl substituents result in the predominant formation of 1-(benzimidazol-2-yl)-1,2-dioxoalkane arylhydrazones, whereas phenyl-substituted analogues afford 2-phenyl-benzimidazole.

7-Fluoroalkyl-4,7-dihydroazolo[5,1-c][1,2,4]triazines react with hydrazides and thiosemicarbazide to form 5-(5-hydroxy-5-polyfluoroalkyl-2-pyrazoline-4-ylhydrazono)azoles as a result of triazine ring opening at bond C-7-N-8 and followed by regio-selective condensation.