Synthesis, antiamoebic activity and thermal study of copper complexes of 1-formyl-2-pyrazolines

Copper complexes of 1-formyl-2-pyrazolines were prepared by the reaction of 1-formyl-2-pyrazolines with copper chloride and nitrate with methanol. The structures of copper complexes 1a–3a have been established by elemental analysis, FT-IR, UV and thermogravimetric analysis. These compounds were tested against HM1:IMSS strain of Entamoeba histolytica by the microdilution method. Complexes 2a and 3a are more active than other complexes.     

Pyridinethiones. VIII. The aldol and wittig condensations of 3-formyl-2(1H)-pyridones, -thiones and -selones. Preparation of new cyanopyridones

Condensations of 1-substituted-3-formyl-2(1H)-pyridones, -thiones and -selones with methyl ketones such as acetophenone give the corresponding chalcones in high yields. Geometry at the vinyl hydrogens is E. These chalcones can be cyclized with ethyl cyanoacetate in the presence of ammonium acetate to form new 3-cyano-2(1H)-pyridones. An effective “one-pot” preparation is worked out and an intermediate from the cyclization reaction is isolated. Via the Wittig reaction it is possible to prepare condensation products from 1-substituted-3-formyl-2(1H)-pyridinethiones and -selones with mainly Z geometry at the vinyl hydrogens.     

Synthesis of chalcone analogs and derivatives of 2-pyrazoline from 3-formylindole

By the crotonic condensation in an alkaline medium of 3-formylindole with various aromatic and heterocyclic methyl ketones, and also with cyclopentanone, cyclohexanone, and 1,4-diacetylbenzene, we have synthesized nineteen ,-unsaturated ketones. The majority of them were characterized as the 2,4-dinitrophenylhydrazones, the absorption maxima of which in chloroform are given. Some considerations are expressed concerning the reactivity of 3-formyl- and 3-acetylindoles. Ten 3-aryl-1-phenyl-5-(indol-3-yl)-2-pyrazolines and their analogs with a 3-heterocyclic residue have been synthesized by the reaction of 3-aryl-1-(indol-3-yl)propen-3-ones and the corresponding analogs with phenylhydrazine. Some of the compounds synthesized possess a bright luminescence.     

Pyridinethiones. IX preparation of ricinidine,thioricinidine and other 2(1H)-pyridones and -thiones related to nicotinic acid

2(1H)-Pyridones and -thiones related to 1-substituted nicotinic acid derivatives have been prepared via the corresponding l-substituted-3-formyl-2(1H)-pyridones and -thiones. A number of synthetic procedures for the interconversion of functional groups in these nicotinic acid derivatives are given i.e. preparation of the aldoximes, nitriles, carboxamides and carboxylic acids as well as the 3- hydroxyalkyl derivatives. The course of the basic peroxide oxidation of the l-substituted-3-formyl-2(1H)-pyridinethiones is found to be very dependent upon the electronegativity of the 1-substituent. A preparation of ricinidine is also described.     

Cycloadditions of diazoesters to α,β-unsaturated aldehydes

The reaction of α,β-unsturated aldehydes with diazoesters primarily gives unstable 1,3-dipolar adducts (1-pyrazolines) which evolve according to their substitution pattern: whenever there is a proton geminal to the formyl group, conjugation with the latter is highly favoured, yielding 3-formyl-2-pyrazolines which subsequently polymerize. On the other hand, if no proton is available for conjugation with the formyl group, two competitive reactions take place: tautomerisation into an ester conjugated pyrazoline and loss of nitrogen with formation of cyclopropanes, the latter reactionnal pathway being favoured with electronwithdrawing substituents.     

Synthesis of unsaturated ketones and derivatives of 2-pyrazoline containing an indole nucleus

The crotonic condensation of 3-acetylindole, its N-methyl derivative, 3-formyl-1-methylindole, and 3-formyl-6-nitroindole with various aldehydes and methyl ketones in an alkaline medium has yielded a number of unsaturated ketones, some of which have been characterized as their 2, 4-dinitrophenylhydrazones. The reaction of some of these unsaturated ketones with phenylhydrazine has yielded derivatives of 1-phenyl-2-pyrazoline, which possess luminescent properties.     

1-Thiocarbamoyl(ferrocenyl)-4,5-dihydropyrazoles

Thiosemicarbazide reacts with aryl -ferrocenylvinyl ketones and -arylvinyl ferrocenyl ketones in the presence of Bu^tOK to give 1-thiocarbamoyl-5- and -3-ferrocenyl-4,5-dihydropyrazoles, respectively. The complexes of 3-ferrocenyl-5-phenyl-, 3,5-diferrocenyl-, and 3-ferrocenyl-5-p-methoxyphenyl-1-thiocarbamoyl-4,5-dihydropyrazoles with Cu^II are described.     

Reaction of Isocyanates and Isothiocyanates with Butyraldazine; Formation of 1-Substituted 2-Pyrazolines

Phenyl isothiocyanate reacts with butyraldazine in presence of acidic catalysts to form a 2-pyrazoline (IV) whereas phenyl or benzyl isocyanates under similar conditions yield a mixture of the two isomeric 2-pyrazolines XIa and XII. On reaction with Ac₂O, IV gave the 1-acetyl derivative V. Reduction with LiAlH₄ led to the corresponding pyrazolidines. Reexamination of Kost's three step preparation of a 1-phenylthiocarbamoyl 2-pyrazoline [19] such as X via formic acid cyclization [18] of butyraldazine revealed that his first step product was apparently a mixture of two stereoisomeric 1-formyl-2-pyrazolines VIIIa and VIIIb. A mechanism for the formation of these pyrazolines is proposed.     

N—烃氧丙酰基四氢噻唑—2—硫酮的合成

在三聚氯氰存在下由烃氧丙酸与四氢噻唑-2-硫酮反应得到N-烃氧丙酰四氢噻哇-2-硫酮(2a-i),由2a,c-h与格氏试剂反应得到烃氧乙基苯基酮(3a,c-h).产物2a-i未见报道.     

Synthesis and Antimicrobial Evaluation of Some Chalcones and Their Derived Pyrazoles,Pyrazolines, Isoxazolines,and 5,6-Dihydropyrimidine-2-(1<Emphasis Type="Italic">H</Emphasis>)-thiones

Summary. Chalcones were synthesized by a base catalyzed Claisen-Schmidt condensation reaction. Bromination of chalcones afforded the dibromo derivatives. Monobromo derivatives could be obtained by treating the corresponding dibromochalcones with dry benzene in the presence of triethylamine. Pyrazole derivatives were obtained by refluxing of dibromochalcones with phenylhydrazine or 2,4-dinitrophenylhydrazine in dry pyridine. Chalcones were treated with hydrazine hydrate or phenyl hydrazine in ethanol to afford Δ ²-pyrazolines and N-phenyl-Δ ²-pyrazolines. Condensation of chalcones with hydroxylamine hydrochloride or thiourea in ethanolic sodium hydroxide solution gave 4,5-dihydroisoxazoles and 5,6-dihydropyrimidine-2-(1H)-thiones. The prepared compounds were tested for antimicrobial activity against four different bacterial species displaying different degrees of antibacterial activities or inhibitory actions.     

Synthesis and Antimicrobial Evaluation of Some Chalcones and Their Derived Pyrazoles, Pyrazolines, Isoxazolines, and 5,6-Dihydropyrimidine-2-(1 H )-thiones

Chalcones were synthesized by a base catalyzed Claisen-Schmidt condensation reaction. Bromination of chalcones afforded the dibromo derivatives. Monobromo derivatives could be obtained by treating the corresponding dibromochalcones with dry benzene in the presence of triethylamine. Pyrazole derivatives were obtained by refluxing of dibromochalcones with phenylhydrazine or 2,4-dinitrophenylhydrazine in dry pyridine. Chalcones were treated with hydrazine hydrate or phenyl hydrazine in ethanol to afford Δ ²-pyrazolines and N-phenyl-Δ ²-pyrazolines. Condensation of chalcones with hydroxylamine hydrochloride or thiourea in ethanolic sodium hydroxide solution gave 4,5-dihydroisoxazoles and 5,6-dihydropyrimidine-2-(1H)-thiones. The prepared compounds were tested for antimicrobial activity against four different bacterial species displaying different degrees of antibacterial activities or inhibitory actions.     

Facile Synthesis of 6-Aryl-3-cyanopyridine-2-(1H)-thiones from Aryl Ketones

An improved synthesis of 6-aryl-3-cyanopyridine-2-(1H)-thiones utilizing enaminones as starting materials catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO) was described. Moreover, a convenient one-pot conversion of aryl ketones to 6-aryl-3-cyanopyridine-2-(1H)-thiones was also developed in moderate to good yields (up to 80%).     

Synthesis of pyrazole, 1,3,4-thiadiazole,and 1,2,4-triazole derivatives by condensatoin of 1,3-dioxo compounds with thiosemicarbazide derivatives

The reaction of -diketones with 2-unsubstituted thiosemicarbazides leads to the formation of the corresponding 1-thiocarbamoyl-5-hydroxy-2-pyrazolines, which readily undergo aromatization to give pyrazoles, while the reaction of benzoylacetaldehyde leads to the formation of the corresponding hydrazone. Acetylacetone 2-methyl- and 2,4-dimethylthiosemicarbazones are inclined to undergo tautomerization and, depending on the conditions, can exist in enehydrazine, hydrazone, 1,2,4-triazoline, and 1,3,4-thiadiazoline forms or mixtures of these forms. Upon heating these substances are converted to mixtures of the 1,3,5-trimethylpyrazole and the corresponding 1,2,4-triazoline-5-thione. The structures of the compounds were studied by means of IR and ¹H, ¹³C, and ¹⁵N NMR spectroscopy and mass spectrometry.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1260–1270, September, 1990.     

Synthesis, characterization and fluorescence studies of 3,5-diaryl substituted 2-pyrazolines

A series of 2-pyrazolines have been synthesized from α, β unsaturated ketones and hydrazine hydrate with acetic/formic acid in ethanol/DMSO. The structures of 2-pyrazolines have been established by spectroscopic techniques i.e. UV, IR, (1)H NMR, (13)C NMR and micro element analysis. Fluorescence spectra were recorded in the solution at fixed concentration and same excitation wavelength at 290 nm. The absorption band positions of all the compounds broadly lie between 280 and 336 nm and fluorescence band positions in the range between 300 and 370 nm, the near ultraviolet region.     

New monomers and polymers. V. Study of the spontaneous polymerization of 5-ethoxycarbonyl-3-formyl-2-pyrazoline

The 3-formyl-2-pyrazolines (pyrazoline-3-carboxaldehyde) obtained by 1–3 dipolar additions of diazoesters to acrolein are unstable and smoothly polymerize through the aldehyde group to a polyacetal polymer. On the basis of spectroscopic data, this paper describes the structure of the isolated polymers, along with their properties and a polymerization mechanism. It is proposed that a nucleophilic attack of an heterocyclic amino nitrogen on another monomer formyl group leads to an internal ion pair, and that this latter promotes a polycondensation of other aldehydic units according to an anionic type of propagation. The results are polyacetal polymers of low molecular weight with conservation of the heterocyclic framework. However, numerous side reactions are possible and account for the relatively low molecular weights observed.     

Versatility of the Biginelli reaction: Synthesis of new biphenyl dihydropyrimidin-2-thiones using different ketones as building blocks

A multi-component synthesis of biphenyl dihydropyrimidin-2-thiones from 1-phenylthiourea, aldehydes and ketones or di-ketones has been demonstrated. The reaction proceeded well for aldehydes with electron donor or acceptor substituents under mild conditions.     

Synthesis of 2,3-dihydro-1H-isoindole-1-thiones via the bromine–lithium exchange between 1-bromo-2-(1-isothiocyanatoalkyl)benzenes and butyllithium

The reaction of 1-bromo-2-(1-isothiocyanatoalkyl)benzenes, which are easily derived from 2-bromophenyl ketones or (2-bromophenyl)methanamine, with butyllithium generates 1-(1-isothiocyanatoalkyl)-2-lithiobenzenes, which immediately underwent intramolecular cyclization to give rise to the corresponding 3-substituted and 3,3-disubstituted 2,3-dihydro-1H-isoindole-1-thiones in good yields.     

Synthesis of 5-Formyl and 5-Acyl-1,2-dithiole-3-ones

The preparation of new 5-formyl-, 5-acetyl- and 5-propionyl-1,2-dithiole-3-ones by oxidation of the corresponding 1,2-dithiole-3-thiones with mercuric acetate is described.     

4-Functionally Substituted 3-Heterylpyrazoles: IV. 1-Phenyl-3-aryl(heteryl)-5-(4-pyrazolyl)-2-pyrazolines

3-Aryl(heteryl)-4-formylpyrazoles in condensation with methyl aryl(heteryl) ketones afforded 1-aryl(heteryl)-3-[3-aryl(heteryl)-4-pyrazolyl]propenones. The latter reacted with phenylhydrazine yielding 1-phenyl-3-aryl(heteryl)-5-(4-pyrazolyl)-2-pyrazolines.     

One-pot synthesis of diverse 4-di(tri)fluoromethyl-3-cyanopyridine-2(1H)-thiones and their utilities in the cascade synthesis of annulated heterocycles

Diverse substituted 4-di(tri)fluoromethyl-3-cyanopyridine-2(1H)-thiones were synthesized via the Claisen condensation of alpha-methyl(methylene)ketones with di(tri)fluoroacetate, followed by the immediate Thorpe-Guareschi reaction of the preformed di(tri)fluoromethyl-1,3-diketones with cyanothioacetamide. The procedure allows facile synthesis of the di(tri)flouromethylated pyridine-2(1H)-thiones in 50-95% yields, without the need for isolation and purification of intermediates. Resultant 4-di(tri)fluoromethyl-3-cyanopyridine-2(1 H)-thiones were subsequently utilized in domino reactions to produce first various substituted thieno[2,3-b]pyridines and, then, thienopyridines polyannulated with pyridine, pyrimidine, benzodiazocine, diazepine, and pyran rings.