Isolation of 1,2,3,4-tetrahydrobenzo[f]quinolin-2-ones on the reaction of 2-arylidenenaphthylamines with 4-hydroxycoumarin. IV

The reaction of 2-arylidenenaphtylamines with 4-hydroxycoumarin results in Hoffman-Martius type rearrangement yielding 2H-benzo[f][1]benzopyrano[4,3-b]quinolin-2-ones I and the compounds II. This work describes the structure elucidation of the compounds II. The structure was confirmed using ir, nmr and X-ray spectroscopy.     

Studies on the synthesis of heterocyclic compounds. III. Synthesis of 1,3,2-benzodioxa- and 1,3,2-benzoxathiarsole derivatives

The preparation and reaction of 1,3,2-benzodioxa- and 1,3,2-benzoxathiarsoles (IIa-b) are described. Spiran derivatives Va-c are obtained by treating IIa-b with Ia-b and triethylamine, while the reaction of IIa-b with sodium hydroxide, ethoxide and p-cresolate gives the compounds VIa-b, VIIa-b and VIIIa-b, that can evolve to Xa-b. Reaction of IIa-b with sodium p-toluenethio-late and n-butyllithium gave the compounds IXa-b and XIa-b respectively. The structure of the prepared compounds has been determined by elemental analysis and spectroscopic data.     

Synthesis of Pyrene‐based Planar Conjugated Polymers and the Regioisomers by Intramolecular Cyclization

Several planar conjugated polymers and model compounds containing pyrene units are synthesized. The precursor polymers and model compounds are obtained through the Pd(0)‐catalyzed Suzuki reaction, then the planar structure is formed through intramolecular cyclization in the presence of acid. We investigate the regioisomers in intramolecular cyclization reaction by using model compounds, suggesting that the syn‐ and anti‐structures are formed in ladder‐type polymer LP1 , and the syn‐structure is more easily formed in LP3 . The planar conjugated polymers and model compounds show untypical features of ladder‐type polymers, they display broad absorption and blue or blue‐green emission in solution, and interchain π‐π stacking in film still occurs. Moreover, the new polymers and model compounds are characterized by nuclear magnetic resonance (NMR) spectroscopy, gel‐permeation chromatography (GPC) and cyclic voltammetry (CV).     

Synthesis and biological activity of novel mitomycin C analogs derived from mitomycin A

A variety of mitomycin C analogs were synthesized from mitomycin A and their biological activities were studied. Mitomycin A ( 1 ) underwent nucleophilic displacement reactions involving intramolecular hydrogen migrations upon treatment with nitrogen nucleophiles bearing mobile hydrogens, but the mode of hydrogen migration depended on the nature of the nucleophiles. The reaction with alkoxyamines gave compounds 6 and 7 which have the 5H-6-alkoxyimino-4,7-dione structure in ring A of 1 . However, the reaction with hydroxylamine and benzoylhydrazine afforded compounds 11 and 13 which have the 4-hydroxy-6-hydroxyimino-7-one structure and the 4-hydroxy-6-hydrazono-7-one structure, respectively, in ring A of 1 . These products were converted into various types of mitomycin C derivatives by methylation with methyl iodide or dimethyl sulfate. The mechanistic features of these reactions are discussed. The in vitro and in vivo biological activities were tested by using P388 leukemia and Sarcoma 180 tumor cells. Several of the synthesized compounds exhibited better activity than that of mitomycin C.     

Synthesen und Kristallstrukturen von Dialkylgalliumhydriden — dimere versus trimere Formeleinheiten

Syntheses and Crystal Structures of Dialkylgallium Hydrides — Dimeric versus Trimeric Formula Units Dialkylgallium hydrides (R = Me, Et, iPr, iBu, neopentyl) were obtained on two different synthetic routes. The dimethyl and diethyl compounds were formed by the reaction of LiH with the corresponding dialkylgallium chlorides via lithium dialkyldihydridogallate intermediates, which so far have not been isolated in a pure form. On the second route, trialkylgallium compounds were treated with [GaH₃·NMe₂Et] to yield the dialkylgallium hydrides by a substituent exchange reaction. The dimethyl, diethyl and diisopropyl compounds are trimeric in solution. That trimeric structure was verified for the diisopropyl derivative by a crystal structure determination. Di(neopentyl)gallium hydride has a dimeric structure in solution and in the solid state.     

Synthesis of heterocyclic analogs of isoflavone and homoisoflavone based on 3-formylchromone

The review is focused on recent developments of chemistry of synthetic analogs of natural compounds, isoflavone and homoisoflavone. The possible synthetic strategies to access heterocyclic analogs of these compounds starting from readily available 3-formylchromone and its derivatives (3-cyanochromone, 2-amino-3-formylchromone) and products of its condensation with simplest C- and N-nucleophiles are discussed. The structural features of the reaction products that depend on the nature of the reaction medium, structure of the starting compounds, and reagent ratio are considered. Particular attention is given to the application of the modern strategies of organic synthesis, namely green chemistry approaches, click reactions, domino reactions, etc. Examples of compounds of this group most promising for clinical application due to wide and pronounced pharmacological effects are given.

     

Tandem heterocyclization of 2-(azolyl-(azinyl-))anilines as an efficient method for preparation of substituted pyrrolo[1,2-a]azolo-(azino-)[c]quinazolines

The synthesis of novel pyrrolo[1,2-a]azolo-(azino-)[c]quinazolines by tandem reaction of 2-(azolyl-(azinyl-))anilines with oxocarboxylic acids was described in this article. The mechanism of obtained compounds formation was proposed, and the intermediate of the heterocyclization has been isolated and characterized. The IR-, ¹H and ¹³C NMR-, chromato-mass spectra of synthesized compounds were studied for estimation of their structure and spectral patterns features. The molecular structure of the obtained compounds was additionally proved by X-ray diffraction method.     

Kinetics of gas-liquid ozonization of veratrole and its derivatives

The kinetics was studied for the reactions of ozone with model lignin compounds, viz., phenol, veratrole, veratric aldehyde, and veratric alcohol. Using the mass transfer model for a chemical reaction based on the film theory, the reaction rate constants were calculated. The reaction rate constants determined by both the ozone absorption rate and changes in the substrate concentration coincide satisfactorily, indicating adequacy of the kinetic model chosen. A relationship between the structure of the compounds under study and their reactivity was found. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1941–1946, October, 2007.     

Catalytic olefination of carbonyl compounds. A new versatile method for the synthesis of alkenes

The review is devoted to a new catalytic olefination reaction (COR) discovered by the authors. This is the reaction between N-unsubstituted hydrazones of carbonyl compounds with dihalides CHal₂XY in the presence of copper(i) chloride to give substituted alkenes. Catalytic olefination is versatile. Variation of the carbonyl and olefinating components opens up the way for the synthesis of various classes of unsaturated compounds including those containing functional groups. The reaction mechanism is discussed and a catalytic cycle describing the process is proposed. A model for estimating and predicting the reactivity of halogen-containing compounds in the COR is developed. The relationship between the structure of the carbonyl substrates and their behavior in the title reaction is elucidated.     

Amination of Malononitrile Dimer to Amidines: Synthesis of 6‐aminopyrimidines

Reactions of amidines with malononitrile dimer in DMF and catalyzed with piperidine are reported. The reaction occurred via amination process followed by cyclization to give racemic 6‐aminopyrimidine compounds. The reaction mechanism was discussed. The structure of products was elucidated by mass spectrometry, IR and NMR spectra together with elemental analyses.     

Chemistry of novolac resins. X. Polymerization studies of HMTA and strategically synthesized model compounds

The reactions between hexamethylenetetramine (HMTA) and compounds which model novolac resins have been studied by ¹³C‐ and ¹⁵N‐NMR techniques. The dimer and tetramer compounds vary in molecular size and structure and react with HMTA to yield benzylamines and benzoxazine as the major initial‐formed intermediates and convert to methylene linked compounds at increased temperatures. The reaction of the compounds with only ortho reactive sites paralleled the 2,4‐xylenol–HMTA case reported by us previously; however, increasing molecular weight favored the formation of benzylamines and not benzoxazines. Those compounds with only para reactive sites paralleled the 2,6‐xylenol–HMTA case. The reactivity of the systems containing both ortho and para reactive sites depends on the ratio of ortho/para sites and various aspects such as the chemical structure and molecular weight of the compound, the HMTA level, and the melting point and pH of the system. These results parallel those obtained from novolac/HMTA systems. The xylenol/HMTA reactions formed similar products but showed quite different relative reaction rates by varying the HMTA ratio and structures of the materials. The importance of careful selection of model systems is also discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1347–1355, 1999     

Reactions of N- and C-Alkenylanilines: IV. Synthesis of Heterocycles by Oxidation of N-Acyl-o-(1-alkenyl)anilines with Hydrogen Peroxide

Heterocyclic compounds of the 4H-3,1-benzoxazine and cyclopenta[b]indole series were syn- thesized by oxydation of N-acyl derivatives of 2-(1-alkenyl)anilines with hydrogen peroxide. The structure of the oxidation products is determined by the reaction conditions, substituent in the ortho-position of the aromatic ring, protecting group, and alkenyl radical structure.     

Réactions de Transposition Ionique et de Rétrocycloaddition de Dihydro-3a, 8a Pyrazolo (3,4-b) Indoles Sous l'Impact Electronique

Three isomeric compounds, one having a 3a,8a-dihydropyrazolo (3,4-b) indole, the second an aryl-indolyl-ketone-hydrazone and the third a 1,3,4-triarylpyrazole structure give the same mass spectrum, which results from the superposition of the corresponding spectra of the first two compounds, which equilibrate after ionization. The 3a,8a-dihydropyrazolo (4,3-b)indoles proceeding from the second method of cycloaddition, also have the same fragmentation pathway. This makes a determination of the structure of the compounds formed by the cycloaddition reaction impossible by mass spectrometry.     

Amidoalkylation of hydrophosphoryl compounds

A new mild procedure of the amidoalkylation of hydrophosphoryl compounds in a mixture of acetic anhydride and acetyl chloride was developed as a convenient method of constructing the α-aminophosphoryl fragment of the pseudo-α,α′-dipeptide molecule. The reaction intermediates N,N′-benzylidene- and N,N′-alkylidenebiscarbamates were detected, isolated, and identified. The report presents the results of studying the direct interaction of hydrophosphoryl compounds previously synthesized with biscarbamates in acetic anhydride and other solvents, the influence of the structure of phosphorus component and biscarbamate, and the effect of acid catalysis on the course of this two-component reaction. A new version of the mechanism of the three-component reaction of amidoalkylation of hydrophosphoryl compounds is suggested: it is regarded as a multistage process involving the stage of biscarbamate formation followed by the stage of Arbuzov-type reaction with the intermediate formation of acyliminium cation and P-OAc derivative with trivalent phosphorus.     

Synthesis ofo-thiatelluraphenylenezirconocenes. X-ray crystal structure of

o-Thiatelluraphenylenezirconocene complexes were obtained in good yield by reaction of dilithiumo-benzenthiatelluride with zirconocene dichlorides. These compounds represent the first examples of heterodichalcogenaphenylene bent metallocences. They were characterized by spectroscopic methods and the effect on the n.m.r. results of stepwise substitution of one and two Te atoms for S is discussed. X-ray crystal structure analysis was performed for one representative complex. The structure is very similar to that previously reported for a diselenaphenylene complex, but the disorder observed for chalcogen atoms prevents an accurate comparison of the geometrical parameters with other related compounds.     

Synthesis of alkaloid-like compounds via the bridging Ritter reaction

Abstract  

Alkaloid-like compounds containing a benzo[c]azepine core structure were successfully prepared in three steps from 5H-dibenzo[a,d]cyclohepten-5-ol via the bridging Ritter reaction. Biological studies of these compounds revealed that some of them are AChE inhibitors and antimalarial agents.     

Rearrangements of the aminoalkylation products of tetrahydro-2H-1,3-oxazine-2-thione

The nature of the compounds afforded by the rearrangement of the aminopropylation and aminoethylation products of tetrahydro-2H-1,3-oxazine-2-thione (I) has been investigated. In both instances compounds that can be considered to result from ring opening at either the C-O or C-S bond of a hypothetical bicyclic intermediate of structure IV were obtained. The compounds required for identification of the rearrangement products have been prepared by the reaction of the 2-methylthio derivatives of 2-thiazoline, 5,6-dihydro-4H-1,3-thiazine, and 5,6-dihydro-4H-1,3-oxazine with the appropriate hydroxyalkylamine or mercaptoalkylamine.     

An Eco‐friendly Synthesis and Biological Screening of Fused Heterocyclic Compounds Containing a Thiophene Moiety via Gewald Reaction

5‐Amino‐3‐phenyl‐1‐(2,4,6‐trichlorophenyl)‐1H‐thieno[3,2‐c]pyrazole‐6‐carbonitrile ( 2 ) was designed and synthesized by one‐pot multicomponent reaction. Compound 2 was reacted with different reagents to obtain new condensed moieties with our thienopyrazole skeleton. The compounds were prepared by using environmentally benign techniques as microwave irradiation, ultrasonic irradiation, and ball‐milling. The structure of the prepared compounds was elucidated through spectroscopic methods. The new compounds were evaluated for their in vitro antibacterial and antifungal potentialities.     

A Facile Three‐Component One‐Pot Synthesis of Some Novel Tricyclic Hetero‐Ring Systems

A novel, facile, one‐pot, multicomponent reaction for the synthesis of a series of pyrano[2,3‐d][1,2,4]triazolo[4,3‐a]pyrimidine and pyrano[2′,3′:4,5]pyrimido[2,1‐b][1,3,5]thiadiazine derivatives has been developed from reaction of 2,4‐dichlorobezaldehyde, malononitrile, and the appropriate active methylene compounds in refluxing dioxane in the presence of chitosan. A plausible mechanism has been proposed for this reaction, and the structure of the newly synthesized compounds was all established on the basis of spectral data (mass, IR, and ¹H‐NMR) and elemental analyses.     

Regularities and Features of the Reaction of 2-Amino-6-nitro- and 2,6-Diaminobenzothiazoles with Ethylene Chlorohydrin

The alkylation of 2-amino-6-nitro- and 2,6-diaminobenzothiazoles by ethylene chlorohydrin has been studied. A comparative analysis has been made of the composition of these reaction mixtures and of those obtained from other 2-aminobenzothiazoles using this reaction. The structure of the synthesized compounds was confirmed using IR and ¹H NMR spectroscopy, mass spectrometry, and X-ray diffraction and via alternative syntheses.