Multicomponent one-pot synthesis of (dihydro-1H-benzo[d]imidazole) phosphonate

Abstract

We present a multicomponent reaction strategy to synthesize a (dihydro-1H-benzo[d]imidazole)phosphonate family of compounds, using benzimidazoles, diethyl chlorophosphate and aliphatic amines as starting reactants. Giving its simplicity, our procedure involves reaction times of only few hours and avoid the usage of any catalyst agent. All the newly synthesized compounds were characterized by Nuclear Magnetic Resonance spectroscopy (¹H, ¹³C and ³¹P) and mass spectrometry by the DART method.     

Heterocyclic Rearrangement of 4,5,6,7-Tetrahydro-6,6-dimethyl-benzo[c][1,2,5]oxadiazol-4-one (Z)-Arylhydrazones into Corresponding 2-Aryl-4,5,6,7-tetrahydro-2H-benzo[d][1,2,3]triazol-4-one Oximes

The thermal base-catalysed and photochemical transformation (Boulton-Katritzky rearrangement) of the title tetrahydrobenzo[c][1,2,5]oxadiazoles to tetrahydro-2H-benzo[d][1,2,3]triazoles is studied. Attempts to induce analogous rearrangement in tetrahydro-2H-benzo[d][1,2,3]triazol-4-one arylhydrazones or oximes failed. Some CNDO/2 calculation are also carried out.     

Chemical reactions of 4,5,6,7-tetrahydro-4,5,7-trimethylpyrrolo[3,2-c]pyridine and its 2-formyl derivative

N-Alkyl substituted tetrahydropyrrolo[3,2-c]pyridines have been obtained by alkylation of 4,5,6,7-tetrahydro-4,-5, 7-trimethylpyrrolo[3,2-c]pyridine and its 2-formyl derivative chloroalkyldimethylamines, acrylonitrile, methyl acetylenedicarboxylate and dichloroethane. 2-Formyl substituted tetrahydropyrrolo[3,2-c]pyridine has been reduced with sodium borohydride and condensed with monoethanolamine and hydroxylamine. The stereochemistry of the products has been studied by ¹H NMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 681–687, May, 1993.     

Electrophilic substitution reactions in 4H-benzo[d,e,f]carbazole

The behavior of 4H-benzo[d,e,f]earbazole and its N-aeetyl derivative in various electrophilic substitution reactions (e.g. nitration, nitrosation, bromination, Friedel-Crafts acylations) has been investigated, and a number of new derivatives of this heterocycle (some of which are to be tested as potential carcinogens and enzyme-inducers) have been synthesized.     

4,5,6,7-tetrahydro-5,7-dioxo-[1,2,4]triazolo-[1,5-a]pyrimidine: characterisation and theoretical study

4,5,6,7-tetrahydro-5,7-dioxo-[1,2,4]triazolo-[1,5-a]pyrimidine (H₂tpO₂) has been synthesized as well as its monosodic salt, the crystal structure of the latter having been determined by X-ray diffraction. H₂tpO₂ possesses a very acidic active methylene group, as indicated by its dissociation constant (pK_al = 2.9). One of the hydrogen atoms in this group could then migrate to a basic position of the molecule, generating a zwitterionic or enolic form, nevertheless molecular orbital calculations point to the tautomer that keeps the CH₂ group as the most stable one.The anionic form HtpO⁻₂ is generated by the elimination of one of the protons at C6 rather than that attached to N4, as indicated by NMR data and also by the X-ray diffraction data of Na(HtpO₂)·2H₂O, this being consistent with theoretical calculations. The role of the molecular orbitals of HtpO⁻₂ in possible coordination to metal ions is discussed.     

Synthesis and reactions of 1-benzylide neaminoimidazo[1,2-a]imidazoles

The method of synthesizing condensed imidazo-heterocyclic systems has been extended to the production of N-benzylideneaminoimidazo[1,2-a]imidazoles (VI, VII), the successive hydrolysis and treatment with nitrous acid of which has enabled N-substituted imidazo[1,2-a]imidazoles to be obtained. A by-product of the synthesis is 1,2-dibenzylideneamino-4-phenyl-5-n-propylimidazole (VIII), the condensation of the reduction product of which with isatin leads to a tetracyclic system.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1190–1193, September, 1973.     

Diastereoselective intermolecular Pauson-Khand reactions of chiral cyclopropenes

In this Letter, it is demonstrated that the unusual reactivity of cyclopropenes can increase the scope and utility of intermolecular Pauson-Khand reactions. The well-defined chiral environment of cyclopropenes has a powerful influence on the diastereoselectivity of the reactions and leads to the production of a single cyclopentenone in each of the described cases. The cyclopropane ring strongly influences the stereochemistry of reactions at the enone, and the three-membered ring can subsequently be cleaved under mild conditions. [reaction: see text]     

Transformations of 2-trifluoroacetyl-4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridines by the action of ethyl propynoate. A novel synthesis of 2-trifluoroacetyl-4,7,8,9-tetrahydro-1H-pyrrolo[2,3-d]azocines

2-Trifluoroacetyl-4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridines reacted with ethyl propynoate in acetonitrile and methanol to give ethyl 2-trifluoroaceyl-4,7,8,9-tetrahydro-1H-pyrrolo[2,3-d]azocine-5-carboxylates. The reactions of 2-trifluoroacetyl-1-vinyl-4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridines with ethyl propynoate in alcohols were accompanied by cleavage of the tetrahydropyridine fragment with formation of alkyl 3-{benzyl[2-(3-alkoxy-5-trifluoroacetyl-1-vinyl-1H-pyrrol-2-yl)ethyl]amino}acrylates.     

Synthesis and spectroscopic characterization of novel 2-amino-4,5,6,7-tetrahydro-3H-cyclopenta[d]pyrimidine and pyrimido[1,2-a]pyrimidine derivatives

2-Aminocyclopenta[d]pyrimidines 3a-c were achieved via a one-pot, three-component reactions of cyclopentanone 1, aromatic aldehyde and guanidine hydrochloride (1:2:1 molar ratio). Also, cyclization of 2,5-bis-(arylmethylidene)cyclopentanones 2 with guanidine hydrochloride (1:1 molar ratio) in methanol in the presence of sodiummethoxide afforded cyclopenta-[d]pyrimidines 3. Compound 3a has been shown to be a useful building block for the synthesis of some novel pyrimido[1,2-a]pyrimidines 5, 7 and 12. The structures of the newly synthesized compounds were confirmed on the basis of analytical and spectral data.     

Synthesis and structure of 4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]pyrimidines

Kharkov State University, 310077 Kharkov and Institute of Heteroorganic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 981–986, July, 1994.Original article submitted May 11, 1994.     

A facile route to 2,4-dihydro-1H-benzo[d][1,3]thiazines via silver-catalyzed tandem addition-cyclization reactions

Tandem addition-cyclization reactions of 2-alkynylbenzenamines with isothiocyanates catalyzed by silver triflate are described; they provide an efficient and practical route for the synthesis of 2,4-dihydro-1 H-benzo[ d][1,3]thiazines.     

1-Heptanesulfonic acid sodium salt： One pot efficient synthesis of 2-aryl- 1-arylmethyl- 1 H- 1,3-benzo[d]imidazoles

Synthesis of 2-aryl-1-arylmethyl-1H-1,3-benzo[d]imidazoles by the reaction of o-phenylenediamine with substituted aromatic aldehydes in the presence of l-heptanesulfonic acid sodium salt (10 mol%) at room temperature.The reactions were performed in acetonitrile:water (8:2).The method was proved to be eco-friendly,convenient and the products were isolated with good yields (82-90%).     

A convenient synthesis and structural analysis of novel 4,5,6,7-tetrahydro-1H-indazoles

A new series of t-4-aryl-3,c-6-dihydroxy-6-methyl-4,5,6,7-tetrahydro-1H-indazole-r-5-carboxylic acid isopropyl esters has been synthesized by adopting a conventional method from cyclic β-keto esters. ¹H, ¹³C NMR, and IR spectra for all the compounds were investigated. HMBC, HSQC, COSY, and NOESY spectra of the representative compounds were studied. The stereochemistry of a six-membered ring of the fused indazoles resembled that of keto esters. From the HMBC correlations the indazole structure was confirmed as 1H-indazole.     

Semmler-Wolff aromatization of 4-hydroxyimino-4,5,6,7-tetrahydro-[2,1,3]benzoxadiazole and 4-hydroxyimino-4,5,6,7-tetrahydro[2,1,3]benzoxadiazole 1-oxide and some properties of the obtained amines

The Semmler-Wolff aromatization of 4-hydroxyimino-4,5,6,7-tetrahydro[2,1,3]benzoxadiazole and its 1-oxide derivative in sulfuric acid and in acetic anhydride gave 4-amino[2,1,3]benzoxadiazole and 4-acetamido[2,1,3]benzoxadiazole 1-oxide. Some reactions of the resultant amines were studied.     

A chemoenzymatic synthesis of 3,4,5,6-tetrahydro-2H-benzo[b][1,4]-oxazocine-3,5-dione and its derivatives

Abstract  The enzymatic cyclization of phenoxyacetylcyanomethylenetriphenylphosphorane derivatives using pre-treated baker’s yeast cells, a rapid one-pot assembly of heteromacrocyclic compounds, is described. Graphical abstract        

Synthese von 3-Hydroxy-1-oxo-4-alkyl-1H-benzo[d]pyrido[2,1—b]thiazolen

Zusammenfassung -[Benzothiazolyl-(2)]-acetessigsäurealkylester können zu Benzopyridothiazolen cyclisiert werden. Bei Umsetzung solcher substituierter Acetessigester mit Alkylhalogeniden in Gegenwart von Basen erfolgt Cyclisierung zu Benzopyridothiazolen, die an C-4 alkylsubstituiert sind. IR- und¹H-NMR-Daten dieser Heterocyclen und einiger ihrer Derivate werden mitgeteilt.

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Synthesis of 3-hydroxy-1-oxo-4-alkyl-1H-benzo[d]pyrido-[2.1—b]thiazoles

Ring closure of -[benzothiazolyl-(2)]-acetoacetates affords benzopyridothiazoles. In the reaction of these substituted acetoacetic acid esters with alkyl halides in the presence of bases, the formation of benzopyridothiazoles is observed; these heterocyclic compounds are alkyl-substituted at C-4. IR- and¹H-NMR-spectral data of the benzopyridothiazoles and some of their derivatives are given.

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Aus der DissertationN. Hawlitzky, Freiburg im Breisgau, 1970.     

New synthesis of 3-amino-1H-benzo[f]chromene-2-carbonitriles

3-Amino-1H-benzo[f]chromene-2-carbonitriles were synthesized by non-catalytic reaction from Mannich bases of the naphthalene series and malononitrile. Reactive 1-benzylidene(or methylidene)naphthalen-2(1H)-ones were presumed as intermediate products.     

A photochemical synthesis of 11H-benzo[a]carbazole

11H-Benzo[a]carbazole was prepared from 5-acetamido-1,2,3,4-tetrahydronaphthalene in four steps. A Goldberg arylation followed by hydrolysis afforded N-phenyl-1,2,3,4-tetrahydro-5-naphthylarnine ( 3 ). Photolysis of 3 produced 1,2,3,4-tetrahydro-11H-benzo[a]carbazole ( 4 ) which was converted to 11H-benzo[a]-carbazole by dehydrogenation with chloranil.     

Diastereoselective synthesis of [1]rotaxanes via an active metal template strategy

Despite the impressive number of interlocked molecules described in the literature over the past 30 years, only a few stereoselective syntheses of mechanically chiral rotaxanes have been reported so far. In this study, we present the first diastereoselective synthesis of mechanically planar chiral [1]rotaxanes, that has been achieved using the active template Cu-mediated alkyne–azide cycloaddition reaction. This synthetic method has been applied to the preparation of a [1]rotaxane bearing a labile stopper that can then be substituted without disruption of the mechanical bond. This approach paves the way for the synthesis of a wide variety of mechanically planar chiral [1]rotaxanes, hence allowing the study of the properties and potential applications of this class of interlocked molecular architectures.

The first diastereoselective synthesis of mechanically planar chiral [1]rotaxanes has been achieved using the active template Cu-mediated alkyne–azide cycloaddition reaction.