Cyclodimerization of the Stevens Rearrangement Products from 4-Alkoxy-2-butynyl(alkoxycarbonylmethyl)dimethyl-ammonium Salts into Cyclohexene Derivatives

4-Alkoxy-2-butynyl(alkoxycarbonyl)dimethylammonium salts undergo 3,2-Stevens rearrangement by the action of the corresponding sodium alkoxides. Hydrolysis of the rearrangement products with dilute hydrochloric acid gives 3-alkoxy-2-oxo-3-pentenoic acid esters which are converted into 3-methylene-2-oxo-4-pentenoates via 1,4-elimination of alcohol. [2 + 4]-Cyclodimerization of 3-methylene-2-oxo-4-pentenoates leads to 1,4-bis(alkoxalyl)-4-vinylcyclohexenes.     

Stevens rearrangement of ammonium salts containing 2-propynyloxy or tert-butoxycarbonylmethyl groups

The Stevens rearrangement of ammonium salts containing 2-alkenyl, 2-alkynyl, or benzyl groups along with 2-propynyloxy or tert-butoxycarbonylmethyl was studied. Under the action of a suspension of sodium phenolate in benzene the salts containing a 2-propynyloxycarbonylmethyl group form 2-propynyl esters of 2-dialkylamino-4-pentenoic acids, whereas with sodium methylate as the basic reagent, rearrangement is preceded by an almost complete transesterification. The salts containing a tert-butoxycarbonylmethyl group undergo almost no transesterification under the action of sodium methylate. The tert-butyl fragment in the ester group of the salt with a benzyl group exerts a fairly strong effect on the regiochemistry of the rearrangement and on the prototropic isomerization of the 3,2-Stevens rearrangement of the salts with 2-butynyl or 3-phenyl-2-propynyl groups.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 8, 2004, pp. 1321–1326.Original Russian Text Copyright © 2004 by Babakhanyan, Ovakimyan, Grigoryan, Kocharyan.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis and thermal decomposition of haloalkoxy-sym-triazines. 7. Thermal decomposition of 2-dialkylamino-4-(2-chloroethoxy)-6-methoxyamino-sym-triazines

Two 2-dialkylamino-4-(2-chloroethoxy)-6-methoxyamino-sym-triazines were synthesized. It was established that when they are heated at 120° C, the 2-chloroethoxy group undergoes rearrangement with cyclization to give 2-dialkylamino-4-oxo-8-methoxy-6, 7-dihydroimidazo [1,2-a]-sym-triazines, the structure of which was confirmed by data from the IR, PMR, and mass spectra.See [6] for Communication 6.Translated from Khimiya Geterotsilicheskikh Soedinenii, No. 8, pp. 1122–1124, August, 1981.     

Photochemistry of 5,5-Dimethyl-2(5H)-thiophenone

On irradiation (λ > 305 nm) in alcohols, 5,5-dimethyl-2(5H)-thiophenone ( 1b ) is converted to (E)-4-mercapto-4-methyl-2-pentenoates 8 . These esters undergo a consecutive light-induced reaction affording thiolanes when irradiated in the presence of alkenes, and either 2,3-dihydrothiophenes or 3-thiabicyclo[3.1.0]hexanes with alkynes.     

Parallel solution-phase synthesis of 4-dialkylamino-2-methylsulfonyl-6-vinylpyrimidines

A simple and straightforward methodology for the parallel, solution-phase synthesis of novel 4-dialkylamino-2-methylsulfonyl-6-vinylpyrimidines 9a-j has been developed. Starting from 2-methylthio-6-[2-(p-toluensulfonyloxy)ethan-1-yl]-4(3H)-pyrimidinone (6), a three-step procedure (namely, tosylate substitution by amines, base-catalyzed rearrangement, and sulfide to sulfone oxidation) using a Buchi Sincore synthesizer gave the final products in high yield after simple ethyl acetate extraction and without further purification. Interestingly, when the final oxidation step was performed on 4-arylpiperazine derivatives 8g-j, the corresponding highly polar piperazine N-oxides 9g-j were obtained, which conversely needed chromatographic purification in order to give the pure products.     

Synthesis of 5-dialkylamino-1,2,3-triazoles and 2-amino-1-azirines from tertiary amides

The reaction of sodium azide with β-monosubstituted-α-chloroenamines (generated from tertiary amides) yields either 5-dialkylamino-1,2,3-triazoles or 2-amino-1-azirines according to the basicity of the amine substituent.     

Alkyl 3-amino-5-aryl-2-benzoyl-5-oxo-2-pentenoates as new chelating ligands and reagents of heterocyclic synthesis

A method for the synthesis of alkyl 3-amino-5-aryl-2-benzoyl-5-oxo-2-pentenoates from Ni chelates of alkyl benzoylacetates and aroylacetonitriles was proposed. The compounds obtained were used for preparation of ethyl 4-amino-6-aryl-2-phenylnicotinates and Ni and B chelates.     

Synthesis and thermal decomposition of halogenalkoxy(thio)-sym -triazines. 12. Synthesis and certain transformations of 2-dialkylamino-4-oxo-6-cyanodihydrothiazolo-sym-triazines

2-(2-Chloro-2-cyanoethylthio)-sym-triazines were synthesized by reacting mercapto-sym-triazines with 2,3-dichloropropionitrile in the presence of alkali and with 2-chloroacrylonitrile. Their rearrangement-cyclization leads to 2-dialkylamino-4-oxo-6-cyano-dihydrothiazolo-sym-triazones.For communication 11, see [7].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 978–980, July, 1987.     

A new efficient synthesis of substituted nazarov reagents. A wittig-horner-emmons approach

A highly stereoselective synthesis of terminally substituted ethyl 3-oxo-4-pentenoates $\text{3}$ from γ-phosphorylated ethyl acetoacetate $\text{2}$ and diverse carbonyl compounds was accomplished.     

Synthesis of furo[2,3-c]-2,7-naphthyridine derivatives via domino heterocyclization reaction

2-Amino-4-cyanomethyl-6-dialkylamino-3,5-pyridinedicarbonitriles were found to react with substituted oxiranes yielding 5,6-diamino-8-dialkylamino-1,2-dihydrofuro[2,3-c]-2,7-naphthyridine-9-carbonitriles. The oxirane ring was shown to be opened selectively from the unsubstituted side and further cyclization occurred with participation of 3-CN, but not 5-CN of the starting pyridines. The furonaphthyridines obtained were converted into 2-dialkylamino-5-methyl-9,10-dihydro-4H-furo[2,3-c]pyrimido[4,5,6-ij]-2,7-naphthyridine-1-carbonitriles and 2-dialkylamino-5,6,9,10-tetrahydro-4H-spiro{furo[2,3-c]pyrimido[4,5,6-ij]-2,7-naphthyridine-5,1′-cyclohexane}-1-carbonitriles by treatment with acetic anhydride and cyclohexanone, respectively. The structure of prepared compounds was confirmed unambiguously by X-ray crystallographic study.     

2,4-Diaminodihydropyridine

Aminolysis of 4-alkylamino- and 4-dialkylamino-2-methylthiodihydropyridines (· HI)1, 2 resp.. under various reaction-condition leads to assymmetrically or symmetrically substituted 2,4-bisalkylamino- or 2,4-bisdialkylamino-and 2-alkylamino-4-dialkylamino- or 2-dialkylamino-4-alkylaminodihydro-pyridines3, 4, 5, 6 resp. On treatment with alkali only the aminogroup in pos. 4 of the pyridines3, 4, 5, 6 is hydrolyzed and 4-hydroxy-2-aminopyridines9 are formed. Different substituted 2,4-diaminodihydropyridines3, 4, 5, 6 can also be synthesized by reaction of 4-hydroxy-2-aminopyridines (·HCl)9 with amines. Also the aminolysis of 4-alkylamino-annd 4-dialkylaminodihydropyridinthiones7, 8 resp. is described.

     

Synthesis of Triphenyltin 2-(1,2-Ethylenedithio) Methylene-3-Oxo-5-Aryl-4-Pentenoate

ac-oxo-ketenedithioacetalsandrelatedcompoundsareversatileSynhlonsinorghocsynthesis.'"Althoughtherehavebeennumerousreportsaboutmisfieldinrecentyears,l-6allofthestUdiescanberoughlydividedintotwoaspectsfoneistheapplicahonofac-oxo-ketenedithioacetalsinorganicsyntilesis,andtileoilleristilesindiesontilereachvityadjustCdbythedialkylthiogroupsinac-oxo-betenedi1illoacetals.WehavedevotCdoureffortstothelatter."82-(l,2-ethylenedithio)medlylene-3-oxo-5-aryl-4-pentenoacids3wereformedbycondonsahonofacylketC…     

The Carbon Zip Reaction: A Method for Expanding Carbocycles

A general method for enlargement of carbocyclic rings by the so called zip reaction is given. The Michael adducts of 2-nitrocycloalkanones with 3-oxo-4-pentenoates in the presence of tetrabutylammonium fluoride give in high yield compounds with the ring enlarged by four C-atoms. By this method 7-, 8-, and 12-membered cycloalkanones were converted respectively to 11-, 12-, and 16-membered functionalized carbocycles (see Scheme 2 and 3).     

Synthesis of amino derivatives of triazolopyrimidine

Heterocyclization of 1-(4,6-dimethylpyrimidin-2-yl)-4-R-thiosemicarbazides by the action of methyl iodide in ethanol in the presence of sodium acetate is accompanied by Dimroth rearrangement leading to the formation of 5,7-dimethyl-2-R-amino[1,2,4]triazolo[1,5-a]pyrimidines. Analogous heterocyclization of 4-aryl-1-(4-methyl-6-oxo-1,6-dihydropyrimidin-2-yl)thiosemicarbazides gives 3-arylamino-7-methyl-5-oxo-[1,2,4]triazolo[4,3-a]pyrimidines. The presence in the pyrimidine ring of a carbonyl group capable of forming hydrogen bond with protons of the amino group stabilizes the molecule, thus hampering the Dimroth rearrangement.     

A practical strategy for the synthesis of 2-dialkylamino-4-arylamino-6-aminopyrimidines

Starting from commercially available 4-amino-2,6-dichloropyrimidine, a practical four steps synthesis of 2-dialkylamino-4-arylamino-6-aminopyrimidines was developed. This strategy could introduce a diverse set of secondary amines and arylamines to displace the 2- and 4-chloro groups. The products of this route are otherwise difficult to access. In addition, 6-amino arylation was carried out to demonstrate the reactivity and utility of 2-dialkylamino-4-arylamino-6-aminopyrimidines as building blocks for assembling interesting aminopyrimidine molecules.     

Zur Chemie der 2,4-Diaminothiopyranyliumjodide Synthese von α,β,γ,δ-ungesättigten Thiocarbonsäureamiden

Aminolysis of 4-dialkylamino- and 4-alkylamino-2-methylthiothiopyranyliden iodides2 resp. under various reaction conditions leads to assymmetrically or symmetrically substituted 2,4-bisamino- or 2,4-bisdialkylamino- and 2-alkylamino-4-dialkylamino-or 2-dialkylamino-4-alkylamino- or 2-amino-4-dialkylaminodihydrothiopyranylium iodides3, 4, 5, 6 resp. On treatment with alkali 4-alkylamino- and 4-dialkylamino-2-alkylaminothiopyranylium iodides3,4 are hydrolysed to the 2-alkylimino-2H-thiopyranes7. 4-Alkylamino-2-dialkylaminothiopyranylium iodides5 react with alkali to give three products: the two stereoisomeres 2-dialkylamino-4-alkylimino-4H-thiopyranes9 A,B and theN,N-substituted α,β,γ,δ-unsaturated thiocarboxamide10. The hydrolysis of 2,4-bisdialkylaminothiopyranylium iodide6 a leads to the 2-dialkylamino-4H-thiopyran-4-one11 a, the 4-dialkylamino-2H-thiopyrane-2-one12 and theN,N-substituted unsaturated thiocarboxamide10 d. α,β,γ,δ-unsaturated thiocarboxamides10 a-c are formed by the reaction of 2-amino-4-dialkylaminothiopyranylium iodides3 a-c with diluted alkali. By heating with acids10 a-c are cyclisized to the 2-aminothiopyranylium derivates3.     

[2+4] Cycloaddition of tetracyanoethylene with dialkyl esters of 3-dialkylamino-1, 3-alkadiene-2-phosphonic acid

Dialkyl esters of 3-dialkylamino-1,3-alkadiene-2-phosphonic acid undergo [2 + 4] cycloaddition with tetracyanoethylene to give 1-(O,O-dialkylphosphono)-2-dialkylamino-3,3-dimethyl-4,4,5,5-tetracyano-2-cyclohexenes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2843–2845, December, 1989.     

Synthesis of 5,6-dihydro-4H-thiopyran-4-ones

The anions of 1,4-diaryl-3-buten-2-ones 1 reacts with arylisothiocyanates, yielding intermediates 4 which can ring close to 5,6-dihydro-4H-thiopyran-4-ones 5 . Under similar reaction conditions ethyl 3-oxo-4-pentenoates 7 gives the 6-spiropyrans 9 . Methylation of 3 gives the S-methylated open form 6 .     

Synthesis of 2-dialkylaminomethyltetrahydrofuran-3-ols

The reaction of esters of 4-R-3-methyl-2,3,4,5-diepoxyvaleric acids with secondary amines leads to the formation of esters of 4-R-5-dialkylamino-4-hydroxy-3-methyl-2,3-epoxyvaleric acids. The reduction of the latter with lithium tetrahydroaluminate and the cyclization of the reduction products in the presence of p-toluenesulfonic acid has given 2-dialkylaminoethyltetrahydrofuran-3-ols, the methiodides of which possess ganglion-blocking activity.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1443–1446, November, 1973.     

Reactions of thioquinanthrene with sodium alkanethiolates. The smiles rearrangement of diquinolinyl sulfides

Reactions of thioquinanthrene 1 with sodium alkanethiolates or S-alkylisothiouronium salts (in the presence of sodium hydroxide) at 70° in DMSO or DMF yielded 4,4′-dialkylthio-3,3′-diquinolinyl sulfides 3 , which were results of the S-S type of the Smiles rearrangement of primary reaction products - sodium 3-quinoline-thiolates 6. When the reactions were carried out at 20° the products were 3′,4-dialkylthio-3,4′-diquinolinyl sulfides 2.