Nucleophilic reactions of l-methyl-2-methoxy-2-phenyl-3-oxo-2,3-dihydroindole

The title compound (1) was prepared via methylene blue (MB)-sensitized photooxy-genation of l-methyl-2-phenylindole (2d) in methanol. Acid-catalyzed nucleophilic substitution of 1 with nucleophiles gave 1,2,2-trisubstituted 3-oxo-2,3-dihydroindoles (3–6). Reduction of 1 with lithium aluminum hydride, followed by acidic workup yielded 4d and 2d, whereas the same reduction reaction of 1, followed by neutral workup gave l-methyl-2-phenyl-3-hydroxy-2,3-dihydroindole (15), together with 3. The reaction pathways of nucleophilic substitution and reduction of 1 were discussed.     

Reaction of α,α-, α,α′-dihalothiones with 8-mercaptoquinolinium halides as a route to tetrahydro-1,4-thiazinoquinolinium halides

The reaction of 8-mercaptoquinolinium bromide with 1,3-dibromopropane-2-thione or 3,3-dibromobutane-2-thione in methanol gave the 2-bromomethyl-2-mercaptotetrahydro-1,4-thiazino[2,3,3,4-i,j]quinolinium and 3-bromo-2-mercapto-2,3-dimethyltetrahydro-1,4-thiazino[2,3,3,4-i,j]quinolinium bromides which readily exchanged the Br⁻ anion for ClO ₄ ⁻ upon treatment with sodium perchlorate in methanol. Oxidation of the 3-bromo-2-mercapto-2,3-dimethyltetrahydro-1,4-thiazino[2,3,3,4-i,j]-quinolinium bromide by selenium dioxide gave 2,2-dithiobis(3-bromo-2,3-dimethyltetrahydro-1,4-thiazino[2,3,3,4-i,j]quinolinium) bromide. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1720–1723, November, 2006.     

Site-selective Suzuki-Miyaura reactions of 2,3-dibromo-1H-inden-1-one

The first transition metal-catalyzed cross-coupling reactions of 2,3-dibromo-1H-inden-1-one are reported. The Suzuki-Miyaura reaction of 2,3-dibromo-1H-inden-1-one with 2 equiv of arylboronic acid gave 2,3-diaryl-1H-inden-1-ones. The reaction with 1 equiv of arylboronic acid gave 2-bromo-3-aryl-1H-inden-1-ones with very good site-selectivity. The one-pot reaction of 2,3-dibromo-1H-inden-1-one with two different arylboronic acids afforded 2,3-diaryl-1H-inden-1-ones containing two different terminal aryl groups.     

Reaction of 5-phenyl-2,3-dihydrofuran-2,3-dione with 6,7-dimethoxy-3,4-dihydroisoquinoline. Crystal structure of 1-benzoyl-8,9-dimethoxy-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-dione

The reaction of 5-phenyl-2,3-dihydrofuran-2,3-dione with 6,7-dimethoxy-3,4-dihydroisoquinoline gave 1-benzoyl-2-hydroxy-8,9-dimethoxy-3,5,6,10b-tetrahydropyrrolo[2,1-a]isoquinolin-3-one and its oxidation product,viz., 1-benzoyl-8,9-dimethoxy-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-dione. The last-mentioned compound was studied by X-ray structural analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1845–1848, October, 1997.     

Investigations in the Field of 2,3'-Biquinolyl. 14. Reaction of Dihydro Derivatives of 2,3'-Biquinolyl with Bromine and Iodine

Methods were developed for the synthesis of 6'-bromo- and 6',8'-dibromo-2,3'-biquinolyls and 3',4'-dibromo- and 3',4',6'-tribromo-1'-ethoxycarbonyl-1',2',3',4'-tetrahydro-2,3'-biquinolyls on the basis of the bromination of the dihydro derivatives of 2,3'-biquinolyl. It was shown that the reaction of 1'-alkyl-1',4'-dihydro-2,3'-biquinolyls with bromine and iodine leads to 1'-alkyl-1',2'-dihydro-2,3'-biquinolyl-2'-ones.     

Cyanoacetylene and Its Derivatives. 30. Reactions of 2,3-Dimercaptoquinoxaline with 3-Phenyl-2-propynonitrile and 4-Alkyl-4-hydroxy-2-alkynonitriles

The reaction of 2,3-dimercaptoquinoxaline with 3-phenyl-2-propynonitrile (~10 mass % KOH, 20-25°C, 5 h, dioxane) gave the S,S-diadduct (as with unsubstituted acetylene). 2,3-Dimercaptoquinoxaline reacted with 4-alkyl-4-hydroxy-2-alkynonitriles to give 2-cyanomethyl-2-(1-hydroxy-1-alkyl)-1,3-dioxolano[4,5-b]quinoxalines or 3-cyanomethylene-8-imino-2,2,6,6-tetramethyl-1,7-dioxa-4-thiaspiro[4.4]nonane.     

Acetylenchemie, 33. Mitt.: Synthese von 2-substituierten Dihydrofuro[2,3-b]chinolinen

Summary The reaction of 3-iodo-4-methoxy-2(1H)-quinolinone (1) and 3-iodo-4,6,8-trimethoxy-2(1H)-quinolinone (2) with 2-methyl-3-butyn-2-ol under modified Heck-conditions gave the 2-substituted derivatives 2-(1-hydroxy-1-methylethyl)-4-methoxyfuro[2,3-b]-quinoline (3) and 2-(1-hydroxy-1-methylethyl-4,6,8-trimethoxyfuro[2,3-b]-quinoline (4). By a subsequent hydrogenation-reaction with a homogeneous catalyst (PtO₂/Rh₂O₃), the furoquinoline-derivatives yielded the dihydrofuro-[2,3-b]quinolines, identified as 2-(1-hydroxy-1-methylethyl-4-methoxy-2,3-dihydrofuro[2,3-b]quinoline (5) (racemic platydesmine) and 2-(1-hydroxy-1-methylethyl)-4,6,8-trimethoxy-2,3-dihydrofuro-[2,3-b]quinoline (6) (racemic precursor of O⁴-methylptelefolonium salt).

     

Synthesis and crystal structure of ethyl 1-benzyl-2-hydroxy-5-methyl-3-oxo-2-phenacyl-2,3-dihydropyrrole-4-carboxylate

Reaction of 5-phenyl-2,3-dihydro-2,3-furandione with ethyl 3-benzylamino-2-butenoate, resulting in ethyl 1-benzyl-2-hydroxy-5-methyl-3-oxo-2-phenacyl-2,3-dihydropyrrole-4-carboxylate and benzylamide ofN-benzoylpyruvic acid, was studied. The structure of the pyrrole derivative was confirmed by X-ray analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1552–1555, August, 1995.     

Transformations of anilides of 3-aryl-2,3-epoxypropionic acids when exposed to acidic agents

Anilides of 3-aryl-2,3-epoxypropionic acids on treatment with aqueous HBr gave 3-aryl-3-bromo-2-hydroxypropionic acid anilides and (in some cases) 2-bromo-3-hydroxy regioisomers. Cyclization of these products into 3-arylquinolin-2(1H)-ones was studied.     

The chemical behavior of 2-methylene-2,3-dihydro-3-furanones

Diphenylketene undergoes regioselective thermal [2+2]-cycloaddition to the heterocyclic C(3)=O carbonyl group of 5-aryl-2-methoxycarbonylmethylene-2,3-dihydrofuran-3-ones and 5-phenyl-2,3-dihydrofuran-2,3-dione to give the corresponding 3-diphenylmethylene derivatives of 2,3-dihydrofuran.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 331–334, February, 1995.     

Structural Determination of the [4+2] Dimer of 2,3-Dimethylene-2,3-Dihydrothiophene from Deuterium Labeling Study

2,3-Dimethylene-2,3-dihydrothiophene (1a), prepared by the flash vacuum pyrolysis of 3-methyl-2-thienylmethyl benzoate (7a), rapidly dimerizes to form a [4 + 2] dimer 6. The structure of the [4+2] dimer 6 was confirmed by comparing its NMR spectrum with that of the [4 + 2] dimers from 2-dideuteriomethylene-3-methylene-2,3-dihydrothiophene (1b) and 2-methylene-3-dideuteriomethylene-2,3-dihydrothiophene (1c).     

Nucleophilic reactions of 1-methyl-2-methoxy-2-phenyl-3-oxo-2,3-dihydroindole

The title compound (1) was prepared via methylene blue (MB)-sensitized photooxy-genation of l-methyl-2-phenylindole (2d) in methanol. Acid-catalyzed nucleophilic substitution of 1 with nucleophiles gave 1,2,2-trisubstituted 3-oxo-2,3-dihydroindoles (3-6). Reduction of 1 with lithium aluminum hydride, followed by acidic workup yielded 4d and 2d, whereas the same reduction reaction of 1, followed by neutral workup gave l-methyl-2-phenyl-3-hydroxy-2,3-dihydroindole (15), together with 3. The reaction pathways of nucleophilic substitution and reduction of 1 were discussed.     

Studies on the Synthesis of New 3-(3,5-Diamino-1-substituted-pyrazol-4-yl)azo-thieno[2,3-b]pyridines and 3-(2-Amino-5,7-disubstituted-pyrazolo[1,5-a]pyrimidine-3-yl)azothieno[2,3-b]pyridines

Coupling the diazonium salt of 3-amino-2-cyano-4,6-dimethylthieno[2,3-b]pyridine 1 with malononitrile 2 gave 2-cyano-3-(hydrazonomalononitrile)-4,6-dimethylthieno[2,3-b]pyridine 3 which then reacted with hydrazine compounds 4a-4h to yield corresponding 2-cyano-3-(3,5-diamino-1-substituted-pyrazol-4-yl)azo-4,6-dimethylthieno[2,3-b]pyridines 5a-5h. The 2-cyano-3-(2-amino-5,7-disubstituted-pyrazolo-[1,5-a]pyrimidine-3-yl)azo-4,6-dimethylthieno[2,3-b]pyridines 7a-7f were obtained in good yield by the cyclocondensation reaction of 2-cyano-3-(3,5-diamino-pyrazol-4-yl)azo-4,6-dimethylthieno[2,3-b]pyridine 5a with the appropriate 1,3-diketones 6a-6f under acidic condition.     

A route to fluorocontaining N,S-heterocycles via octafluoro-2,3-epoxybutane

The reaction of octafluoro-2,3-epoxybutane 1 with 2-aminothiophenol gave three kinds of novel fluorocontaining N,S-heterocyclic compounds depending on the solvent nature: 2,3-bis(trifluoromethyl)-3,4-dihydro-2H-1,4-benzothiazin-2-ol 2, 2-trifluoromethyl-2-[1-(2-aminophenylthio)-2,2,2-trifluoroethyl]-1,3-benzothiazolidine 6 and 5a,11a-bis(trifluoromethyl)-5a,6,11a,12-tetrahydro-5,11-dithia-6,12-diazanaphthacene 5. Use of the toluene, dioxane, tetrahydrofuran, acetonitrile and dimethoxyethane gave the unexpected dihydrobenzothiazine 2 (RS,SR > RR,SS) in good to moderate yields. In dimethylsulfoxide and N,N-dimethylacetamide, unusual cyclization occurred resulting in benzothiazolidine 6 (RS,SR/RR,SS ∼ 1:1) in moderate yields. Formation of minor 1,1,1,3,4,4,4-heptafluoro-3-(2-aminophenylthio)-2,2-dihydroxybutane 4 which was converted into bis(benzothiazine) 5 was observed in all solvents tested with the exception of toluene and dioxane. The molecular structure of the RS,SR-diastereomer of dihydrobenzothiazine 2, bis(benzothiazine) 5 and the RS,SR-diastereomer of benzothiazolidine 6 has been established by X-ray crystallography.     

The investigation in 2,3'-biquinoline series 26.* Regioselective nitration of 1'-alkyl-1',4'-dihydro-2,3'-biquinolin-4'-ones and 1'-alkyl-1',2'-dihydro-2,3'-biquinolin-2'-ones

The nitration of 1'-alkyl-1',4'-dihydro-2,3'-biquinolin-4'-ones and 1'-alkyl-1',2'-dihydro-2,3'-biquinolin-2'-ones has been investigated. It was shown that the regioselectivity of nitration of the first depends on the acidity of the medium and the order of adding reactants. In strongly acidic medium 1'-alkyl-5,6'-dinitro-1',4'-dihydro-2,3'-biquinolin-4'-ones or mixtures of them with 1'-alkyl-5-nitro-1',4'-dihydro-2,3'-biquinolin-4'-ones are formed. In less acidic media 1'-alkyl-6'-nitro-1',4'-dihydro-2,3'-biquinolin-4'-ones and then 1'-alkyl-6,6'-dinitro-1',4'-dihydro-2,3'-biquinolin-4'-ones are formed. Nitration of 1'-alkyl-1',2'-dihydro-2,3'-biquinolin-2'-ones leads to 1'-alkyl-6'-nitro-1',2'-dihydro-2,3'-biquinolin-2'-one and then 1'-alkyl-6,6',8'-trinitro-1',2'-dihydro-2,3'-biquinolin-2'-one. *For Communication 25 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 578-585, April, 2009.     

Investigation of 2,3'-Biquinolyl. 10. The Regioselectivity of the Reaction of 2,3'-Biquinolyl and 1'-Alkyl-3-(2-quinolyl)quinolinium Halides with Halo Derivatives in the Presence of Metallic Lithium and Magnesium

2,3'-Biquinolyl reacts with halo derivatives in the presence of metallic lithium to give addition products at position 4', treatment of which with water gives 4'-R-1',4'-dihydro-2,3'-biquinolyls and with halo derivatives gives 1'-alkyl-4'-R-1',4'-dihydro-2,3'-biquinolyls. The reaction of 2,3'-biquinolyl with halo derivatives in the presence of metallic magnesium gives a mixture of products of addition at positions 2' and 4'. 1-Alkyl-3-(2-quinolyl)quinolinium halides and halo derivatives with metallic magnesium give 1'-alkyl-2'-R-1',2'-dihydro-2,3'-biquinolyls but form a complex mixture of substances when metallic lithium is used.     

Reduction of indolo[2,3-b]quinoxalines

Reduction of indolo[2,3-b]quinoxalines with zinc in the presence of an anhydride gave N,N-diacyl trapped 6,11-dihydroindolo[2,3-b]quinoxalines in 43-92% yields. When the reduction with zinc was performed in TFA/TFAA, an unexpected ring opened product was isolated in 49% yield. The structure of this product could be identified as 1,2-dihydro-1-trifluoroacetyl-3-[(2-trifluoroacetylamino)phenyl]quinoxaline.     

2-[2-(2,3-Dihydrobenzimidazolylidene)]- and 2-[2-(2,3-Dihydropyrido[2,3-d]imidazolylidene)]-5,5-dimethyl-1,3-cyclohexanediones

The reaction of 2-aminocarbonyl-5,5-dimethyl-1,3-cyclohexanedione with 2,3-diaminopyridine, 1,2-phenylenediamine (and its 4-methyl, 4-nitro, 4-carboxy, and 4-benzoyl derivatives), and 3,3-diaminobenzidine gave the corresponding 2-[2-(2,3-dihydrobenzimidazolylidene)]- and 2-[2-(2,3-dihydropyrido[2,3-d]imidazolylidene)]-5,5-dimethyl-1,3-cyclohexanediones. Their structure was confirmed by ¹H NMR spectroscopic data and X-ray analysis.     

Oxidative cyclization of 3-oxopropanenitriles with α,β-unsaturated amides by manganese(III) acetate. Regio- and stereoselective synthesis of 4-cyano-2,3-dihydrofuran-3-carboxamides

4-Cyano-2,3-dihydrofuran-3-carboxamides were obtained from the oxidative cyclization of 3-oxopropanenitriles with unsaturated amides using manganese(III) acetate. Treatment of 3-oxopropanenitriles with (2E)-3-(5-methyl-2-furyl)acrylamide and (2E)-3-(2-thienyl)acrylamide gave 2-(5-methyl-2-furyl) and 2-(2-thienyl) substituted 4-cyano-2,3-dihydrofuran-3-carboxamides in moderate yields, respectively. However, (2E)-3-(2-furyl)acrylamide and (2E)-3-phenylacrylamide did not produce any product under the same conditions. On the other hand, reaction of a dienamide such as (2E,4E)-5-phenylpenta-2,4-dienamide with 3-oxopropanenitriles gave diastereomeric mixtures of 2-(2-vinylphenyl)-4-cyano-2,3-dihydrofuran-3-carboxamides. Mechanisms are proposed for the formation of all of these compounds.     

Substituted chromones in [3+2] cycloadditions with nonstabilized azomethine ylides: synthesis of 1-benzopyrano[2,3-c]pyrrolidines and 1-benzopyrano[2,3-c:3,4-c′]dipyrrolidines

Chromones bearing electron-withdrawing substituents at the 2- or 3-position react with nonstabilized azomethine ylides to produce 1-benzopyrano[2,3-c]pyrrolidines in good yields. Reactions of 3-cyanochromones proceed diastereoselectively to give 1-benzopyrano[2,3-c]pyrrolidines and tetrahydro-1H-spiro[chromeno[2,3-c]pyrrol-9,5′-oxazolidine]-9a-carbonitriles, depending on the reactant ratio, as a result of a 1,3-dipolar cycloaddition of the azomethine ylide at the double bond and carbonyl group of the chromone system. The latter undergoes demethylenation and recyclization into a novel hexahydrochromeno[2,3-c:3,4-c′]dipyrrole tetracyclic system on heating with hydrochloric acid.