Synthesis and cycloaddition reactions of ethyl glyoxylate imines. Synthesis of substituted furo-[3,2-c]quinolines and 7H-indeno[2,1-c]quinolines

Lewis acid catalyzed cycloaddition reactions of ethyl glyoxylate imines to dihydrofuran and indene yield substituted hexahydrofuro[3,2-c]- and tetrahydro-7H-indeno[2,1-c]quinolines respectively. Oxidation of the adducts with 2,3-dichloro-5,6-dicyanobenzoquinone affords the corresponding aromatic compounds.     

Synthesis of substituted pyrrolo[3,2-f]quinolines

Reactions of 2,3,6-trimethyl- and 2,6-dimethyl-6-methoxy-5-aminoindoles with 1,3-dicarbonyl compounds represent a convenient route for obtaining substituted pyrrolo[3,2-f]quinolines, even though the presence of a methoxy group on the benzene ring sometimes lowers the reactivity of the amine, thus increasing the required reaction time and reducing the yield.M. E. Evsev'ev Mordovian State Pedagogical Institute, Saransk 430007. M. V. Lomonosov Moscow State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1080–1087, August, 1997.     

Synthesis of 6-fluoroalkylbenzo[h]cyclopenta[c]quinoline and -benzo[c]phenanthridine derivatives

Russian Chemical Bulletin -     

Synthesis of substituted 1H-pyrrolo[3,2-c]quinolines

1H-2-Phenylpyrrolo[3,2-c]quinoline (1a) is made by thermal cyclization of quinol-4-yl hydrazone. Subsequent substitution of the C-3 hydrogen atom of the pyrrole ring of 1a with chlorine and a formyl group is easily achieved by reacting 1a with trichloroacetyl chloride and phosphorus oxychloride in DMF, respectively.     

[2 + 2] Cycloaddition reactions of unsymmetrically substituted carbodiimides

N-Alkyl-N′-arylcarbodiimides add alkyl and aryl isocyanates to the N-alkyl substituted CN double bond to yield 4-arylimino-1,3-diazetidine-2-ones 3. In the case of bulky alkyl substituents the reaction still proceeds across the sterically hindered CN double bond. N-Aryl-N′-[(4-dimethylamino)phenyl]carbodiimides form [2 + 2] cycloadducts with aryl isocyanates preferentially across the CN double bond not attached to the electron-rich aryl groups. However, steric crowding on this CN double bond directs the reaction to the adjacent double bond of the heterocumulative system. The rate of the [2 + 2] cycloaddition reaction of N'-methyl-N′-phenylcarbodiimide with 4-nitrophenylisocyanate is about 2.5 times faster in acetonitrile than in benzene.     

Synthesis of 2H-pyrano[2,3-b]quinolines. Part I

3,4-Dihydro-2H-pyrano[2,3-b]quinolines 5a-e and 2H-pyrano[2,3- b ]quinolines 10a-c were synthesised starting from the appropriate ω-chloro-n-valeroylanilides 2a-e . Compounds 10a-c were transformed to analogs of the novel antihypertensive agent Cromakalim ( 1 ).     

Synthesis of indolo[1,2-f]phenanthridines from palladium-catalyzed reactions of arynes

A novel convenient approach for the construction of indolo[1,2-f]phenanthridine was developed from the reaction of arynes with 1-(2-bromophenyl)-1H-indole in the presence of palladium catalyst.     

Synthesis and spectral-luminescence properties of some substituted 1,3-diarylbenzo[f]quinolines

Amino derivatives of 1,3-diarylbenzo[f]quinoline were synthesized and subjected to reaction with methyl vinyl ketone in the presence of catalytic amounts of concentrated HCl to give the corresponding (3-oxobutyl) aminophenyl derivatives. The electronic absorption and fluorescence spectra were studied, and the absolute fluorescence quantum yields of the synthesized compounds were determined. A relationship between the position and intensity of the absorption bands and the electron-donor substituents was uncovered, and a substantial effect of the nature of the solvent on the fluorescent spectra was established.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 116–120, January, 1976.     

Synthesis of carbohydrate-functionalized thiophene-capped cyclopenta[c]thiophene for concanavalin A recognition

Synthetic route to two different carbohydrate-functionalized oligothiophenes comprising central cyclopenta[c]thiophene (CPT) moiety was demonstrated. Turbidimetric analysis revealed enhanced interaction for divalent α-mannose-functionalized terthiophene 7 with Con A. The extent of binding interaction for 7-Con A complex formation was determined from isothermal titration calorimetry (ITC) measurements and the binding constant found (K_ITC) 2.4(6) × 10⁵ M^?1.     

Synthesis of 2H-pyrano[2,3-b]quinolines. Part II. Preparation and 1H-nmr investigations of 4-hydroxy-2-methyl-3,4-dihydro-2H-pyrano[2,3-b]quinolines

Diastereoisomers of 4-hydroxy-2-methyl-3,4-dihydro-2H-pyrano[2,3-b]quinolines 8 and 9 were synthesized starting from the appropriate 2-chloroquinoline-3-carboxaldehydes 1. The relative configuration of the 1,3-diol intermediates 4 and 5 was determined on the basis of the ¹³C-nmr spectra of their acetonides. The relative stereochemistry of title compounds was confirmed by using homonuclear NOE and selective decoupling experiments, as well as by analysis of the coupling patterns observed in their ¹H-nmr spectra.     

Pyrimido[5,4-b]quinolines. I. Synthesis of substituted tricyclic systems related to riboflavin

Two alternative synthetic routes were investigated for the synthesis of 2,4,10-substituted-7,8-dimethylpyrimido[5,4-b]quinolines: (1) cyclization of 5-(3,4-xylidino)-2,4-disubstituted-pyrimidine-6-carboxylic acids, and (2) cyclization of N-5-(2,4-disuhstituted-pyrimidinyl)-4,5-dimethylanthranilic acids. Route (1) invariably led to isomeric mixtures of the corresponding 7,8- and 8,9-dimethylpyrimido[5,4-b]quinolines which were difficult to separate, while route (2) yielded only the desired 7,8-dimelhyl derivatives. The required intermediates were synthesized by Ullman-type condensation of the appropriate pyrimidine and benzene derivatives. Cyclization with polyphosphoric acid, or phosphorus oxychloride (under various conditions) led to a number of new pyrimido[5,4-b]quinoline derivatives, with oxo, methoxy and/or chloro substituents in the 2,4 and 10 positions. A mild, but effective chlorination procedure was developed for the chlorination of the 10-(oxo) position without the cleavage of methoxyl groups at positions 2 and 4.     

Cycloaddition reactions of N-p-toluenesulfonylimino derivatives of quinoline and isoquinoline. A route to pyrazolo[1,5-a]quinolines and pyrazolo[5,1-a]isoquinolines

N-p-Toluenesulfonylimino ylides of quinoline and isoquinoline give cycloadducts with electrophilic acetylenes at 105°. The adducts are spontaneously aromatized under the conditions of their formation by elimination of p-toluenesulfmic acid to give pyrazolo[1,5-a]quinolines and pyrazolo[5,1-a]isoquinolines, respectively. The orientation of cycloaddition is the same as for N-amino ylides for acetylenic esters. The ad-ducts from p-nitrophenylacetylene are formed by addition of the imino nitrogen to the unsubstituted acetylenic carbon. The orientation and unreactivity of phenylacetylene indicate that the cycloaddition is controlled by dipole HOMO-dipolarophile LUMO interactions.     

Approaches to the synthesis of benzo[c]phenanthridines

6-Methylbenzo[c]phenanthridine derivatives were synthesized via an established route and their cytotoxic activity determined. Attempts to synthesize benzo[c]phenanthridines lacking the 6-methyl group via a 2-ben-zopyrylium intermediate were unsuccessful.     

Synthesis of functionally substituted benzo[c]pyrylium salts

Benzo[c]pyrylium salts that contain an acetyl, cyano, or ethoxycarbonyl group in the 4 position of the pyrylium ring were synthesized by the reaction of 3-(3,4-dimethoxyphenyl)pentane-2,4-dione and -(3,4-dimethoxyphenyl)acetoacetonitrile and ethyl -(3,4-dimethoxyphenyl)acetoacetate, as well as ethyl -(3,4-dimethoxyphenyl)benzoylacetate, with acyl perchlorates. It is shown that -(3,4-dimethoxyphenyl)acetoacetonitrile ethyleneketal is converted to 3-amino-4-acetylbenzo(c)pyrylium salts under these conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 465–470, April, 1990.     

Synthesis, characterization, and structure of cyclopenta[c]thiophenes and their manganese complexes

1,3-Diaryl-4H-cyclopenta[c]thiophenes are efficiently prepared from 1,2-diaroylcyclopentadienes by use of Lawesson's reagent. eta5-Cyclopenta[c]thienyl complexes, [Mn(eta5-SC7H3-1,3-R2)(CO)3] (R = Me, Ph), are prepared in high yield by ligand substitution reactions of [MnBr(CO)5] with [SnMe3(SC7H3-1,3-R2)]. Alternatively, thiation with P4S10/NaHCO3 converts [Mn{eta5-1,2-C5H3(COR)2)(CO)3] to [Mn(eta5-SC7H3-1,3-R2)(CO)3] (R = Ph, 4-tolyl, 4-MeOC6H4, benzo[2,3-b]thienyl). The molecular structures of complexes with R = Me, Ph show planar eta5-cyclopenta[c]thienyl ligands, with the manganese atom slightly displaced away from the ring-fusion bond.     

Synthesis and reactions of methylbenzo[c]quinolizinium salts

Six isomers of the methylbenzo[c]quinolizinium salt 3 including four new monomethyl derivatives were synthesized by thermal-intramolecular quaternization of the cis-methyl-substituted 2-[2-(2-chlorophenyl)-vinyl]pyridines 4 or by the irradiation of trans- 4 with selected wavelengths (290 < λ < 340 nm and λ > 400 nm) in acetonitrile. Among the regioisomeric monomethyl derivatives 3 , the 1-, 3-, and 6-methyl derivatives 3b, 3d , and 3g reacted with p-methoxybenzaldehyde in the presence of bis(l-piperidino)-(p-methoxyphenyl)-methane 7 to yield trans-(p-methoxystyryl)benzo[c]quinolizinium salts 6 . The reactivity of 3 and methylbenzo[a]quinolizinium salts 1 was discussed on the basis of their π-electron energy.     

Spectral studies of some substituted arylthiobenzo[f]quinolines

Synthesis and spectral studies (ir, ¹H nmr, ms) of 1- and 3-substituted arylthiobenzo[f]quinolines (IIIa-IIIc, IVa-IVc) obtained through nucleophilic displacement of the corresponding halobenzo[f]quinoline by various thiols (a-c) were done.     

Microwave-assisted synthesis of substituted hexahydro-pyrrolo[3,2-c]quinolines

New compounds with the ethyl hexahydro-1H-pyrrolo[3,2-c]quinoline-2-carboxylate skeleton were prepared by microwave-assisted intramolecular 1,3-dipolar cycloaddition reactions. The reactions were carried out under solvent-free conditions and compared with the same reaction in the presence of a solvent and a catalyst. Steric effects on the selectivity of the reaction were noted and evaluated.