Efficient synthesis of novel tetrahydropyrrolo[3′,4′:3,4]pyrrolo[2,1-a] isoquinoline derivatives via a simple and convenient MCR in aqueous micellar system (original) (raw)
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A new approach towards the synthesis of pyrrolo[2,1- a]isoquinolines
Tetrahedron Letters, 2010
Reaction of 5-bromo-2-methyl-8-nitro-1,2,3,4-tetrahydroisoquinoline with activated alkynes affords stable tetrahydropyrrolo[2,1-a]isoquinolin-4-ium ylides. Further reactions of ylide 2 gives access to substituted dihydropyrrolo[2,1-a]isoquinolines in good yields.
ACS Omega
An efficient and quick access toward a series of (E)-2-arylideneaminopyrroles 6 and to their benzyne-promoted aza-Diels−Alder cycloaddition products is provided. These products are three pyrrolo[2,3-c]isoquinolines 8a−c substituted in position 5 with different electron-acceptor (A) or electron-donor (D) aryl groups. Intermediates and products were obtained in good yields (up to 78 and 84%, respectively), and their structures were determined on the basis of NMR measurements and HRMS analysis. Photophysical properties of 8a−c were investigated, finding good Stokes shift in different solvents, but only the product 8c showed appreciable fluorescence intensity since its 5-aryl group (2,4-Cl 2 Ph) could favor the twisted intramolecular charge transfer effect. In addition, a riveting relationship between solvent viscosity and fluorescence intensity was found. Structures of 6 and 8 were studied and confirmed by single-crystal X-ray diffraction, observing that their electronic distributions effect the supramolecular assembly but with only long-distance hydrophobic interactions. A CE-B3LYP model was used to study the energetic topology and understand the crystal architecture of compounds as well as find a connection with both the synthetic and photophysical results.
Chinese Chemical Letters, 2013
Tandem CC bond formations are powerful methods for the rapid, elegant and convenient construction of complex organic molecules from relatively simple starting materials in a straightforward way [1-11]. These transformations are usually operated in one-pot reactors without the need for intermediate workups or purifications. In particular, the development of tandem reactions for the efficient construction of complex molecules is an important goal in combinatorial chemistry from the viewpoints of operational simplicity and assembly efficiency. The rich and fascinating chemistry that stems from the addition of nucleophiles to activated acetylenic compounds has evoked considerable interest. N-heterocycles are known to form zwitterions with activated acetylene compounds, such as dimethyl acetylenedicarboxylate [12-14]. These zwitterions can be trapped by a variety of electrophiles and proton donors, which is a novel protocol for the synthesis of heterocyclic compounds [12-16]. Recently, our research group was involved in various multicomponent reactions that can provide easy access to important heterocyclic systems [16,17]. We now report the results of our studies involving the reactions of zwitterions derived from isoquinoline 1 and dialkyl acetylenedicarboxylates 2 in the presence of dialkyl chloromalonate (3), which constitutes a synthesis of hexaalkyl benzoisoquinolinopyrrolonaphthyridinehexacarboxylate 4a-f in good yields (Scheme 1). 2. Experimental The reagents and solvents in this work were obtained from Aldrich and Fluka and were used without further purification. The analytical equipment included: mp, Electrothermal-9100 apparatus. IR spectra (KBr, cm À1), Shimadzu IR-460 spectrometer; in cm À1. 1 H NMR and 13 C NMR spectra, Bruker DRX-300 Avance instrument; in CDCl 3 at 300 and 75 MHz, respectively; d in ppm, J in Hz. MS, Finnigan-MAT-8430 mass spectrometer, at 70 eV; in m/z (rel.%). Elemental analyses (C, H, N), Heraeus CHN-O-Rapid analyzer. General procedure for the preparation of compounds 4: To a stirred solution of 2 (2 mmol) and 3 (2 mmol) in 10 mL of CH 2 Cl 2 was added 0.24 mL of isoquinoline (2 mmol) dropwise at À10 8C over 5 min. The reaction mixture was then allowed to warm to room temperature and stand for 12 h. The solvent was removed under reduced pressure, and the residue was purified by silica gel (Merck 230-240 mesh) column chromatography using n-hexane/ EtOAc (3:1) mixture as eluent to afford the pure product.
A Versatile Cyclodehydration Reaction for the Synthesis of Isoquinoline and β-Carboline Derivatives
Organic Letters, 2008
The direct conversion of various amides to isoquinoline and β-carboline derivatives via mild electrophilic amide activation, with trifluoromethanesulfonic anhydride in the presence of 2chloropyridine, is described. Low temperature amide activation followed by cyclodehydration upon warming provides the desired products with short overall reaction times. The successful use of nonactivated and halogenated phenethylene derived amides, N-vinyl amides, and optically active substrates are noteworthy. The venerable Bischler-Napieralski reaction offers an important strategy for the synthesis of various azaheterocycles. 1,2 Isoquinolines and β-carbolines, including their reduced derivatives, can be found as substructures in many important natural products, pharmaceuticals, and other fine chemicals. 3 We have reported the syntheses of pyridine 4a and pyrimidine 4b derivatives via the intermolecular condensation of readily available N-vinyl and N-aryl amides 5 with various nucleophiles. Herein we report mild reaction conditions for the Bischler-Napieralski based synthesis of isoquinoline and β-carboline derivatives from readily available amides. During our studies concerning the syntheses of pyridines and quinolines via an intermolecular condensation reaction 4b we observed a competitive intramolecular cyclization reaction in a single case where a Morgan-Walls 6 cyclization pathway was possible. N-Phenethylbenzamide (1 , Table 1) was used to further investigate this intramolecular condensation reaction. Consistent with our observations on amide activation for the intermolecular addition of σor π-nucleophiles, 4 the use of trifluoromethanesulfonic anhydride (Tf 2 O
Tetrahedron Letters, 2006
Isoquinoline reacts with ethyl bromopyruvate in the presence of dialkyl acetylenedicarboxylates or diaryloylacetylenes to produce dialkyl 1-(2-ethoxy-2-oxoacetyl)pyrrolo[2,1-a]isoquinoline-2,3-dicarboxylates or ethyl 2-[2,3-diaryloylpyrrolo[2,1-a]isoquinoline-1-yl]-2-oxoacetates in good yields. Tetrahedron Letters 47 (2006) 6037-6040 3 J HH = 7.2 Hz, CH 3 ), 3.90 (3H, s, OCH 3 ), 3.93 (3H, s, OCH 3 ), 4.36 (2H, q, 3 J HH = 7.2 Hz, OCH 2 ), 7.14 (1H, t, 3 J HH = 7.2 Hz, CH), 7.47 (1H, t, 3 J HH = 7.2 Hz, CH), 8.47 (1H, d, 3 J HH = 7.3 Hz, CH), 9.51 (1H, d, 3 J HH = 7.2 Hz, CH) ppm. 13 C NMR (125.7 MHz, CDCl 3 ): d = 14.0 (CH 3 ), 52.2 (OCH 3 ), 52.7 (OCH 3 ),
The Journal of Organic Chemistry, 2005
The stereoselective outcome of Pd(II)-or Ag(I)-catalyzed intramolecular N-alkylation to afford 1,3disubstituted 1,2,3,4-tetrahydroisoquinolines was examined. In the absence of additional substituents, Pd(II) allows a facile access to the cis isomers, while Ag(I) favors formation of the trans isomers. The same observation was made for the synthesis of 2,5-disubstituted pyrrolidines.