Efficient One-pot Synthesis of Pyrrolo[2,1-a]isoquinoline and Pyrrolo[1,2-a]quinoline Derivatives

A one-pot sequential reaction for efficient synthesis of pyrrolo[2,1-a]isoquinoline and pyrrolo[1,2-a]-quinoline derivatives has been developed. The reaction included firstly the Cu-catalyzed three-component reaction of isoquinoline(quinoline), acetylenedicarboxylate and alkynylbenzene and then Cs₂CO₃-promoted intramolecular cyclization reaction of initially formed 1-alkenyl-2-alkynyl-1,2-dihydroisoquinoline(1,2-dihydroquinoline).     

Generation of pyrrolo[2,1‐a]isoquinoline derivatives from N‐ylides: Synthetic control and structural characterization

New pyrrolo[2,1‐a]isoquinolines were obtained by two one‐pot procedures via 1,3‐dipolar cycloaddition between the isoquinolinium N‐ylides and symmetrical acetylenic dipolarophiles, avoiding the formation of dihydro intermediates. For structural comparison, the dihydro derivatives obtained by a classical two‐stage reaction were characterized by NMR and X‐ray crystallography, allowing complete stereochemistry assignments. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:723–729, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/.20740     

Efficient Synthesis of Pyrrolo[2,1‐a]isoquinoline and Pyrrolo[1,2‐a]quinoline Derivatives via One‐pot Two‐step Metal‐catalyzed Three‐component Reactions

A sequential one‐pot two‐step reaction for efficient synthesis of pyrrolo[2,1‐a]isoquinoline and pyrrolo[1,2‐a]quinoline derivatives in good yields has been successfully developed. The reaction included firstly Cu‐catalyzed three‐component reaction of isoquinoline (quinoline), acetylenedicarboxylate and alkynylbenzene and then Pd‐catalyzed intramolecular C(sp)‐C(sp²) coupling reaction of initially formed 1‐alkenyl‐2‐alkynyl‐1,2‐dihydroisoquinoline (1,2‐dihydroquinoline).     

Modular synthesis of pyrrolo[2,1‐b]thiazoles and related monocyclic pyrrolo structures

A modular synthesis of selectively‐substituted pyrrolo[2,1‐b]thiazoles (Δ⁶ isomeric form) has been implemented, involving a distinctive bicyclization reaction of a mucobromic acid derivative followed by a Suzuki‐Miyaura coupling. A novel process of Δ⁶ to Δ⁷ isomerization of the pyrrolothiazole structure was uncovered that appears to involve a 1,4‐addition‐1,2‐elimination mechanism. Preparation of 1,5‐dihydropyrrol‐2‐one structures, selectively substituted at the 3‐ and 4‐positions, was also achieved using the mucobromic acid synthon in a reductive amination process. J. Heterocyclic Chem., (2011).     

Synthesis of pyrrolo[2,1-a]isoquinoline hydrazones and oximes

Reactions between 2,3-dioxopyrrolo[2,1-a]-isoquinolines and hydrazines and hydroxylamine afforded the corresponding hydrazones and oximes.Institute of Applied Chemistry, Urals Branch, Russian Academy of Sciences Perm' 614600. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 934–937, July, 1995. Original article submitted May 5, 1995.     

Carbazolo[2,1‐a]carbazole derivatives via fischer indole synthesis

A series of new carbazolo[2,1‐a]carbazoles was synthesized from 4‐oxo‐1,2,3,4‐tetrahydrobenzo[a]‐carbazole derivatives.     

Novel route for the synthesis of structurally diverse pyrrolo[2,1-a]isoquinoline in aqueous micellar medium

A high yielding environmentally benign protocol has been developed for the synthesis of pyrrolo[2,1-a]isoquinoline using chromone-3-carboxaldehyde, isoquinoline and phenacyl bromide/bromoacetic acid ester as reagents in aqueous micellar medium. The method is operationally simple and more effective compared to the previous methods in terms of the yield of the products as well as the reaction time.     

Facile synthesis of pyrrolo[2,1‐c][1,4]benzodiazepine‐5,11‐dione dimer

Efficient synthesis of biological important pyrrolo[2,1‐c][1,4]benzodiazepine‐5,11‐dione dimer linked through the C‐2 positions by fumarate group is described.     

Electronic spectra of pyrrolo[2,1-a]isoquinolines and pyrrolo[1,2-f]phenanthridines

The electronic absorption spectra of dioxo-compounds of the pyrroto[2,1-a]isoquinoline and pyrrolo[1,2-f]phenanthridine series and products of their condensation with o phenylenediamine were studied. The influence of substituents was demonstrated; halochromic phenomena in sulfuric acid medium were described; the fluorescence spectra are discussed.Institute of Technical Chemistry, Urals Branch of the Russian Academy of Sciences, Perm' 614600. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 650-653, May, 1995. Original article submitted March 14, 1995.     

Microwave-assisted combinatorial synthesis of polysubstituent imidazo[1,2-a]quinoline, pyrimido[1,2-a]quinoline and quinolino[1,2-a]quinazoline derivatives

A series of unusual fused heterocyclic compound derivatives, consisting of a pyridine and a imidazole or pyrimidine core, with a bridgehead nitrogen, were successfully synthesized by a microwave-assisted, three-component domino reaction of aldehydes, enaminones, and malononnitrile. In this one-pot reaction, up to five new bonds were formed accompanied by generating the lactam group. This method has the advantages of short synthetic route, operational simplicity, increased safety for small-scale high-speed synthesis, and minimal environment impact.     

Asymmetric synthesis of pyrrolo[2,1-a]isoquinoline derivatives by 1,3-dipolar cycloadditions of stabilized isoquinolinium N-ylides with sulfinyl dipolarophiles

Enantiomerically pure pyrrolo[2,1-a]isoquinoline derivatives are obtained by 1,3-dipolar reactions of isoquinolinium azomethine ylides with enantiopure 3-p-tolylsulfinylacrylonitriles, tert-butyl (2E)-4,4-diethoxy-2-p-tolylsulfinylbut-2-enoate, and 5-ethoxy-3-p-tolylsulfinylfuran-2(5H)-ones. Reactions evolve through the anti conformation of the ylide with complete regioselectivity. The facial selectivity is completely controlled by the configuration of the sulfinyl sulfur for acyclic dipolarophiles, whereas it is high (dr 83/17 or 89/11) but controlled by the C-5 configuration for sulfinylfuranones. Complete endo selectivity is observed with cyclic dipolarophiles and substituted acrylonitriles, but it is low with butenoate. The sulfinyl group also exerts a positive influence on the dipolarophilic reactivity toward these ylides.     

Rearrangement of spiro[2H‐1‐benzopyran‐2,2′‐[2H]indoles] to pyrrolo[1,2‐a]indole derivatives

Heating of 1′‐(N‐substituted carbamoyl)methylspiro[2H‐1‐benzopyran‐2,2′‐[2H]indoles] with potassium hydroxide in ethanol yields diastereomeric 5a,13‐methano‐6H‐1,3‐benzoxazepino[3,2‐a]indole‐12‐carbox‐amides. Reduction of the latter with sodium borohydride affords 1,2,3,9a‐tetrahydro‐2‐hydroxyaryl‐9H‐pyrrolo[ 1,2‐a] indole‐3 ‐carboxamides.     

A facile synthesis of pyrrolo[1,2-a]pyrimidines and pyrrolo[1,2-a]imidazoles

The one-step synthesis of 8-t-butoxycarbonyl-6,7-dimethyl-2-oxo-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrimidine from acetyl methyl carbinol, 3-aminopropionic acid, and t-butyl cyanoacetate is reported. Utilizing a similar technology under basic conditions, 7-substituted 5,6-dimethyl-2-oxo-2,3-dihydro-(1H)-pyrrolo[1,2-a]imidazole is synthesized from acetyl methyl carbinol, ethyl glycinate, and the appropriate acetonitrile.     

Synthesis of isoquinoline derivatives of quinoxalin-2-one from pyrrolo[2,1-a]isoquinoline-2,3-diones and o-phenylenediamine

Reactions of 5,5-dialkyl-2,3,4,5-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-diones with o-phenylenediamine in the presence of a catalytic amount of hydrogen chloride or p-toluenesulfonic acid involved opening of the pyrrole ring with formation of 3-(3,3-dialkyl-1,2,3,4-tetrahydroisoquinolin-1-ylidenemethyl)quinoxalin-2(1H)-ones. The presence of an enamine fragment in the products was confirmed by reaction with oxalyl chloride.