Synthesis of 2-spiro-(1,2-dihydroperimid-2-yl)-5,5-dialkyl-2,3,5,6-tetrahydropyrrolo[2,1-a]-isoquinolin-3-ones

2,3-Dioxpyrrolo[2,1-a]isoquinolines react with 1,8-naphthalenediamine in 2-propanol in the presence of p-toluenesulfonic acid to give 2-spiro-(1,2-dihydroperimid-2-yl)-5,5-dialkyl-2,3,5,6-tetrahydro-pyrrolo[2,1-a]isoquinolin-3-ones whose structure was confirmed by X-ray analysis. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1849–1854, December, 2008.     

A one-pot conversion of ortho-alkynyl benzaldehydes into indolo[2,1-a]isoquinolines

The conversion of readily available 2-halobenzaldehydes into indolo[2,1-a]isoquinolines in two operations represents a very direct entry to this class of molecules.     

Synthesis of dihydrobenzoimidazo[2,1-a]isoquinolines

A one-pot protocol toward several substituted 5,6-dihydrobenzo[4,5]imidazo[2,1-a]isoquinolines 1 starting with 2-allylbenzaldehydes 2 was described. The process was carried out the one-pot condensation/hydroamination reaction of substituted 2-allylbenzaldehydes 2 with 1,2-diaminobenzenes 3 in refluxing toluene in good yields. Skeleton 2 was prepared via one-pot ortho-metalative PhBCl₂-mediated double alkylation of hydroxybenzaldehyde 4 with LDA in moderate yields.     

One-pot two-step tandem reactions for selective synthesis of pyrrolo[2,1-a]isoquinolines and dihydro-, tetrahydro-derivatives

A sequential one-pot two-step tandem reaction for selective and efficient synthesis of pyrrolo[2,1-a]isoquinoline and its dihydro- and tetrahydro-derivatives has been developed. The tandem reactions of isoquinoline, α-halogenated methylene compounds, aromatic aldehydes, and cyanoacetamide firstly give tetrahydropyrrolo[2,1-a]isoquinolines as main products. The corresponding pyrrolo[2,1-a]isoquinolines and dihydropyrrolo[2,1-a]isoquinolines can be obtained directly by controlling oxidation with DDQ. The mechanism of this tandem reaction involved the 1,3-dipolar cycloaddition of isoquinolinium ylide as the key step. A unique elimination of the amido group preferring to the cyano group has been observed.     

Formylation of Furyl-substituted Imidazo[1,2-a]pyridine, Imidazo[1,2-a]pyrimidine and Imidazo[2,1-b]thiazole

Vilsmeier formylation of 2-(2-furyl)-substituted imidazo[1,2-a]pyridine and imidazo[1,2-a]pyrimidine, and also 6-(2-furyl)imidazo[2,1-b]thiazole with 1 mole of reagent occurs at the free position of the imidazole ring, while with an excess of the reagent it also occurs at the position 5 of the furyl group.     

Multicomponent reactions of pyridines, α-bromo carbonyl compounds and silylaryl triflates as aryne precursors: a facile one-pot synthesis of pyrido[2,1-a]isoindoles

Multicomponent reactions (MCRs) involving pyridines, α-bromo ketones, and silylaryl triflates as aryne precursors were investigated. The reactions could also be extended to isoquinoline or α-bromo ethyl acetate. Substituted pyrido[2,1-a]isoindoles or isoindolo[2,1-a]isoquinolines could be obtained from this routine, which may have potential applications in antitumor drugs and fluorescent material fields.     

Reactions of 2,3-Dioxopyrrolo[2,1-a]isoquinolines with Ammonia and Aliphatic Amines

2,3-Dioxopyrrolo[2,1-a]isoquinolines, with either a tertiary amide substituent at position 1 or no substituent, react with ammonia and aliphatic amines with ring opening to form the corresponding enamino keto amides.     

Cycloaddition in Condensed Isoindoles. 2. Method for Obtaining New Derivatives of 2-Phenylpyridine

The reaction of pyrido[2,1-a]isoindole with maleimide derivatives has been investigated. A new rearrangement has been found, the products of which are 2-[2'-(1-R-2,5-dioxopyrrolidinidene)-2'-(1-R-2,5-dioxopyrrolidinyl)methyl]phenylpyridines. A probable mechanism for the rearrangement has been proposed. The existence of atropoisomerism for the compounds obtained has been demonstrated by ¹H NMR spectra.     

Sulfur ylides 15. Intramolecular cyclization of new keto-stabilized sulfur bis-ylide

New sulfur bis-ylide was obtained from 3-amino-3-phenylpropionic acid and pyromellitic dianhydride. Its intramolecular cyclization proceeds regioselectively, leading to 3,4,11,12-tetrahydro-2H,6H-indolizino[2,1-f]pyrido[2,1-a]isoindole derivative in 66% yield. Phosphorus bis-ylide of similar structure gives a cyclization product in 10% yield. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2394–2396, December, 2007.     

Dipyrrolo[1,2-a:2',1'-c]pyrazines. 8. Electrophilic Substitution in Dipyrrolo[1,2-a:2',1'-c]pyrazines and 5,6-Dihydrodipyrrolo[1,2-a:2',1'-c]pyrazines. Acylation of Dipyrrolo[1,2-a:2',1'-c]pyrazines

Esters, nitriles, and amides of dipyrrolo[1,2-a:2',1'-c]pyrazines have been synthesized by the acylation of dipyrrolo[1,2-a:2',1'-c]pyrazines and 5,6-dihydrodipyrrolo[1,2-a:2',1'-c]pyrazines with trichloroacetic acid chloride, p-tosyl isocyanate, and isocyanatophosphoric acid dichloride (Kirsanov isocyanate).     

7,8,9,10-Tetrahydropyrrolo[2,1-a]isoquinolines in the search for new indolizine derivatives

7,8,9,10-Tetrahydropyrrolo[2,1-a]isoquinolines were obtained by 1,3-dipolar cycloaddition reactions of their corresponding N-ylides with olefinic (acrylonitrile) and symmetrical or non-symmetrical acetylenic dipolarophiles (methyl/ethyl propiolate, dimethyl acetylenedicarboxylate). Also, stable 5,6,7,8-tetrahydroisoquinolinium dicyanomethylide was isolated and characterized by X-ray diffraction analysis.     

Solvent-free reaction between acenaphthoquinone, various benzils and ammonium acetate: synthesis of 9,10-diaryl-7H-benzo[d,e]imidazo[2,1-a]isoquinolin-7-ones

A simple synthesis of benzo[d,e]imidazo[2,1-a]isoquinolines is described. Heating a mixture of acenaphthoquinone, a benzil, and ammonium acetate under solvent-free conditions afforded 9,10-diaryl-7H-benzo[d,e]imidazo[2,1-a]isoquinolin-7-ones in good to excellent yields.     

Alkylation of 2,3,6,11-tetrahydroanthra[2,1-d]isothiazole-3,6,11-trione and its S-oxide

The reactions of 2,3,6,11-tetrahydroanthra[2,1-d]isothiazole-3,6,11-trione with dimethyl sulfate, benzyl chloride, and allyl bromide afforded the corresponding 2-alkyl-2,3,6,11-tetrahydroanthra[2,1-d]isothiazole-3,6,11-triones and 3-(alkoxy)-6,11-dihydroanthra[2,1-d]isothiazole-6,11-diones. The reactions of 2,3,6,11-tetrahydroanthra[2,1-d]isothiazole-3,6,11-trione and its S-oxide with a formaldehyde—secondary amine system yielded 2-[(alkylamino)methyl]-2,3,6,11-tetrahydroanthra[2,1-d]isothiazole-3,6,11-triones and 2-[(alkylamino)methyl]-3,6,11-trioxo-2,3,6,11-tetrahydroanthra[2,1-d]isothiazole 1-oxides, respectively.     

An AB + D → ABCD approach to the construction of the 8-azasteroid skeleton by [3+3] cyclocondensation of 3,4-dihydroisoquinolines with ethyl 2-oxocyclopentanecarboxylate as a new annelation reaction for a series of cyclic Schiff"s bases

A new approach (AB + D ABCD) to the construction of tetracyclic 8-azagonane (cyclopenta[5,6]pyrido[2,1-a]isoquinoline or benzo[a]cyclopenta[f]quinolizine) structures was developed and exemplified by cyclocondensation of 1-alkyl-3,4-dihydroisoquinolines with ethyl 2-oxocyclopentanecarboxylate.     

Synthesis of the dibenzopyrrocoline alkaloid skeleton: indolo[2,1-a]isoquinolines and related analogues

The indolo[2,1-a]isoquinoline and pyrrolo[2,1-a]isoquinoline nuclei have been synthesized from N-benzylindole or ethyl 1H-indol-1-ylacetate and N-benzylpyrrole precursors, respectively. Firstly, at C-2 of either the indole or pyrrole nucleus, aromatic rings containing a carbonyl substituent ortho to the newly formed biaryl axis were introduced using the Suzuki-Miyaura coupling reaction. Thereafter, under basic conditions the nucleophile that formed at the acidic methylene protons of the N-benzylindole, ethyl 1H-indol-1-ylacetate or N-benzylpyrrole intermediate reacted with the internal aromatic carbonyl to yield (after the expulsion of water) the title compounds. For example, exposure of ethyl 2-(2-(2-formylphenyl)-1H-indol-1-yl)acetate to potassium tert-butoxide resulted in the formation of ethyl indolo[2,1-a]isoquinoline-6-carboxylate.     

Synthesis of substituted benzimidazo[2,1-a]isoquinolines and its condensed analogues using Pd(0)-catalyzed cyclization/C-H activation

An efficient route for the synthesis of benzimidazo[2,1-a]isoquinolines and its condensed analogues has been developed via the palladium-catalyzed cyclization/C-H activation of N-allyl and N-methallyl derivatives of benzimidazoles.     

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.     

Synthesis and study of the mutagenic activity of di(indeno[2,1-b]indolyl)- and di(indeno[2,1-b]pyrrolyl)methanes and -dimethylsilanes

Dihetaryldimethylsilanes and dihetarylmethanes containing indeno[2,1-b]indolyl and indeno[2,1-b]pyrrolyl fragments were synthesized. Their mutagenic activity was tested according to Ames with standard test strains Salmonella typhimurium TA 1537, TA 98, and TA 100.     

Palladium-catalyzed carbonylative synthesis of indoloisoindoloquinazolinone derivatives by using CO as a carbonyl source

An efficient synthesis of indolo[1,2-c]isoindolo[2,1-a]quinazolin-5(16aH)-one derivatives through palladium-catalyzed cyclocarbonylation reaction of 6-(2-bromoaryl)-5,6-dihydroindolo[1,2-c]quinazolines with the use of CO as a carbonyl source under atmospheric pressure has been disclosed. More intriguingly, the above-mentioned products can also be obtained directly from a one-pot two-step tandem reaction of 2-(1H-indol-2-yl)anilines and 2-bromobenzaldehydes, which are the precursors of 6-(2-bromoaryl)-5,6-dihydroindolo[1,2-c]quinazolines, under an atmospheric CO pressure in modest yields.     

Synthesis and structure of some thienopyrimidine derivatives

A series of substituted thieno[2,3-d]pyrimidines was synthesized starting from ethyl-2-amino-4-isopropylthiophene-3-carboxlate. Reaction of 2-hydrazino-5-isopropyl-thieno[2,3-d]pyrimidin-4(3H)-one and its 3-methyl analogue with different reagents afforded thieno[2,3-d]triazolo[4,3-a]pyrimidines and thieno[3,2-e]triazolo[4,3-a]pyrimidines, beside open chain derivatives. Correspondence: Atef A. Hamed, Department of Chemistry, Faculty of Science, Menoufia University, Shebin El Koam, Egypt.