Search

An easy synthesis of novel highly functionalized 5,6-dihydroindolo[2,1-a]isoquinolines was developed via a pseudo four-component domino reaction of 1-aroyl-3,4-dihydroisoquinolines, terminal α,β-ynones, and malononitrile. The selective formation of this biologically relevant heterocyclic core was achieved using a one-pot approach under microwave irradiation. The formation of the same skeleton through the reaction of 5,6-dihydropyrrolo[2,1-a]isoquinolines with malonic acid dinitrile supports the proposed mechanism, involving the intermediate product of the three-component reaction. Furthermore, the disproval of an alternative reaction pathway, which involved the dimerization of malononitrile followed by three-component transformation, was demonstrated. Introducing the malononitrile dimer as a CH acid resulted in the formation of a different pyrido[3′,4′:4,5]pyrrolo[2,1-a]isoquinoline core. Additionally, the synthesized 5,6-dihydroindolo[2,1-a]isoquinolines were examined for their photophysical properties, revealing their attractive luminescent characteristics.

Adducts of 1-alkyl-2-imidazolines and two molecules of alkyl propiolate, possessing an N-propargyl-β-enaminoester fragment, easily undergo a domino reaction to form pyridinium salts with β-(alkylammonio)ethyl group at the nitrogen atom in the presence of 2 equiv of a protic acid. Treatment of the above reaction mixture with a base gives 1,2,3,8a-tetrahydroimidazo[1,2-a]pyridines. Reaction of the latter compounds with acid chlorides affords pyridinium salts with β-(alkylamido)ethyl moiety at the nitrogen atom.

An unprecedented electrochemical three-component reaction of phenylacetylene, sulfinate, and N-(formyl)anilide was discovered. The transformation occurs in an undivided cell with a graphite anode and cathode in DMF in the presence of tetrabutylammonium iodide as an electrolyte. The addition of silver(I) oxide and catalytic amounts of iodine facilitated the reaction significantly. The transformation was also carried out under photoredox-catalyzed conditions.

Interactions of N-(propargyl)indole-2-carbonitriles with nitrogen nucleophiles were studied. It was found that lithium hexamethyldisilazane (LiHMDS)-promoted reactions give mixtures of two product types, originating from an initial attack onto carbon–carbon or carbon–nitrogen triple bonds. Performing the reaction at reduced temperature and in the presence of catalytic amounts of LiHMDS delivered alkyne hydroamination products exclusively. On the contrary, the one-pot reaction of N-(propargyl)indole-2-carbonitriles with methanol and LiHMDS on heating, followed by the addition of a nitrogen nucleophile, allowed a selective domino cyclization sequence toward 1-aminopyrazino[1,2-a]indoles. Anilines and nitrogen heterocycles could be employed as N-nucleophiles to obtain products of both types. Moreover, an alternative one-pot route toward a third product type has been developed. When N-(propargyl)indole-2-carbonitrile was first combined with aniline and LiHMDS at reduced temperature, further heating of the in situ generated hydroamination product led to the intramolecular cyclization into 1-imino-2-phenylpyrazino[1,2-a]indoles. Thus, chemodivergent transformations of the same starting material into three compound classes were investigated. The possible reaction routes were studied, and N-(allenyl)indole-2-carbonitrile was identified as the key intermediate. Acyclic and cyclic products exhibit fluorescence emission in the blue to green range.

The transformation of 2-imidazolines into 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazines has been realized. A pseudo-three-component reaction of 2-imidazolines with terminal electron-deficient alkynes (2 equiv) first generates imidazolidines, containing an N-vinylpropargylamine fragment. The latter can then undergo a base-catalyzed domino aza-Claisen rearrangement/cyclization reaction sequence, simultaneously constructing pyrrole and pyrazine rings. The process works in a broad substrate scope, delivering pyrrolo[1,2-a]pyrazines in good to excellent yields (45–90%). This two-step approach can be carried out in a one-pot fashion without a noticeable decrease in yield. Remarkably, a three-component protocol for the introduction of two different alkynes has been also developed.

The reaction of 1,2-disubstituted 2-imidazolines with electron-deficient alkynes proceeds as a pseudo-three-component process and forms imidazolidines with an N-vinylpropargylamine fragment. Heating the resulting imidazolidines in xylene on air leads to an effective formation of polysubstituted pyrroles through a domino sequence of aza-Claisen rearrangement/transannular nucleophilic addition/oxidative ring opening reactions. The direct one-pot transformation of 2-imidazolines to pyrroles has been also realized.

A three component reaction employing readily available starting materials: 2‐(1‐pyrrolyl)benzylamine, arylglyoxal monohydrates and electron‐deficient alkenes in the synthesis of dipyrrolobenzo[1,2‐a: 2′,1′‐c][1,4]diazepines ‐ previously undescribed system and indolo[2,1‐c]pyrrolo[1,2‐a][1,4]benzodiazepine derivatives have been shown. Domino reactions of pyrrolo[1,2‐a][1,4]benzodiazepines with electron‐deficient alkenes has been proposed as another approach. The applicability of the three‐component reaction for the synthesis of indolizino[8,7‐b]indole derivatives from tryptamine has been studied. The in vitrobiological activity of title compounds has been tested. A series of novel dipyrrolobenzo[1,2‐a: 2′,1′‐c][1,4]diazepine derivatives has been prepared using domino‐reactions of pyrrolo[1,2‐a][1,4]benzodiazepines with electron‐deficient alkenes and viathree component reaction between 2‐(1‐pyrrolyl)benzylamine, arylglyoxal monohydrate and alkenes. Multicomponent approach has been applied in the synthesis of indolizino[8,7‐b]indole derivatives from tryptamine. The developed methods are simple and convenient procedures giving medium and excellent yields, showing a wide functional group tolerance.

(Het)Arylallenes undergo hydrosulfonylation under photoredox-catalyzed conditions. The reaction gives vinyl sulfones in a regio- and diastereoselective manner, employing sodium sulfinates as the sulfonyl source and eosin Y as the photocatalyst. Indol-1-yl, pyrrol-1-yl, phenyl, and naphtylallenes might be used. Aliphatic allenes are incompatible with the reaction conditions.

Electrolysis of o-alkynyl-N-(formyl)anilides and sodium sulfinates on graphite electrodes delivers biologically sound 3-(sulfonyl)quinol-4-ones with moderate to good yields. The reaction is carried out in an undivided cell in the presence of silver(I) oxide with potassium iodide or sodium tetrafluoroborate as the supporting electrolyte. The reaction tolerates variously substituted anilides as well as aryl and alkyl sulfinates. The transformation proceeds as a domino sequence of oxysulfonylation and cyclocondensation steps.

1-(Propargyl)indol-2-carbonitriles react with alcohols to afford 1-alkoxypyrazino[1,2-a]indoles under DBU-catalyzed microwave-assisted conditions. The reaction scope includes a wide range of indoles, primary and secondary alcohols, and a thiol. The initial mechanistic study shows that the domino process presumably proceeds through an alkyne–allene rearrangement, imidate formation, and nucleophilic cyclization reaction sequence.

Aim and Objective: A new approach to synthesis of isoindoles condensed with other heterocycles and revelation of their spatial structure for biochemistry purposes was the main objective of this research. Material and Method: Starting materials for the proposed method, 1-furyl substituted pyrrolo[1,2-a]pyrazines, pyrrolo[1,2-a][1,4]diazepines and their benzoannulated analogues - 4-furyl substituted pyrrolo[1,2-a]quinoxalines and pyrrolo[1,2-a][1,4]benzodiazepines, were synthesized by known procedures. These compounds, all containing a furfurylamine moiety, were introduced into the tandem acylation/ intramolecular furan Diels-Alder (IMDAF) reaction with α,β-unsaturated acid anhydrides (maleic and itraconic anhydrides). In most cases, the key step - the IMDAF reaction - proceeds diastereospecifically with simultaneous formation of five new stereogenic centers and affording the title compounds in mild conditions with satisfactory overall yields. Results: Consequently a broad series of 10,12a-epoxypyrrolo[2',1':3,4]pyrazino[2,1-a]isoindoles, 11,13a-epoxypyrrolo[ 2',1':3,4][1,4]diazepino[2,1-a]isoindoles, tetrahydro-14bH-12,14a-epoxyisoindolo[2,1-a]pyrrolo[2,1-c]quinoxalines, and tetrahydro-9H,15bH-13,15a-epoxyisoindolo[1,2-c]pyrrolo[1,2-a][1,4]benzodiazepines was synthesized and their space structure was elucidated by X-ray analysis. Conclusion: New effective method for synthesis of isoindoles condensed with various heterocycles was proposed. The method is based on the IMDAF reaction and provided a broad diversity of target molecules with controlled stereochemistry.

When azo coupling of aryldiazonium salts with indoles was carried out in aprotic nonpolar solvent on air, a pseudo-three-component reaction has been discovered. Azo coupling is followed by a nucleophilic addition of a second indole unit to the indolium intermediate; aromatization and oxidation are achieved under air.

A new class of trifluoromethyl building blocks─2-trifluoromethyl allyl chlorides─have been obtained through a photoredox-catalyzed chlorotrifluoromethylation of aryl allenes. The reaction proceeded in a regio- and stereoselective manner. A trifluoromethylated analog of the flunarizine drug was synthesized.

Tetrahydroisoquinolines underwent tandem piperidine ring enlargement in the presence of activated alkynes in acetonitrile or methanol, producing tetrahydrobenzo[d]azocines in high yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Acylation of 4furyl24Raminobut1enes and 4R4furfurylaminobut1enes with maleic anhydride, acryloyl chloride or allylhalides provided 3aza10oxatricyclo5.2.1.01,5decenes. The tricycles are formed viaan initial amide formation followed by a stereoselective exoIMDAF Intramolecular DielsAlder of Furan. In case of competing cycloaddition for compounds possessing two furan or two dienophilic moieties the most substituted fivemembered cycle is preferably annulated. Refluxing of 4R4furfurylaminobut1enes in acetic anhydride led to exo3aza11oxatricyclo6.2.1.01,6undecenes with the pseudoequatorial substituent R4. Treatment of 3aza10oxatricyclo5.2.1.01,5decenes with PPA at 90−110°C promoted cyclic ether opening, aromatization and intramolecular cyclization reactions sequence to give the corresponding tetracyclic compounds — tetrahydroisoindolo2,1aquinolines and tetrahydroisoindolo2,1b2benzazepines in good yields. Unusual products of ipsosubstitution in aromatic ring were obtained on cyclization of NpRsubstituted 2allyl4oxo3aza10oxatricyclo5.2.1.01,5dec8enes.

The published data on the intramolecular Diels–Alder reaction in compounds of the 2-alkenylfuran series are generalised. The methods and conditions for the preparation of tricyclic systems are considered. The effects of the substituents in the furan and the unsaturated fragments on the cycloaddition are discussed. The application of this reaction to the synthesis of alkaloids and terpenoids is exemplified. The bibliography includes 168 references.

The reaction of 10carboxamido tetrahydrobenzob1,6naphthyridines 13with activated terminal alkynes in DMFmethanol resulted with the formation of hexahydrobenzobpyrido3,4,5de1,6naphthyridines 710 representatives of a new heterocyclic system.

A series of 4,5,6,7‐tetrahydro‐1H‐pyrrolo[3,2‐c]pyridines (THPPs), mostly C(2)‐substituted derivatives, and some 2, 3, 4, 5‐tetrahydro‐1H‐pyrido[4, 3‐b]indoles (THPIs) were synthesized and tested in‐vitro for their ability to inhibit aggregation of human platelet‐rich plasma (PRP) induced by adenosine 5′‐diphosphate (ADP) and adrenaline (epinephrine). 5‐Benzyl THPP (3), 2‐(benzylamino)methyl THPP (5f) and 2‐ethyl THPI (6) moderately and dose‐dependently inhibited platelet aggregation induced by adrenaline and, to a lesser extent, by ADP. These compounds inhibited the second phase of the PRP aggregation triggered by adrenaline, which largely depends upon thromboxane A2production and ADP release. In the adrenaline‐stimulated aggregation, the THPI derivative 6 was found to be nearly equipotent with aspirin, their IC50 values (concentration effecting 50% inhibition of aggregation) being 90 and 60 μM, respectively. A relation between activity and calculated octanol‐water partition coefficient suggested that a log P value around 2.5 should be the optimal lipophilicity value for the activity of THPP‐containing compounds.

A series of 4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridines (THPPs), mostly C(2)-substituted derivatives, and some 2, 3, 4, 5-tetrahydro-1H-pyrido[4, 3-b]indoles (THPIs) were synthesized and tested in-vitro for their ability to inhibit aggregation of human platelet-rich plasma (PRP) induced by adenosine 5′-diphosphate (ADP) and adrenaline (epinephrine). 5-Benzyl THPP (3), 2-(benzylamino)methyl THPP (5f) and 2-ethyl THPI (6) moderately and dose-dependently inhibited platelet aggregation induced by adrenaline and, to a lesser extent, by ADP. These compounds inhibited the second phase of the PRP aggregation triggered by adrenaline, which largely depends upon thromboxane A2production and ADP release. In the adrenaline-stimulated aggregation, the THPI derivative 6 was found to be nearly equipotent with aspirin, their IC50 values (concentration effecting 50% inhibition of aggregation) being 90 and 60 μM, respectively. A relation between activity and calculated octanol-water partition coefficient suggested that a log P value around 2.5 should be the optimal lipophilicity value for the activity of THPP-containing compounds.

The reaction between allylmagnesium bromide and imines 5a-l leads to the corresponding 4-substituted 4-N-benzylaminobut-1-enes 6a-l, which were oxidized in a regioselective manner to the alkenylnitrones 7a-l. The intramolecular 1,3-dipolar cycloaddition of these nitrones gave 2-spiroannulated or 2-substituted 6-exo-phenyl-1-aza-7-oxabicyclo[2.2.1]heptanes 8a-j. Reductive cleavage of the N-O bond of the obtained bicycles afforded the diverse substituted 4-hydroxypiperidines 9a-h in good yields. This stereoselective approach allowed the preparation of all-cis-4-hydroxy-6-phenyl-2-nonylpiperidine (9i), a close analogue of dendrobatid frog alkaloid 241D.

4-Methyl-substituted tetrahydropyrrolo[3,2-c]pyridines reacted with acetic anhydride to produce substituted 3-vinylpyrroles in low to moderate yields.

The title compounds were synthesised by the intramolecular [4+2]-cycloaddition of 1-N-furfurylamino-1-allylcyclanes in the presence of acetic anhydride.

The oxidation of 1,2,4,5-tetrahydrospiro[3H-2-benzazepine-3,1'-cycloalkanes] by KMnO₄ under phase-transfer conditions gives the corresponding substituted cyclic imines in high yields.

N‐Alkylation of isoquinoline derivatives with alkyl halides affords intermediate iminium salts, which undergo unexpected spontaneous intramolecular Diels—Alder reaction to produce cycloadducts with the basic structural core of the title alkaloids.

The intramolecular furan Diels—Alder reaction (IMDAF) of azomethines, prepared from furfurals and amino alcohols or thiols, with dienophiles (III) and (IX) affords the title skeletons in low to moderate yields.

A series of novel epoxypyrido[2,1‐a]isoindole derivatives is prepared by highly regio‐ and stereoselective Diels—Alder reactions.

A simple one‐pot protocol allows the synthesis of the title compounds via a cascade reaction of immonium salts (I) and α‐hydroxyaromatic aldehydes.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.