Synthesis of spiro[furan-3,3′-indolin]-2′-ones by PET-catalyzed [3+2] reactions of spiro[indoline-3,2′-oxiran]-2-ones with electron-rich olefins

An efficient procedure for the synthesis of spiro[furan-3,3′-indolin]-2-ones and dispiro[cycloalkane-1,2′-furan-3′,3″-indolin]-2″-ones has been achieved in high yields and stereoselectivity by photoinduced electron transfer-catalyzed [3+2] reactions of substituted spiro[indoline-3,2′-oxiran]-2-ones with olefins. The reactions proceed by ring opening of spiro[indoline-3,2′-oxiran]-2-ones via C_β–O bond cleavage and subsequent cycloaddition with olefins by using 2,4,6-triphenylpyrylium tetarfluoroborate (TPT) as a sensitizer.     

Synthesis of spiro[isoquinoline-4,4′-pyran]-3-imines

A method has been developed for the synthesis of 4-[2-(bromomethyl)phenyl] tetrahydro-2H-4-pyrancarbonitrile and a study was carried out on the reaction of this compound with primary amines, which, depending on the conditions, leads to either 4-[2-(R-aminomethyl)phenyl]tetrahydro-2H-4-pyrancarbonitriles or hydrobromides of 2-R-aryl-2,3,2,3,5,6-hexahydrospiro[isoquinoline-4(1H),4-pyran]-3-imines.Taras Shevchenko Kiev University, 252017 Kiev, Ukraine; e-mail: vkysil@mail.univ.kiev.ua. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1035–1041, August, 2000.     

Substituted and fused spiro[benzo-2-azepine-3,1′-cyclohexanes]

5-Methyl-4,5-dihydro-3H-spiro[benzo-2-azepine-3,1-cyclohexane] N-oxide was rear- ranged into 5-methyl-1-oxo-1,2,4,5-tetrahydro-3H-spiro[benzo-2-azepine-3,1-cyclohexane]. The latter was used for the synthesis of spiro{triazolo[3,4-a]- and-tetrazolo[5,1-a]benzo-2- azepinecyclohexanes}.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1647–1651, August, 2004.     

A new rearrangement of spiro[indane-1,3′-thiophene] and spiro[naphthalene-1,3′-thiophene] derivatives accompanied by opening of the cycloalkane ring

Abstract  

The new thioamides 2-oxoindane-1-carbothioamides and 2-oxo-1,2,3,4-tetrahydronaphthalene-1-carbothioamides underwent conjugated addition to (E)-β-nitrostyrenes followed by cyclization to give products containing 5-hydroxyimino-2-aryliminothiophene rings spiro-annulated to the 2-indanone or 2-tetralone system. On treatment with hydrochloric acid in boiling methanol the compounds underwent a new rearrangement, involving transformation of the 2-aryliminothiophene ring to a pyrrole and an opening of the alicyclic ring in the proximity of the carbonyl group, affording 2-(1,3-diaryl-2-oxo-5-thioxopyrrol-4-yl)benzeneacetic or 2-(1,3-diaryl-2-oxo-5-thioxopyrrol-4-yl)benzenepropanoic acid methyl esters. The structures of two selected pyrrole derivatives were determined by X-ray crystal analyses. The thioamides derived from 2-indanone showed unexpected reactivity towards primary alcohols and underwent conversion to 2-hydroxy-1H-indene-3-thiocarboxylic acid O-esters.     

Catalyst-free glycerol-mediated green synthesis of 5′-thioxospiro[indoline-3,3′-[1,2,4]triazolidin]-2-ones/spiro[indoline-3,3′-[1,2,4]triazolidine]-2,5′-diones

The development of new catalyst-free green and efficient protocol to access 5′-thioxospiro[indoline-3,3′-[1,2,4]triazolidin]-2-ones/spiro[indoline-3,3′-[1,2,4]triazolidine]-2,5′-diones, potential privileged scaffolds for drug discovery, is disclosed. Key feature of this methodology is the dual use of glycerol—a recyclable, bioorganic compound, as a solvent cum promoter. Other highlights include use of inexpensive reagents, mild reaction conditions, operational simplicity, short reaction time, no need for chromatographic purification, and high yields.     

Recyclization of spiro[3a-Hydroxypiperidin-4,2′-oxiranes] in basic medium

It is shown that heating spiro[3a-hydroxypiperidin-4,2-oxiranes] in aqueous base gives rearrangement into derivatives of 3,4-epoxypiperidines. The structures of the latter were confirmed by spectral data and by chemical informations.Belorussian State Technological University, Minsk 220030. Translated from Khimiya Geterotsiklicheskikh Soedineii, No. 9, pp. 1213–1215, September, 1994. Original article submitted July 29, 1994.     

Synthesis of spiro(benzo[h]quinazoline-5,1′-cyclohexane) derivatives

3-p-Methoxyphenyl-4-oxo-2-mercapto-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-4,1 -cyclohexane) wassynthesized by the reaction of 4-amino-3-ethoxycarbonvl-1, 2-dihydrospiro(naphthalene-2,1 '-cyclohexane) (1) with p-methoxyphenvl isothiocyanate without separation of the thioureido derivative. Amino ester 1 is transformed byacetamide and formamideinto 2-methyl-4-oxo-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-5,1 -cyclohexane) and 4-oxo-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexane (11), respectively. Alkylation of quinazoline 11 with methyl iodide results in formation of 3-methyl-4-oxo-3, 4, 5, 6-tetrahydro-spiro (benzo[h]quinazoline-5,1 -cyclohexane). Amino ester 1 reacts with caprolactam with formation of 2, 3 pentamethylene-4-oxo-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexane). 4-Ethoxymethyleneamino-3-ethoxy-carbonyl-1,2-dihydrospiro(naphthalene-2,1-cyclohexane) was synthesized by the reaction of amino ester 1 with o-formic ester, and was converted into 3-amino-4-oxo-3, 4,5, 6-tetrahydro-spiro(benzo[h]quinazoline-5,1-cyclohexane) (VIII) by hydrazine hydrate. Aminoquinazoline VIII is acylated by acid chlorides with formation of 3-acylamino-4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexanes) and forms 3-benzyl-ideneamino-4-oxo-3,4,5,6-teirahydrospiro(benzo[h]quinazoline-5,1-cyclohexane) with benzaldehyde.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 530–533, April, 1996     

Syntheses of spiro[indazole-3,3′-indolin]-2′-ones and spiro[indazole-3,3′-indolin]-2′-imines via 1,3-dipolar cycloadditions of arynes and studies on their isomerization reactions

A 1,3-dipolar cycloaddition reaction of arynes with 3-diazoindolin-2-ones under mild conditions in excellent yields has been developed, which allows facile access to a library of labile spiro[indazole-3,3′-indolin]-2′-ones. Spiro[indazole-3,3′-indolin]-2′-imines could be obtained as well following the same protocol. The isomerization reaction of spiro[indazole-3,3′-indolin]-2′-ones under thermal or acidic conditions has been efficiently achieved to afford a wide range of indazolo-[2,3-c]quinazolin-6(5H)-ones and the one-pot synthesis of indazolo-[2,3-c]quinazolin-6(5H)-ones from arynes and 3-diazoindolin-2-ones is also described. Whereas, spiro[indazole-3,3′-indolin]-2′-imines could not undergo the same rearrangement.     

Efficient multicomponent synthesis of spiro[indoline-3,4′-thiopyran]-2-ones

Synthesis of new thiopyran fused spirooxindoles (spiro[indoline-3,4′-thiopyran]-2-ones) were achieved by a multicomponent reaction of N-methyl isatin, malononitrile/ethyl cyanoacetate, and β-oxodithioester using N,N′-dimethylaminopyridine as the catalyst.     

Cu(II)-β-cyclodextrin-catalyzed synthesis of spiro[indoline-3,4′-pyrano[3,2-c]chromene]-3′-carbonitrile derivatives

Cu(II)-β-cyclodextrin-catalyzed synthesis of spiro[indoline-3,4′-pyrano[3,2-c]chromene]-3′-carbonitriles through the reaction of isatin derivatives, 4-hydroxycoumarin, and malononitrile in ethanol at room temperature.     

Diethyl oxalacetate sodium salt as a reagent to obtain functionalized spiro[indoline-3,4′-pyrano[2,3-c]pyrazoles]

An efficient one-pot procedure for the synthesis of ethyl 6′-amino-5′-cyano-2-oxo-2′H-spiro[indoline-3,4′-pyrano[2,3-c]pyrazole]-3′-carboxylates in moderate to high yields is described.     

Titanium-catalyzed cyclocodimerization of cyclohepta-1,3,5-triene with spiro[cyclopropane-1,7′-norborna-2,5-diene]

Russian Chemical Bulletin - Titanium complexes-catalyzed codimerization of cyclohepta-1,3,5-triene with spiro[cyclopropane-1,7′-norborna-2,5-diene] affords...     

Multi-component synthesis of spiro[diindeno[1,2-b:2′,1′-e]pyridine-11,3′-indoline]-triones using zinc terephthalate metal-organic frameworks

The present article describes an efficient one-pot method for the preparation of spiro[diindeno[1,2-b:2′,1′-e]pyridine-11,3′-indoline]-trione derivatives from a three-component condensation reaction of 1,3-indandione, aromatic amines and isatins in the presence of a zinc terephthalate metal-organic framework Zn (BDC) MOF as the catalyst under solvent-free conditions. High yields, short reaction times, simple workup and environmentally benign procedure are advantages of this protocol. The Zn (BDC) MOF catalyst can be recovered and reused several times without loss of activity. The catalyst was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infra red, X-ray powder diffraction and thermal gravimetric analysis.     

Synthesis of spiro[pyrrole-2,5′-thiazoles] by heterocyclization of pyrrolobenzoxazinetriones with salicylaldehyde thiosemicarbazone

Russian Journal of Organic Chemistry - 3-Aroylpyrrolo[1,2-c][4,1]benzoxazine-1,2,4-triones reacted with salicylaldehyde thiosemicarbazone to give...     

Synthesis of homochiral spiro[4.4] nonane-1,6-diols

Homochiral cis,cis-; cis,trans- and trans,trans-spiro[4.4]nonane-1,6-diols were prepared via diastereoselective reduction of enantiomerically pure spiro[4.4]nonane-1,6-dione (1) with the corresponding reducing agents: lithium n-butyldiisobutylaluminium hydride for cis,cis-diol (2) with 88% yield; BH3·THF for cis, trans-diol (3) with 91% yield; LiAlH4 for trans,trans-diol (4) with 15% yield.     

Iodine catalyzed one-pot multi-component reaction to CF3-containing spiro[indene-2,3′-piperidine] derivatives

In the presence of a catalytic amount of molecular iodine (0.1 equiv.), the one-pot multi-component reaction of ethyl trifluoroacetoacetate 1, indan-1,3-dione 2, ammonium acetate 3 and aromatic aldehyde 4 mainly gave the ethyl-6′-hydroxy-1,3-dioxo-2′,4′-diaryl-6′-(trifluoromethyl)-1,3-dihydrospiro[indene-2,3′-piperidine]-5′-carboxylate derivatives 5, along with the minor product 2-trifluoromethyl-2,3,4,5-tetrahydro-1H-indeno[1,2-b]pyridine derivatives 6. A plausible reaction mechanism for the formation of 5, 6 was presented. The structures of compounds 5, 6 were fully confirmed by ¹H NMR, ¹⁹F NMR, MS, IR spectroscopies and elemental analysis or high resolution mass spectra (HRMS). Meanwhile, the representative 5a and 6h were further confirmed by XRD analysis.     

Synthesis of novel spiro[indole-3,3′-pyrrolidin]-2(1H)-ones

Diastereoselective [3+2] cycloaddition of azomethine ylide to 1,3-dimethyl-6-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-3a,9a-diphenyl-3,3a,9,9a-tetrahydroimidazo[4,5-e]thiazolo[3,2-b]-[1,2,4]triazine-2,7(1H,6H)-dione yields hitherto unknown 1,1′,3-trimethyl-3a,9a-diphenyl-3,3a,9,9a-tetrahydrodispiro(imidazo[4,5-e]thiazolo[3,2-b][1,2,4]triazine-6,3′-pyrrolidine-4′,3″-indole)-2,2″,7(1H,1″H)-triones.     

Domino Michael/aza-Wittig reaction in the diastereoselective construction of spiro[azepane-4,3′-oxindoles]

A convenient synthetic strategy for the diastereoselective assembly of spiro[azepane-4,3′-oxindoles] was developed via a Staudinger/Michael/aza-Wittig/reduction/N-deprotection reaction sequence starting from PMB-protected oxindole-substituted ethylazides. The key step of the method is a domino self-catalytic Michael/aza-Wittig reaction wherein the phosphazene moiety acts first as the catalyst and then as the reactant, resulting in the formation of a seven-membered N-heterocycle.     

Synthesis of Spiro[benzo[h]chromene-4,3′-indoles] and Spiro[benzo[f]chromene-1,3′-indoles]

Russian Journal of Organic Chemistry - New spiro heterocycles, spiro[benzo[h]chromene-4,3′-indoles] and spiro[benzo[f]chromene-1,3′-indoles], have been synthesized in 50–60% yield...     

Construction of indolenine-substituted spiro[pyrrolidine-2,3′-oxindoles] from 2-alkenylindolenines and isatin-derived azomethine ylides

An organic base-catalyzed 1,3-dipolar cycloaddition between 2-alkenylindolenines and azomethine ylides derived from isatins and benzylamines was successfully developed to assemble indolenine-substituted spiro [pyrrolidine-2,3′-oxindole] ring systems. Generally, good regioselectivities (up to 14:1 rr) and high yields (up to 91%) were obtained under mild conditions.