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Shklyaev, Yu. V.; Nifontov, Yu. V.; Shashkov, Alexander S.; Фирганг, С. И.

doi:10.1023/a:1022183318380

Cited by 4 publications

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“…As we showed previously [6], three-component condensation of p-methoxytoluene with isobutyraldehyde and nitriles is accompanied by additional alkylation. However, in the reaction of p-methoxytoluene with isobutyraldehyde and 3-oxo-2-phenylbutanenitrile, apart from the expected product, 3,3,9-trimethyl-8-(2-methoxy-5-methylphenyl)-1-(2-oxo-1-phenylpropyl)-2-azaspiro[4.5]deca-1,7-dien-6-one (III, 17%)), we succeeded in isolating 2% of 8-acetyl-1,6,6-trimethyl-3,4,5,6,7,12b-hexahydrodibenzo[d,f]indol-4-one (IV) formed as a result of intramolecular alkylation of the aromatic ring (Scheme 3).…”

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Three-component condensation of o- and p-methoxytoluenes with isobutyraldehyde and α-substituted benzyl cyanides. Synthetic approach to analogs of natural alkaloids

2010

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Three-component condensation of o(p)-methoxytoluene with isobutyraldehyde and α-substiituted benzyl cyanides gave 8-acetyl-3,6,6-trimethyl-5,6,7,12b-tetrahydrodibenzo[d,f]indol-2(1H)-one or 8-acetyl-1,6,6-trimethyl-3,4,5,6,7,12b-hexahydrodibenzo[d,f]indol-3-one. Analogous reaction of p-methoxytoluene with isobutyraldehyde and 1-phenylcyclopentane-1-carbonitrile afforded 1′,6′,6′-trimethyl-3′,4′,5′,6′,7′,12b′-hexahy-We reported previously that three-component condensation of anisole with isobutyraldehyde and phenylacetoacetonitrile yields 3,3-dimethyl-1-(2-oxo-1-phenylpropylidene)-2-azaspiro[4.5]deca-6,9-dien-8-one [1]. Analogous spiro heterocycle A was obtained by reaction of o-methoxytoluene with isobutyraldehyde and methyl thiocyanate [2]. addition, we isolated minor compound II with the same molecular weight but different 1 H NMR spectrum (Scheme 1). The 1 H NMR spectrum of I contained a singlet at δ 1.41 ppm from protons in the methyl group on C 7 , a singlet at δ 6.64 ppm from 6-H, and a doublet at δ 5.58 ppm (J = 9.9 Hz) from 10-H. The 9-H signal was overlapped by aromatic multiplet at δ 6.91-7.03 ppm. In the 1 H NMR spectrum of II we observed only one singlet at δ 6.43 ppm from the 4-H proton, and three protons gave rise to an ABM pattern in the aliphatic region. Signals from two carbon atoms in the dienone fragment were displaced to aliphatic region of the 13 C NMR spectrum. Methylene protons on C 5 resonated as an AB spin system at δ 1.90 ppm (J = 12.8 Hz), and those on C 1 also appeared as an AB pattern centered at δ 2.74 ppm (J = 16.5 Hz). These findings, in combination with the data of elemental analysis, allowed us to assign the structures of 3,3,7-trimethyl-1-(2-oxo-1-phenylpropyl)-2-azaspiro[4.5]-

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confidence: 72%

Three-component condensation of o- and p-methoxytoluenes with isobutyraldehyde and α-substituted benzyl cyanides. Synthetic approach to analogs of natural alkaloids

2010

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“…The synthesis of spiro-fused pyrrolidine 56 (Scheme 22) and its pharmacological activity were reported in [60][61][62][63][64][65]. Isobutyraldehyde 9c was a convenient synthon in consecutive Baeyer and Ritter reactions, and the products showed moderate analgesic activity [61].…”

Section: Derivatives Of Pyrrole and Its Partly Hydrogenated Analogsmentioning

confidence: 99%

Aliphatic aldehydes in the synthesis of carbo- and heterocycles. Part I. Synthesis of three-, four-, and five-membered rings

Dyachenko

Karpov

2010

Russ J Org Chem

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“…We previously proposed a procedure for the synthesis of 2-azaspiro [4.5]deca-6,9-dien-8-ones and 2-azaspiro [4.5]deca-1,6,9-trien-8-ones on the basis of three-component condensation of anisole [30] or substituted anisoles [31][32][33][34] with an α-branched aldehyde and a nitrile under acid catalysis. In continuation of these studies in the present work we examined threecomponent condensation of isobutyraldehyde with phenols and nitriles, catalyzed by concentrated sulfuric acid.…”

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Synthesis of 1-substituted 2-azaspiro[4.5]deca-6,9-dien-8-ones and 2-azaspiro[4.5]deca-1,6,9-trien-8-ones by condensation of 2,6-dimethylphenol with isobutyraldehyde and nitriles

et al. 2012

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1-Substituted 3, 3,7,9-tetramethyl-2-azaspiro[4.5]deca-6,9-dien-8-ones and 3,3,7,9-tetramethyl-2-azaspiro[4.5]deca-1,6,9-trien-8-ones were synthesized by three-component condensation of 2,6-dimethylphenol with isobutyraldehyde and nitriles in concentrated sulfuric acid.Compounds having a 2-azaspiro[4.5]decane skeleton rarely occur in nature. Examples of such structures are annosqualine isolated from the Stems of Annona squamosa [1], spirostaphylotrichins produced by Staphylotrichum coccosporum [2][3][4], triticones (spirocyclic lactams from the fungal plant pathogen Drechslera tritici-repentis [5]), and spiro-arogenate (a spiro-γ-lactam produced by Neurospora crassa from prephenic acid [6,7]). Some 2-azaspiro[4.5]decanes attract certain interest from the viewpoints of medicinal and synthetic organic chemistry. Some synthetic analogs of natural 2-azaspirane derivatives showed high immunosupressive activity [8]. Kazmierski et al. [9] proposed novel HIV-1 protease inhibitors on the basis of a spirocyclic pyrrolidone. It was also found that 2-azaspiranes are formed as intermediate products in the Bischler-Napieralski [10,11] or Ritter [12] syntheses of isoquinolines and phenanthridines. Several synthetic approaches to 2-azaspiro[4.5]-decane derivatives have been reported. Some procedures imply building of 2-azaspiro[4.5]decane skeleton from cyclohexanone or cyclohexene fragments. 2-Azaspiranes can be synthesized according to BuchwaldHartwig via intramolecular cyclization of the corresponding cyclohexanone derivatives [13] and by radical cyclization of N,N-diallyl-2-oxocyclohexanecarboxamides in the presence of Mn(OAc) 3 [14] or of 2-bromo-substituted diene amides, e.g., N-benzyl-2-bromo-N-[1-(cyclohex-1-en-1-yl)vinyl]propanamide, in the presence of CuBr-(C 5 H 5 N) 3 N [15]. A group of methods for the preparation of 2-azaspirane systems is based on dearomatization of arenes with simultaneous construction of pyrrolidinone fragment. Acid-catalyzed intramolecular ipso-cyclization of electron-rich aromatic diazoacetamides [16] or thionium ions generated by reaction of N-benzylglyoxamides with thiols [17] leads to the formation of spirocyclic lactams. 2-Azaspiranes can also be obtained by oxidative radical ipsocyclization of N- [p-methoxy(hydroxy)benzyl]acetamides [18] and substituted N-benzyltrichloroacetamides [19]. developed a procedure for the synthesis of 2-azaspiranes via aromatic nucleophilic substitution in the presence of (η 6 -arene)RuCp + complexes. Another possible way to 2-azaspiranes is based on the reaction of tricarbonyl (η 5 -1-alkyl-4-methoxycyclohexadienylium)iron with difunctional nucleophiles [25]. Intramolecular ene-type [6 + 2]-cyclization of Fe(CO) 3 -(cyclohexa-1,3-diene) complexes having a pendant double bond was reported to afford spirocyclic systems [26][27][28]. 2-Azaspiro[4.5]-deca-6,9-diene-3,8-diones were synthesized by tandem Ugi reaction and intramolecular Michael 5-exoaddition [29].

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Cited by 4 publications

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Three-component condensation of o- and p-methoxytoluenes with isobutyraldehyde and α-substituted benzyl cyanides. Synthetic approach to analogs of natural alkaloids

Three-component condensation of o- and p-methoxytoluenes with isobutyraldehyde and α-substituted benzyl cyanides. Synthetic approach to analogs of natural alkaloids

Aliphatic aldehydes in the synthesis of carbo- and heterocycles. Part I. Synthesis of three-, four-, and five-membered rings

Synthesis of 1-substituted 2-azaspiro[4.5]deca-6,9-dien-8-ones and 2-azaspiro[4.5]deca-1,6,9-trien-8-ones by condensation of 2,6-dimethylphenol with isobutyraldehyde and nitriles

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