Synthesis of 2,5-bis(N,N-dialkylamino)thiophenes or 1-alkyl-2-N,N-dialkylamino-5-methylthiopyrroles from propargylic amines and isothiocyanates

Тарасова, О. А.; Nedolya, N. А.; Vvedensky, Vladimir Y.; Brandsma, L.; Трофимов, Б. А.

doi:10.1016/s0040-4039(97)01680-8

Cited by 57 publications

(28 citation statements)

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“…[9] This surprising result may be explained by assuming an equilibrium between the anions 4 and 7, which may result from two ring-closure modes in the resonance hybrid 3 o 3a. (Scheme 2).…”

Section: Syntheses Involving Alkynyllithiums and Isothiocyanatesmentioning

confidence: 99%

Unsaturated Carbanions, Heterocumulenes and Thiocarbonyl Compounds − New Routes to Heterocycles

Brandsma

2001

Eur. J. Org. Chem.

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“…[9] This surprising result may be explained by assuming an equilibrium between the anions 4 and 7, which may result from two ring-closure modes in the resonance hybrid 3 o 3a. (Scheme 2).…”

Section: Syntheses Involving Alkynyllithiums and Isothiocyanatesmentioning

confidence: 99%

Unsaturated Carbanions, Heterocumulenes and Thiocarbonyl Compounds − New Routes to Heterocycles

Brandsma

2001

Eur. J. Org. Chem.

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“…2,3 Part of our investigations is dealing with base-catalyzed cyclizations. [4][5][6] For example, reaction of lithiated allene 1 (R 1 = t-Bu) with isothiocyanates R 2 N=C=S, followed by successive addition of t-BuOH and t-BuOK in DMSO and final methylation or reaction with water gave 5-(tert-butyl)-substituted 2-aminothiophenes 2 or 3, respectively, in good yields (Scheme 1). 5 Intermediates 4 could also be generated by treatment of the adducts from lithiated acetylenes R 1 CH 2 C≡CLi and R 2 N=C=S with t-BuOH, t-BuOK and DMSO.…”

Section: Introductionmentioning

confidence: 99%

“…5 Intermediates 4 could also be generated by treatment of the adducts from lithiated acetylenes R 1 CH 2 C≡CLi and R 2 N=C=S with t-BuOH, t-BuOK and DMSO. 5,6 Scheme 1…”

Section: Introductionmentioning

confidence: 99%

N-[5,5-dimethyl-2(5H)-thiophenyliden]amines and N-(1-thiaspiro[4.5]dec-3-en-2-yliden)amines: Synthesis and isomerism

Nedolya¹,

Brandsma²,

Schlyakhtina³

et al. 2001

Arkivoc

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A number of N- [5,5-dimethyl-2(5H)-thiophenyliden]amines and N- (1-thiaspiro[4.5]dec-3-en-2-yliden)amines, existing exclusively in one isomeric form, have been obtained in good to excellent yields by reaction of lithiated 1,1-disubstituted 1,2-dienes with isothiocyanates followed by treatment with t-BuOH and t-BuOK in DMSO. Investigation of the isomeric structures using 1H, 13C, 15N, 2D NOESY NMR spectroscopy and quantum-chemical calculation (ab initio HF/6-31G*) of the total energies of the fully optimized geometries indicated that for both N- [5,5-dimethyl-2(5H)-thiophenyliden]methanamine and N-(1-thiaspiro[4.5]dec-3-en-2-yliden)methanamine the Z-isomers are more stable, the energy differences with respect to E-isomers being 3.37-3.87 kcal/mol. It was established that the chair conformer with axial orientation of sulfur of (Z)-N-(1-thiaspiro[4.5]dec-3-en-2-yliden)methanamine the has the lowest energy of all possible conformers.

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“…Pyrroles can be found in a large range of natural products [9] and bioactive molecules [10][11][12][13][14], including the blockbuster drug Atorvastatin calcium [10], as well as important anti-inflammatory agents [11], antitumor agents [12], and immunosuppressants [13]. Accordingly, substantial attention has been paid to develop efficient methods for the synthesis of pyrroles [1][2][3][4][5][6][7][8][15][16][17].One of the most common approaches to pyrrole synthesis is the PaalKnorr reaction in which 1,4-dicarbonyl compounds are converted to pyrroles via acid-mediated dehydrative cyclization in the presence of a primary amine [18][19][20][21][22][23][24][25][26][27][28][29][30]. In this reaction, the 1,4-dicarbonyl compound provides the four carbons of the pyrrole with their substituents, whereas the amine provides the nitrogen with its substituent.…”

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confidence: 99%

Synthesis of new N-alkyl(aryl)-2,4-diaryl-1H-pyrrol-3-ols via aldol Paal–Knorr reactions

Eftekhari‐Sis

Akbari

Amirabedi

2011

Chem Heterocycl Comp

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New N-alkyl(aryl)-2,4-diaryl-1H-pyrrol-3-ol derivatives have been synthesized in moderate to good yields in a novel and efficient process by aldol reaction of 1-(4-methoxyphenyl)propan-2-ones with phenylglyoxal in the presence of DABCO in water, followed by PaalKnorr reaction with amines in the presence of a catalytic amount of p-TSA in toluene at reflux.Pyrroles are important heterocycles widely used in material science (for recent work, see [1]) and found in naturally occurring and biologically important molecules [2][3][4][5][6][7][8]. Pyrroles can be found in a large range of natural products [9] and bioactive molecules [10][11][12][13][14], including the blockbuster drug Atorvastatin calcium [10], as well as important anti-inflammatory agents [11], antitumor agents [12], and immunosuppressants [13]. Accordingly, substantial attention has been paid to develop efficient methods for the synthesis of pyrroles [1][2][3][4][5][6][7][8][15][16][17].One of the most common approaches to pyrrole synthesis is the PaalKnorr reaction in which 1,4-dicarbonyl compounds are converted to pyrroles via acid-mediated dehydrative cyclization in the presence of a primary amine [18][19][20][21][22][23][24][25][26][27][28][29][30]. In this reaction, the 1,4-dicarbonyl compound provides the four carbons of the pyrrole with their substituents, whereas the amine provides the nitrogen with its substituent. The main limitations to intensive use of this reaction are the harsh reaction conditions required for cyclization (use of boiling acetic acid for extended times) and the low availability of nonsymmetrically substituted 1,4-dicarbonyl compounds. The classical approach to this class of products is the condensation of enolates with phenacyl bromides [31], thus limiting the method to pyrroles with aryl substituents. Alternative approaches need several reaction steps with chromatographic separations to obtain the intermediates for cyclization. Therefore, mild reaction conditions that can overcome some of the shortcomings of the previous methods are necessary.In this paper, we describe a simple method for synthesis of new N-alkyl(aryl)-2,4-diaryl-1H-pyrrol-3-ol derivatives via aldol reaction of 1-(4-methoxyphenyl)propan-2-one with phenylglyoxal in the presence of a catalytic amount of 1,4-diazabicyclo[2.2.2]octane (DABCO) in water at room temperature, followed by

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Synthesis of 2,5-bis(N,N-dialkylamino)thiophenes or 1-alkyl-2-N,N-dialkylamino-5-methylthiopyrroles from propargylic amines and isothiocyanates

Cited by 57 publications

References 1 publication

Unsaturated Carbanions, Heterocumulenes and Thiocarbonyl Compounds − New Routes to Heterocycles

Unsaturated Carbanions, Heterocumulenes and Thiocarbonyl Compounds − New Routes to Heterocycles

N-[5,5-dimethyl-2(5H)-thiophenyliden]amines and N-(1-thiaspiro[4.5]dec-3-en-2-yliden)amines: Synthesis and isomerism

Synthesis of new N-alkyl(aryl)-2,4-diaryl-1H-pyrrol-3-ols via aldol Paal–Knorr reactions

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