Unusual reactions of ?-nitro-?-dimethylaminoacrolein

Krasnaya, Zh. A.; Stytsenko, T. S.; Bogdanov, V. S.; Даева, Е. Д.

doi:10.1007/bf00950150

Cited by 4 publications

(6 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…23 They possess interesting solvato-, thermo-, and photochromic properties due to the potential of valence isomerization to 2H-pyrans 8a-h. 24 Using MAA as a prototypical stabilized enolate we have prepared a range of pyridines and pyridine Noxides, including 5-chloro, 5-aryl, and 5-trifluoromethyl substitution, which arise via the intermediacy of the dienone 7a-h. During our studies to further expand the scope of this methodology we investigated the reaction of MAA and the nitrovinamidinium salt 3 25 at 45 °C in THF. To our surprise, none of the expected pyridine was observed, and two aromatic compounds, aniline 4 26 and phenol 5, 27 were isolated in 65% and 10% yield, respectively, prior to the addition of ammonia (∼4:1 in the crude reaction mixture). The identity of the aniline 4 was confirmed by comparison with an authentic sample prepared from dimethylamine and 2-chloro-5-nitro-benzoate 28 and was further supported by X-ray crystallographic analysis of analogue 21d.…”

Section: Resultsmentioning

confidence: 79%

“…During our studies to further expand the scope of this methodology we investigated the reaction of MAA and the nitrovinamidinium salt 3 at 45 °C in THF. To our surprise, none of the expected pyridine was observed, and two aromatic compounds, aniline 4 and phenol 5 , were isolated in 65% and 10% yield, respectively, prior to the addition of ammonia (∼4:1 in the crude reaction mixture). The identity of the aniline 4 was confirmed by comparison with an authentic sample prepared from dimethylamine and 2-chloro-5-nitro-benzoate and was further supported by X-ray crystallographic analysis of analogue 21d .…”

Section: Resultsmentioning

confidence: 80%

See 1 more Smart Citation

Demonstrating the Synergy of Synthetic, Mechanistic, and Computational Studies in a Regioselective Aniline Synthesis

Davies

Marcoux²,

Kuethe³

et al. 2004

J. Org. Chem.

View full text Add to dashboard Cite

Tri- and tetrasubstituted anilines are formed in good to excellent yields by the addition of ketones to vinamidinium salts (up to 98%). The reaction proceeds via the formation of dienone intermediates, which react to form an enamine with the liberated amine. In the case of a nitro, or dimethylaminomethylene substituent, the enamines undergo a facile electrocyclic ring closure to form a cyclohexadiene, which goes on to form anilines with a high degree of selectivity (up to 50:1) with a minor competing pathway proceeding via the enol providing phenols. Competition experiments using isotopic substitution reveal that the rate determining step en route to dienone is enol/enolate addition to the vinamidinium salt, which is characterized by an inverse secondary isotope effect (k(H/D) 0.7-0.9). Computational studies have been used to provide a framework for understanding the reaction pathway. The original proposal for a [1,5]-H shift was ruled out on the basis of the calculations, which did not locate a thermally accessible transition state. The minimum energy conformation of the enamine is such that a facile electrocyclic ring closure is ensured, which is corroborated by the experimental studies. A framework for understanding the reaction pathway is presented.

show abstract

Section: Resultsmentioning

confidence: 79%

Section: Resultsmentioning

confidence: 80%

Demonstrating the Synergy of Synthetic, Mechanistic, and Computational Studies in a Regioselective Aniline Synthesis

Davies

Marcoux²,

Kuethe³

et al. 2004

J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…Vinamidinium salts react with methylacetoacetate to form dienones. In the case of protio-, 1 phenyl-, 2 chloro-, 3 fluoro-, 4 and cyano-substituted 5 dienones they do not undergo subsequent spontaneous downstream chemistry. However, we have demonstrated that ring closure to provide aromatic products occurs in the case of nitro-, phenylsulfonyl-, and dimethylaminomethylene substitution.…”

Section: Introductionmentioning

confidence: 98%

“…Vinamidinium salts react with methylacetoacetate to form dienones. In the case of protio-, phenyl-, chloro-, fluoro-, and cyano-substituted dienones they do not undergo subsequent spontaneous downstream chemistry. However, we have demonstrated that ring closure to provide aromatic products occurs in the case of nitro-, phenylsulfonyl-, and dimethylaminomethylene substitution. , The major reaction pathway has been formalized as (1) enamine or enol formation, (2) electrocyclization, and (3) elimination of dimethylamine to provide the aromatic product (Scheme ) .…”

Section: Introductionmentioning

confidence: 99%

Computational Studies on the Electrocyclizations of 1-Amino-1,3,5-hexatrienes

2004

View full text Add to dashboard Cite

Electrocyclizations of 1,3,5-hexatrienes containing up to four electron-donating and/or electron withdrawing substituents have been studied computationally using the hybrid density functional, B3LYP. Electron donating substituents at positions C-1 and C-5 decrease activation barriers by 0.3 to 2.3 kcal/mol. Introducing of an electron-withdrawing group, CO(2)Me, at C-4 further decreases the activation energy by 7 kcal/mol. Electron-withdrawing groups (NO(2), SO(2)Ph and C=N(+)Me(2)) at C-2 have a profound effect of 17-25 kcal/mol on the activation energy.

show abstract

“…Compounds of type 3 are also accessible from ketene aminals and the DMF/DMS-complex, 5 N,N′-peralkylated acetamidinium salts and Brederecks reagent, 6 and amide acetals, 7 respectively. The reaction of secondary amines or silylated secondary amines with vinylogous Viehe salts, 8 vinylogous chloroformamidinium salts, 9 or N,N-dimethyl-2-chloro-3dimethylaminopropeniminium chloride, 10 or 1-dimethylamino-3-methylthio-2,4,4,-trichlorocyclobutenylium fluorosulfate 11 also affords vinylogous guanidinium salts. Treatment of orthoamides of alkynecarboxylic acids with acetic acid 3a or even weaker acidic compounds such as chloroform 4b or 2-methyl-1,3,4-thiadiazolium salts 12 gives rise to the formation of compounds of type 3.…”

mentioning

confidence: 99%