- Facile N-arylation of amidines and N,N-disubstituted amidines
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A metal-free method for the N-arylation of amidines and N,N-disubstituted amidines using o-silylaryl triflate under very mild reaction conditions is developed. The reactions are compatible with a variety of functional groups. Imines can also be N-arylated by this method. Preparation of substituted phenanthridines via a Pd catalyzed intramolecular cyclization of the iodine containing N-arylation product is demonstrated.
- Yao, Tuanli
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supporting information
p. 4623 - 4626
(2015/07/08)
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- Reductive monoalkylation of aromatic amines via amidine intermediates
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The convenience and efficiency of using amidines as intermediates in the reductive monoalkylation of aromatic amines has been demonstrated. This monoalkylation can be performed as either a two-step synthesis or a one-pot procedure. Several examples are presented which clearly demonstrate the utility of this new method for the methylation or ethylation of aromatic amines, including unprotected nucleosides.
- Zhang, Jianxing,Chang, Hui-Min,Kane, Robert R.
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p. 643 - 645
(2007/10/03)
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- 2-Aza-1,3-dienes with electron-releasing substituents at the 1,3 positions. Reagents for the construction of pyridine and pyrimidine derivatives
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New 2-aza-1,3-dienes bearing 1 and 3-donor substituents are prepared from N-thioacylacetamidines through deprotonation of N-ylidene acetamidinium iodides. The 2-aza-3-(dimethylamino)-1-(methylthio)-1-phenylbutadiene (3) is trapped in situ by the residual precursor salt acting as a heterodienophile to give the pyrimidine 5. Substituted 2-aza-1-(dimethylamino)-3-(methylthio) analogues react readily with a variety of electron-deficient dienophiles to yield pyridine or pyrimidine derivatives. The stereochemistry of the hetero Diels-Alder reaction in the cases of dimethyl fumarate and acrylonitrile has been assigned by X-ray diffraction analyses of the resulting tetrahydropyridines and corresponds to an exo selectivity. The number and nature of cycloadducts in the cases of dimethyl acetylenedicarboxylate and phenyl isothiocyanate depend on C-4 substitution. The results obtained from the C-4 unsubstituted azabutadiene 8 are explained by an allylic rearrangement involving the 1,3-migration of dimethylamino group in the primary [4+2] adduct.
- Morel, Georges,Marchand, Evelyne,Pradere, Jean-Paul,Toupet, Loic,Sinbandhit, Sourisak
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p. 10095 - 10112
(2007/10/03)
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- REACTION OF PHENYL AZIDE WITH N,N-DIMETHYL-AMINOMETHYLENEPHENYLPHOSPHINES
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Phenyl azide reacts with N,N-dimethylamino-P-phenylmethylenephosphines with cleavage of the phosphorus-carbon double bond and formation of the dimer of diiminophosphorane and amidines.
- Arbuzov, B. A.,Ionkin, A. S.,Ignat'eva, S. N.,Efremov, Yu. Ya.,Nekhoroshkov, V. M.
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p. 2191 - 2192
(2007/10/02)
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- AMIDINES. PART 13. INFLUENCE OF SUBSTITUTION AT IMINO NITROGEN ATOM ON pKa VALUES OF N1N1-DIMETHYLACETAMIDINES
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20 N1N1-Dimethylacetamidines containing alkyl, aralkyl, or substituted phenyl groups have been synthesized, and their pKa values in 95.6percent ethanol (azeotrope) measured.The pKa values obtained were correlated with Hammett ? constants.The applicability of various ? values is discussed, and it is shown that for substituents at nitrogen ?o values should be used.It has also been shown that the pKa values of amidines correlate well with the pKa values of corresponding primary amines, and that this correlation can serve for the prediction of the pKa of amidine.Comparison of the correlations for N1N1-dimethylacetamidines with those for N1N1-dimethylformamidines indicate that sensitivity of the amidine group to substitution at the imino nitrogen atom depends to a considerable degree on substitution at a functional carbon atom.
- Oszczapowicz, Janusz,Raczynska, Ewa
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p. 1643 - 1646
(2007/10/02)
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