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Synthesis of amidines
2,2,2-Trifluoro- and trichloroethyl imidates, which are easily prepared by reaction of a nitrile and a trihaloethanol in the presence of HCl, are excellent reagents for the preparation of amidines under mild reaction conditions.
S. Caron, L. Wei, J. Douville, A. Ghosh, J. Org. Chem., 2010, 75, 945-947.
A method for the Pd-catalyzed N-arylation of both aryl and alkyl amidines with a wide range of aryl bromides, chlorides, and triflates proceeds in short reaction times and with excellent selectivity for monoarylation. A one-pot synthesis of quinazoline derivatives via Pd-catalyzed N-arylation followed by addition of an aldehyde to the crude reaction mixture is also demonstrated.
M. A. McGowan, C. Z. McAvoy, S. L. Buchwald, Org. Lett., 2012, 14, 3800-3803.
Copper-catalyzed cross-coupling reactions of amidine salts with aryl iodides give monoarylated amidines in good yields under ligand-free conditions. DMF was the superior solvent for the N-arylation of benzamidines, while MeCN was used in the formation of N-aryl amidines in good yield.
M. Cortes-Salva, C. Garvin, J. C. Antilla, J. Org. Chem., 2011, 76, 1456-1459.
Microwave reactions of primary and secondary amines with imidoylbenzotriazoles gave various polysubstituted amidines in good yields. Convenient preparations of a variety of amides and imidoylbenzotriazoles have also been developed using microwave irradiation under mild conditions and short reaction times.
A. R. Katritzky, C. Cai, S. K. Singh, J. Org. Chem., 2006, 71, 3375-3380.
A catalyst-free hydroamination of N,N-disulfonyl ynamides with amines gives N-sulfonylamidines. Alkyl amines react with N,N-disulfonyl ynamides under mild conditions, whereas aryl amines require higher temperatures.
Y. Kong, L. Yu, J. Cao, Synthesis, 2014, 46, 183-188.
Organic azides are easily and chemoselectively reduced to the corresponding amines by reaction with dichloroindium hydride under very mild conditions. γ-Azidonitriles give pyrrolidin-2-imines in an outstanding cyclization.
L. Benati, G. Bencivenni, R. Leardini, D. Nanni, M. Minozzi, P. Spagnolo, R. Scialpi, G. Zanardi, Org. Lett., 2006, 8, 2499-2502.