99969-04-7Relevant articles and documents
Synthesis of secondary amides from N-Substituted amidines by tandem oxidative rearrangement and isocyanate elimination
Debnath, Pradip,Baeten, Mattijs,Lefvre, Nicolas,Van Daele, Stijn,Maes, Bert U. W.
supporting information, p. 197 - 209 (2015/03/03)
In this work an efficient tandem process transforming N-substituted amidines into secondary amides has been described. The process involves N-acylurea formation by reaction of the substrate with bis(acyloxy)(phenyl)-λ3-iodane followed by isocyanate elimination. The periodinane reagents are obtained from the commercially available phenyl-iodine(III) diacetate [PhI(OAc)2, (PIDA)] by ligand exchange with carboxylic acids. The N-substituted amidine substrates are easily synthesized from readily available nitriles. The method is applicable for secondary amide synthesis, based on both aliphatic and (hetero)aromatic amines, including challenging amides consisting of sterically hindered acids and amines. Moreover, the protocol allows one to combine steric bulk with electron deficiency in the target amides (aniline based). Such compounds are difficult to synthesize efficiently based on classical condensation reactions involving carboxylic acids and amines. Overall, the synthetic protocol transforms a nitrile into a secondary amide in both aliphatic and (hetero)aromatic systems.
A simple and efficient procedure for the Beckmann rearrangement of oxtme using bis-(Trichloromethyl) carbonate/DMF
Su,Zhang,Li,Li
experimental part, p. 543 - 550 (2009/04/05)
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The oxidative rearrangement of furan-2-carboximidamides: Preparation and properties of 2-acylaminofurans
Bobosikova,Clegg,Coles,Dandarova,Hursthouse,Kiss,Krutosikova,Liptaj,Pronayova,Ramsden
, p. 680 - 689 (2007/10/03)
Oxidation of furan-2-carboximidamides 8 by (dicarboxyiodo)benzenes gives N1-acyl-N1-(2-furyl)ureas 9 via rearrangement to a carbodiimide. Thermolysis of eleven ureas 9 gave the corresponding 2-acylaminofurans 10, which cannot be made from the free amines owing to their high instability. When oxidation of the corresponding benzo[b]furan derivatives 12 was investigated a new type of product was isolated, in addition to the expected ureas 14, and these were shown to be benzo[4,5]furo[2,3-d]pyrimidine derivatives 15. The mechanism of formation of these products must involve reaction of the carbodiimide intermediate with the amidine precursor and cyclisation of the resulting guanidine derivatives 19. The corresponding tetraphenylguanidine 21 was prepared and underwent thermal cyclisation but the quinazoline derivative formed 23 was shown to occur via an alternative cyclisation mechanism. The structures of cyclisation products 15 and 23 were confirmed by X-ray crystallography. N-(2-Furyl)acetamide 10a readily undergoes cycloaddition reactions with electron-deficient alkynes to give phenols after spontaneous ring opening. Observed regioselectivity is in agreement with the results of AM1 molecular orbital calculations. Reaction of the amide 10a with Lawesson's reagent gave the thioamide 26.
