Reactions of N-polyfluorophenylcarbonimidoyl dichlorides with primary and secondary amines. Kinetics and mechanism. Synthesis of polyfluorinated carbodiimides, chloroformamidines, guamidines and benzimidazoles.

Polyfluoroaromatic compounds with a NCClR group—a reactive type of polyfluoroarene

“…Reactions with primary aliphatic amines yield carbodiimides or guanidines; with primary aromatic amines, only guanidines are formed. An analogous picture was also observed for polyfluoroaromatic carbonimidoyl dichlorides [47,48] (Scheme 11). With a two-or three-fold molar excess of n-butyl-or tert-butylamine at 20 8C compound 10 gives the respective carbodiimides 81 in yields of up to 70%; with a four-fold excess, it leads to guanidines 82 (yields >60%).…”

“…The reaction mechanisms probably differ. As shown in [48,52,56,61] (Section 3.1.1), the reactions of 10 with aromatic amines in the absence of AlCl 3 follow a stepwise bimolecular nucleophilic addition-elimination mechanism forming a tetrahedral intermediate. The same reactions in the presence of AlCl 3 are obviously analogous to the reactions of 10 with aromatic hydrocarbons [69] (Section 3.2.1) and involve polarization of 10 by AlCl 3 and attack at the basic amine nitrogen by the positively charged intermediate.…”

“…Syntheses of guanidines 86 (Scheme 11) require elevated temperature and longer reaction time [48,52].…”

“…The mechanism of amine reactions with polyfluoroaromatic compounds having an imidoyl halogen fragment was established from kinetic data for reactions of polyfluoroaryl carbonimidoyl dichlorides and N-pentafluorophenylcarbonimidoyl dibromide (46) with primary [48,60,61], secondary [48,52,60,62], and tertiary [54,56,60] amines in the aprotic solvent acetonitrile and also for reactions of polyfluorodiarylimidoyl chlorides with tertiary amines in acetonitrile [42]. It appeared that the substitution of the first halogen atom proceeds according to the bimolecular addition-elimination mechanism via a tetrahedral intermediate ''T E AE '', although different products are formed depending on the type of amine (Scheme 12).…”

The Conversion of 4-Anilinoquinazoline- and 3-Aryl-4-imino-3,4-dihydro-quinazoline-2-carbonitriles into Benzo[4,5]imidazo[1,2-c]quinazoline-6-carbonitriles via Oxidative and Nonoxidative C–N Couplings

“…With 4-(2-bromoanilino)­quinazoline-2-carbonitrile ( 4h ) in hand, we considered a regio-controlled transition-metal-catalyzed nonoxidative coupling. A number of nonoxidative cyclization protocols are known for the transformation of N -alkyl or aryl-substituted N ′-(2-halophenyl)­benzamidines to give 1-alkyl- or 1-aryl-substituted 2-aryl-1 H -benzimidazoles; some involve transition-metal catalysis (e.g., Pd, Cu, , or Co), while others invoke base-mediated aryne intermediates , or simply intramolecular nucleophilic aromatic substitution. , …”