N-Aminations of Benzylamines and Alicyclic Amines with Nitrosoarenes to Hydrazones and Hydrazides

Abstract

Unlike other alkylamines, benzylamines upon reaction with a nitrosoarene undergo oxidation to the corresponding imines. A direct amination of benzylamines, which was difficult to achieve due to its facile oxidation, to the corresponding hydrazones is reported. A wide variety of benzylamines and N-heterocycles were reacted with nitrosoarenes to provide structurally diverse hydrazones and hydrazides, respectively. Moreover, the direct N-amination reaction was applied to the one-pot synthesis of triazoles.

UV-Light-Induced Dehydrogenative N-Acylation of Amines with 2-Nitrobenzaldehydes To Give 2-Aminobenzamides

“…Next, it happened a proton transfer procedure to produce C. 24 Subsequently, C removed proton and water to afford amide D. 24 Another benzylamine (2a) occurred nucleophilic addition with amide D to provide corresponding hydroxylamine intermediate E. 25,26 As the following, a loss of imine F of intermediate E would generate G via elimination. 25 Besides, imine F would react with 2a to release ammonia to form by-product H (detected by GCMS). 25 In addition, benzylamine (2a) could be self-coupled to get the by-product H under UV irradiation.…”

“…25 Besides, imine F would react with 2a to release ammonia to form by-product H (detected by GCMS). 25 In addition, benzylamine (2a) could be self-coupled to get the by-product H under UV irradiation. 27 At the end, hydroxylamine G might be reduced to target product 4a in this system.…”

“…23 Then, benzylamine (2a) attacks A to form intermediate B under the acidic environment. Next, a proton transfer procedure occurs to produce C. 24 Subsequently, C loses a proton and water to afford amide D. 24 Nucleophilic addition of another benzylamine (2a) to amide D provides the corresponding hydroxylamine intermediate E, 25,26 and the loss of imine F from intermediate E generates G via elimination. 25 Imine F reacts with 2a to release ammonia to form byproduct H (detected by GC/MS).…”

Condensation-Based Methods for the C–H Bond Functionalization of Amines

“…Jana and coworkers reported an unusual N-amination of amines that proceeds with concurrent α-oxidation (Scheme 56). 103 Specifically, pyrrolidine engages nitrosobenzenes in the presence of 2,4-dichlorobenzoic acid (DCBA) to provide cyclic hydrazides such as 110. THIQ is also a viable substrate.…”

PIII/PV═O-Catalyzed Intermolecular N–N Bond Formation: Cross-Selective Reductive Coupling of Nitroarenes and Anilines

“…Taken together with literature precedent, these experimental findings are best accommodated by an autotandem catalytic reaction mechanism for the intermolecular N–N reductive coupling involving two sequential and mechanistically distinct reduction events, as illustrated in Figure . In a first catalytic stage, the nitroarene substrate is deoxygenated by P III phosphetane 1 , giving a nitrosoarene intermediate ( Int-2 ) by a [3+1]/retro-[2+2] sequence via Int-1 as previously described. , Once formed, nitrosoarene Int-2 advances off-cycle to azoarene Int-3 by dehydrative condensation. − The equivalent of water thus released proves critical for the second catalyzed reduction event; azoarene Int-3 is reduced by 1 in the presence of carboxylic acid via hydrazinylphosphonium Int-4 , − whose hydrolytic decomposition depends on adventitious water for release of the desired hydrazine product and phosphetane oxide 1 ·[O] . A common feature uniting both catalytic cycles is the hydrosilane-mediated reductive turnover of the P V O catalyst 1 ·[O] to regenerate the reactive P III state ( 1 ), a mechanistic step that is kinetically facilitated by the presence of the small ring in the organophosphorus catalyst.…”