One-pot reductive monoalkylation of nitro aryls with hydrogen over Pd/C

Comparative Theoretical Study of Adsorption and Dehydrogenation of Formic Acid, Hydrazine and Isopropanol on Pd(111) Surface

“…Several compounds, such as formic acid (or formate), hydrazine and isopropanol, have been selected as hydrogen donors [3][4][5][6][7], and Pd is a commonly used catalyst. All the experiments indicated that in Pd catalyzed CTH, formic acid and hydrazine were both effective hydrogen donors, while isopropanol was less active.…”

One-Pot Procedures for the Formation of Secondary Aryl Amines from Nitro Aryls

“…25,26 The equilibrium for this formation was far towards ethanol, however, due to the presence of the primary amine functioning as a trapping agent for the aldehyde a relatively large yield (41%) of the secondary amine could be isolated after 48 hours. 23 No trace of the corresponding diethyl tertiary amine could be found in the product mixture. We thought we could take advantage of the fact that the tertiary amine was not formed under these conditions and see if we could develop a useful reaction by adding the alkylation agent, viz.…”

“…Our entry into this type of chemistry was by coincidence due to a byproduct (secondary amine 4) formed during reduction of the corresponding nitro aryl [ethyl (4-methoxy-3-nitrophenyl)acetate] to the corresponding primary amine under an atmosphere of hydrogen gas over Pd/C (10%) at room temperature in ethanol. 23 The primary amine was needed for the formation of the corresponding aryl azide which was used for photochemistry studies. 24 The formation of secondary ethyl amine 4 was possible due to small quantities of acetaldehyde formed via oxidative addition of palladium to the alcohol followed by β-hydride elimination.…”

“…And indeed, when ethyl (4-methoxy-3-nitrophenyl)acetate was stirred under an atmosphere of hydrogen gas over Pd/C (10%) in the presence of 1.1 equivalents of acetaldehyde at room temperature the corresponding secondary ethyl amine was formed in 98% isolated yield in the course of three hours. 23 A range of secondary amines could be formed by utilizing this procedure ( Figure 2). Only when one equivalent of formaldehyde (37 wt% in water) was used as the alkylation agent during the reductive monoalkylation of ethyl (4-methoxy-3-nitrophenyl)acetate was some (16%) of the corresponding tertiary amine formed together with 61% of the desired product.…”

Pd/C‐catalyzed Reductive Mono‐N‐alkylation of Nitrophenol Derivatives in One‐pot Way

“…4 Similarly, reductive mono-N-alkylation of nitro-arenes with aldehydes can be carried out in the presence of hydrogen over Pd/C catalyst. 5 Nitrobenzene derivatives can react with α-ketoester to form the N-alkylated aniline. 6 However, little attention has been paid to the synthesis of mono-N-alkylated aminophenols.…”