Studien über den Mechanismus chemischer Reaktionen, XXIV. Vergleichende Hydrierungen von RCN zu RCH₃ mit gebundenem bzw. elementarem Wasserstoff

Abstract

Die friiher beschriebenen Hydrierungen von Nitrilen mit gebundenem Wasserstoff und Pd/ Kohle gelingen bei ausreichend hohcr Temperatur auch mit elementarem Wasserstoff. cr-Cyan-zimtsaureester werden in cr-Methyl-hydrozimtsaureester iibergefiihrt, aus denen das pharmakologisch wichtige 2-Amino-I -phenyl-propan und dessen Derivate gut zuganglich sind. Relativ schwer gelingt die Hydrierung von R-CN zu R-CHJ, wenn R ein unsubstituierter, langkettiger aliphatischer Rest ist. Es wird versucht, den Mechanismus der Umsetzungen zu klaren.Mit Al-p-Menthen, a-Phellandren oder Limonen und Pd/Kohle werden Cyanreste in Methylgruppen umgewandelt I ) , wobei der Stickstoff als NH3 austritt. Von den 1-6H

Simple and Efficient One-Step Conversion of Benzonitrile into Methylarene under Mild Conditions

“…This strongly suggests that the mechanism of nitrile reduction proceeds via a primary amine intermediate as reported by Kindler and Lührs. 4 Moreover, when 4-methoxybenzylamine was submitted to these conditions, we observed the formation of the methyl group.…”

“…The reduction of this functionality into a methyl group has been the object of very few publications. 2 In fact, the methods reported in literature often use special apparatus, 3 demand high-pressure hydrogen, 4 or require particular manipulations. 5 Reported procedures work well, but are limited to very specific substrates and require extensive purification.…”

“…ported methods precede using a palladium-based catalyst. 4,5 We then decided to compare our method with the closest one regarding the conditions, that is, the methodology developed by Brown and Foubister 5 using ammonium formate as a hydrogen source. Their methodology, as ours, requires a palladium catalyst, proceeds at room temperature, and does not require special glassware.…”