Interaction Between Ketone and Tertiary Amine Groups

Abstract

I7apor pressure studies of trimethylamine and ketones in heptane solution have shown that unstable complexes are formed with cyclohesano~~e a t 0' and with cyclohexanone artd cyclope~~tanone a t -40'. No complex formation was observed with methylethyl ketone, diethyl ketone, or cyclopentar~one a t 0'.Robinson and co-workers (1, 2) originally suggested that there was some type of interaction between a lceto group and a tertiary arnine group in certain allcaloids having these groups in a large-membered ring, to explain the inasked reactivity of the lceto group (1) and the large displaceme~lt of its infrared stretching f r e q~~e n c y from its normal value (2). Later Leonard and co-workers (3, 4, 5) prepared a series of cyclic aza-acyloins and found evidence for transail~lular interaction in 8-(3, 5), 9-(4), and 10-(5) membered rings between the ketone and tertiary amine group. This was demonstrated by infrared and ultraviolet absorption (6) studies.Anet, Bailey, and Robinson (2) found no evidence for interaction between acetone and triethylamine or between cyclopentanone and N-methyl piperidine by infrared measurements in chloroform solution. However, the amine would preferentially interact with the chloroform (7) and hinder association between the amine and ketone, and the evidence of these worlcers cannot be considered conclusive. Thus, though interaction between lceto and amine groups within the same ring has been ainply proved, no sound evidence has been published concerning possible interaction between ketone and amine groups in separate molecules.Infrared and ultraviolet measurements are probably not the best method of observing weak interactions resulting in unstable coinplex formation, since such n~easurements must be carried out in dilute solution and cannot readily be made a t low temperatures. Moreover these measurements will only detect interactions which result in a change in the electron density of the keto group. Vapor pressure studies, however, are usually made with solutions of moderate concentration, and the lower limit of temperature is only governed by the measurable vapor pressure of one (or more) con~ponent, and the nlethod is not liinited to specific types of interaction. In this study the vapor pressure of trimethylamine above a n-heptane solution and above solutions of the lcetones, inethylethyl lcetone, diethyl ketone, cyclohexanone, and cyclopentanone in n-heptane has been measured. Trirnethylamine was chosen as a conveniently volatile, non-sterically hindered anline and ~nethylethyl lcetone and diethyl lcetone as examples of reactive and unreactive acyclic lcetones, and cyclohexanone and cyclopentanone as examples of a very reactive and a moderately reactive cyclic lcetone. The results are expressed in terms of Henry's law (8) (P solute = I<. N solute) and negative deviatioils are assumed to be due t o complex formation (8) caused by interaction between the ketones and the arnine.

Enlightening the Mechanism of Copper Mediated PhotoRDRP via High-Resolution Mass Spectrometry

“…It has been previously reported that esters can act as electron acceptors with amines as electron donors to form ion pairs when irradiated in the presence of each other. Interactions between tertiary amines and carbonyl compounds in the ground state can lead to formation of unstable complexes . It is noted that similar interactions cannot be excluded in the present case.…”

“…Interactions between tertiary amines and carbonyl compounds in the ground state can lead to formation of unstable complexes. 46 It is noted that similar interactions cannot be excluded in the present case. It is also possible that excitation of the CuBr 2 /Me 6 TREN complex can result in reduction with subsequent activation of alkyl bromide.…”

A tertiary amine in two competitive processes: reduction of graphene oxide vs. catalysis of atom transfer radical polymerization

“…S4 †) and/or from complexes of carbonyl compounds with PMDETA. 25 To further understand which component of the catalytic system was responsible for the reduction of GO, the effect of individual components was investigated. A control experiment of GO in anisole without any other compound did not lead to any change in electrical conductivity (see Table 1, entry 9).…”

Amine Solubilities: Critical Evaluation

“…However replacement of all three hydrogen atoms in ammonia by methyl groups causes significant differences in behaviour from that of the primary or secondary amine. (1) , by Halban (13) and by Wheeler and Levy (14). Wolff and Würtz (5) have investigated the IL/,/7-dime thy Ime than amine and hexane system at 223 Κ to 293 Κ over the whole of the concentration range.…”