Dimerization amines

The dimeric [Ru(CO)o(OCOCH3) (pip)]2 complex (2) may be used at the appropriate ruthenium molarities to reproduce exactly the uptake plots observed with the polymeric catalyst. Solution IR measurements in regions of maximum activity for both 1- and 2-catalyzed systems showed the presence of the amine dimers which could be readily precipitated at any stage of the catalytic carbonylation by adding water. 

The proposed mechanism for exciplex quenching involves formation of a triplex l(t-lT(R3N)2 ) in which the amine dimer cation radical (62) has formed a 3-electron a bond. 

Stabilization of the exciplex by the estimated bond energy of the amine dimer cation radical, 0.7 eV (129), would render intersystem crossing to form t endothermic by 0.2 eV as shown in Fig. 9 and enhance the rate of nonradiative decay. 

Yamdagni, R., and Kebarle, R, Gas-phase basicities of amines. Hydrogen bonding in proton-bound amine dimers and proton-induced cyclization of a,a-diamines, J. Am. Chem. Soc. 95, 3504-3510(1973). 

The reaction of the /V,/V-diethyl-l, 3-dichlorodithiatriazin-5-amine dimer lc with norbomadiene in the presence of triphenylstilbane yielded 24% of compound 4b.7... 

An excess of norbomadiene (5 mL) was added to a solution of 7V,7V-diisopropyldithiatriazin-5-amine dimer Id (0.30 g, 1.4 mmol) in Et20 (30 mL) at — 20 °C. After 2 h at 23 X solvent and excess of norbomadiene were removed under vacuum to give a sticky yellow residue. Recrystallization (hexane) at — 20 X gave pale-yellow crystals of compound 4c yield 0.25 g (57%) mp 145 °C. 

Katritzky et al. have prepared a-amino carbanions from tosyl methyl amines. The transformation was achieved by treatment with 2 equiv of Sml2 [82] in the presence of an electrophile (Scheme 38). In the absence of HMPA the use of iso-butyraldehyde as the electrophile gave only the amine dimer (98%). However, the addition of 5% of HMPA resulted in a 67% yield of the desired product (62%) with a minor amount of diamine (17%). The formation of the hydroxy amine probably involves a carbanion intermediate whereas coupling gives the diamine. 

Indophenols from 2 p-aminophenol molecules via di-(p-hydroxyphenyl)amines Dimerization with elimination of ammonia... 

The amination of ketenes to produce amides (see Scheme 1) has been subjected to a variety of computational methods, including several treatments of the solvent, with explicit roles for actively participating amine and water molecules. All the results favour a two-step process with initial addition to the C=0 bond, rather than a concerted reaction involving the C=C bond. The former involves a 1-amino-1-hydroxy ene intermediate (6), formally the enol of the amide. Inclusion of a second amine molecule lowers the barrier to the two-step reaction. Replacing the second amine with a water molecule lowers it even further, an effect which should be even greater when water is the bulk solvent. Some experimental evidence is presented for the highly hindered substrates, bis(mesityl)ketene and bis(pentamethylphenyl)ketene. Addition of primary or secondary amines clearly shows, from IR and UV spectra, the build-up and subsequent tautomerization of the intermediate enols. The kinetics of these more hindered substrates are first order in amine this is not inconsistent with the theoretical results, as such hindered ketenes may only react rather slowly with amine dimer, which is also in low concentration under the conditions used. 

When benzylamine was used instead of a seeondaiy amine, dimeric compound 18 was produced in 82% yield (100 °C, 3 h, then reflux, 1 h). 

Dissociation rate constants of ions at atmospheric pressure have been obtained by ion mobility spectrometry. The time frame of such experiments is in the millisecond range. Dissociation rates of proton-bound amine dimer ions, for example, have been measured recently. 

Chem. Descrip. Di (behenamidopropyl dimethyl amine) dimer dilinoleate Ionic Nature Cationic... 

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