Trimethylamine, catalytic reactions

Although a variety of amines, particularly trimethylamine and n-butylamine have widely been used as poisons in catalytic reactions and for surface acidity determinations (20), comparably few spectroscopic data of adsorbed amines are available. As with ammonia, coordinatively adsorbed amines held by co-ordinatively unsaturated cations have preferentially been found on pure oxides (176, 193-196), whereas the protonated species were additionally observed on the surfaces of silica-aluminas and zeolites (196-199). However, protonated species have also been detected on n-butylamine adsorption on alumina (196) and trimethylamine adsorption on anatase (176) due to the high basicity of these aliphatic amines. In addition, there is some evidence for dissociative adsorption of n-butylamine (196) and trimethylamine (221) on silica-alumina. Some amines undergo chemical transformations at higher temperatures (195, 200) and aromatic amines, such as diphenylamine, have been shown to produce cation radicals on silica-alumina (201, 201a). 

In general, the acetylenic triple bond is highly reactive toward hydrogenation, hydroboration, and hydration in the presence of acid catalyst. Protection of a triple bond in disubstituted acetylenic compounds is possible by complex formation with octacarbonyl dicobalt [Co2(CO)g Eq. (64) 163]. The cobalt complex that forms at ordinary temperatures is stable to reduction reactions (diborane, diimides, Grignards) and to high-temperature catalytic reactions with carbon dioxide. Regeneration of the triple bond is accomplished with ferric nitrate [164], ammonium ceric nitrate [165] or trimethylamine oxide [166]. 

Recently Tanabe and co-workers have found that several alcohols were smoothly and efficiently tosylated using tosyl chloride/triethylamine and a catalytic amount of trimethylamine hydrochloride as reagents.6 Compared with the traditional method using pyridine as solvent, this procedure has the merit of much higher reaction rates, and it avoids the side reaction in which the desired tosylate is converted into the corresponding chloride. 

Another catalytic application emanating from the Hieber base reaction was developed by Reppe and Vetter [108]. They showed that 1-propanol 126 could be generated by treatment of ethylene 125 with catalytic amounts of Fe(CO)5 78 under CO-pressure and basic reaction conditions (Scheme 33). Thereby, trimethylamine and V-alkylated amino acid derivatives mrned out to be optimal bases for this reaction. Like ethylene 125, propylene could be transferred mainly to 1-butanol diolefins like butadiene only reacted to monoalcohols. By employing these reaction conditions to olefins in the presence of ammonia, primary or secondary amines, mono-, di-, and trialkylamines were obtained whose alkyl chains were elongated with one carbon atom, compared to the olefins. 

Material 1 was also treated with 3-bromopropyltrichlorosilane to yield a propyl tether with a bromo-head group (4). Substitution with either trimethylamine or triethylamine to form the corresponding quaternary ammonium species, followed by ion exchange with potassium perruthenate afforded the catalytic species (5) and (6) respectively. The black solid 5 was found to be an equally efficient catalyst for the oxidation reactions and 6 was found to be a more highly active recoverable and reusable... 

A catalytic system, based on TEMPO and Cu(II), has been developed for the selective oxidation of primary alcohols to aldehydes under very mild conditions. Cu(II) is generated in situ by oxidation of elemental copper and chelated by means of 2,2 -bipyridine. The reaction is dependent on pH. New insights into the currently accepted mechanism have been discussed.76 Allylic and benzylic alcohols are selectively oxidized with trimethylamine N-oxide in the presence of cyclohexa-1,3-dieneiron carbonyl.77... 

The catalytic action of trimethylamine [84] is necessary in order to perform the acylation reaction successfully. A 200-jul volume of a 10-2 M benzene solution of the amine containing an internal standard (p-dibromobenzene or 1 -bromonaphthalene) is mixed with 200 (xl of 0.3 M trimethylamine in benzene and 25 fi of anhydride. After 15 min at... 

H4Ru4(CO),2] were shown to transform propene into butyraldehyde under a partial CO pressure of 28 bar (PcjH. 12 bar) at 100°C for 10 hours in the presence of a large excess of aqueous trimethylamine. These catalytic systems are more active for the water gas shift reaction (turnover frequency 340 hour" ) than for the production of 0x0 compounds( 12 hour" ). However, no indications about the nature of the ruthenium species produced in basic media were given. 

Benzamides (N-Bz) are formed by the reaction of amines with benzoyl chloride in pyridine or trimethylamine. The group is stable to pH 1-14, nucleophiles, organometallics (except organolithium reagents), catalytic hydrogenation, and oxidation. It is cleaved by strong acids (6N HCl, HBr) or diisobutylaluminum hydride. ... 

Coupling of the free amino derivative with Fmoc protected commercially available amino acids (alanine and phenylalanine) was accomplished via standard reaction conditions activated by DCC in anhydrous tetrahydrofiiran (THF) solution. Deprotection of synthesized peptides by treatment with aqueous methanol solution and catalytic amount of trimethylamine produced a new class of 5-thio-carbo peptides in 86% yield. This particular family of new stable peptidomimetics is conveniently protected and could be used for further additional functionalization at the primary -OH at C-6 of the thioglucose moiety. Further deprotection of the 1,2-0-isopropylidene block created another... 

The catalytic activity of tertiary amines in the phenyl isocyanate-butanol reaction falls off as the size of the substituent groups in tertiary amines increases [140]. The base strengths (pKa) of trimethylamine, ethyldimethylam-ine, diethylmethylamine, triethylamine, and triethylenediamine are 9.9, 10.2, 10.4, 10.8, and 8.2, respectively, whereas the relative catalytic activities of those are 2.2, 1.6, 1.0. 0.9, and 3.3, respectively [140]. 

Alternatively, a mild and efficient one-pot electrophilic aromatic substitution/ oxidative cyclization without isolation of the intermediate complexes 36 has been achieved using air as oxidizing agent (mode B in Scheme 12). Thus, reaction via mode B leads to tricarbonyl(ri" -4a,9a-dihydrocarbazole)iron complexes 37, which on demetalation with trimethylamine A(-oxide and subsequent catalytic dehydrogenation provide the carbazoles 40. The naturally occurring carbazole... 

A significant advance in the Pauson-Khand reaction was made by the discovery that various additives, such as tertiary amine A-oxides, promote the cycloaddition reaction. For example, treatment of the dicobalt complexed alkyne 187 with trimethylamine A-oxide at only 0 °C provides the cyclopentenone 188 in good yield (1.192). More recent advances have been made in catalytic Pauson-Khand reactions. " Only 3 mol% of dicobalt octacarbonyl [Co2(CO)8] under one atmosphere of CO effects the formation of the cyclopentenone 188 from the alkyne 189 in benzene at 70 °C (an improvement in the yield to 90% was achieved in the presence of the additive Bu3P=S) (1.193). " ... 

Although amines do not have to be in the free-base form for acylation by perfluoroacyl anhydrides, and derivatize smoothly even as their salts, some workers have included bases for catalytic purposes, and also to remove acid formed during the reaction, in addition to a solvent. In one recipe, the amine is dissolved in benzene (500 y ) and trimethylamine is added (100 fi of a 0.05 M solution in benzene) followed by 10 1 of anhydride, and the reaction is allowed to go to completion at room temperature. With the low concentration of anhydride this may take some hours. Excess anhydride is removed by washing with 3M ammonium hydroxide and the benzene solution is dried before GC analysis (80, 81]. In a similar procedure, the rather uncommon chlorodi-fluoroacetic anhydride is used. Here the base, extracted from its biological matrix, is dissolved in chloroform (20 fi ) and derivatized with triethylamine (1.5 yl) and the anhydride (3 y ) at 50 °C for 30 min. Excess reagent is neutralized with alkali and the derivatives are concentrated to dryness and taken up in toluene for GC analysis [82]. Trichothecenes (250 mg) are treated with TFAA and about 10 mg of solid sodium bicarbonate for 30 minutes at 80 C [83]. Alternatively, 0.5 ml of 10% acetonitrile in toluene is added followed by 100 y of triethylamine and 100 ul of PFPA. The reaction is carried out at 60 C for 15 minutes, and the reaction solution is washed with two 0.5 ml portions of 5% aqueous ammonia and one 0.4 ml portion of water to remove the surplus reagents [84]. 

In order to develop catalytic effects of cyclodextrins for bimolecular reactions, it needs to include two guest molecules simultaneously in a cyclodextrin (CD) cavity. Several examples of cyclodextrin-catalyzed bimolecular reactions have been reported. Rideout and Breslow have found that Diels-Alder reactions of cyclo-pentadiene with butenone, cyclopentadiene with acrylonitrile, and anthracene-9-carbinol with N-ethylmaleimide in water are markedly accelerated by 3-cyclodextrin (3-CD) (1). Komiyama and Hirai have reported site-selective Reimer-Tiemann reactions of phenols in cyclodextrin solutions (2). In most of these reactions, however, each substrate molecule is relatively small so that a 3-CD cavity may include simultaneously an additional reactant molecules. We found previously that the fluorescence quenching of pyrene and naphthalene by trimethylamine (TMA) or dimethylamine (DMA) in water is catalyzed by g-CD (3) Since the pyrene molecule is too large to be incorporated completely in the 3-CD cavity, it has been assumed that pyrene binds to a rim of the CD cavity to form a pyrene-capped CD complex and a remain-... 

Except for seemingly inaccxirate data on trimethylamine given in the International Critical Tables (1928)/ data are remarkably sparse yet thousands of papers on the properties of these amines have appeared. The data presented herein show the need to consider the intermolecular effects which may influence the course of reactions in organic chemistry. Catalytic effects are especially to be looked for. 

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