Methanol amine oxides

The mixture is filtered into a 500-ml round-bottom flask, and methanol and water are removed by distillation under vacuum (bath temperature 50-60°) until the residual amine oxide hydrate solidifies. The flask is fitted with a magnetic stirrer and a short Vigreux column, and the receiving flask is cooled in a Dry Ice-acetone bath. The flask... 

Archibald and co-workers used a similar strategy of amine oxidation, followed by oxidative nitration, for the conversion of 5,10-diaminodispiro[3.1.3.1]decane to 5,5,10,10-tetranitrodispiro[3.1.3.1]decane (21). 5,10-Diaminodispiro[3.1.3.1]decane was prepared from the redaction of the corresponding oxime (19) with sodium in liquid ammonia-methanol. 5,10-Dinitrodispiro[3.1.3.1]decane (20) nndergoes oxidative nitration to give 5,5,10,10-tetranitrodispiro[3.1.3.1]decane (21) in 64 % yield. 

In industrial practice, three-phase catalytic reactors are often used, with gases like such as H2, H2O, NH3 or O2 as reactants. The process can be classified on the basis of these gases as hydrogenation, hydration, amination, oxidation, etc [3]. Among these processes, hydrogenation is by far the most important multiphase catalytic reaction. Recently, liquid- -phase methanol synthesis and the Fischer-Tropsch process were commercialized respectively... 

Fig. 24 Ru(II)/ROOH system in methanol for oxidation of tertiary amines...

The bulk material may ignite or explode in storage. Traces of water may initiate the reaction. A rapid exothermic decomposition above 175°C releases oxygen and chlorine. Moderately explosive in its solid form when heated. Explosive reaction with acetic acid + potassium cyanide, amines, ammonium chloride, carbon or charcoal + heat, carbon tetrachloride + heat, N,N-dichloromethyl-amine + heat, ethanol, methanol, iron oxide, rust, 1-propanethiol, isobutanethiol, turpentine. Potentially explosive reaction with sodium hydrogen sulfate + starch + sodium carbonate. Reaction with acetylene or nitrogenous bases forms explosive products. 

Cyclization to the benzo[c]phenanthridine (127) competes with rearrangement to the ring-expanded product (128) on irradiation of the amine oxide (129). A practical synthesis of the chlorin macrocycle (130) has been developed by irradiation of the seco-compound (131) in tetrahydrofuran containing TFA and Hiinig s base this is thought to take place by photocyc-lization of the ISrr-tautomer (132), followed by elimination of methanol. Analogous approaches have been employed in the syntheses of ( )-bonellin dimethyl ester and 20-methyl- and 20-cyano-isobacteriochlorins. " ... 

Oxidations with m-chloroperoxybenzoic acid are carried out in solutions in hexane, dichloromethane, chloroform, methanol, or tetrahydro-furan at temperatures ranging from -78 to 40 C. The applications of m-chloroperoxybenzoic acid are epoxidation [287, 314, 315, 316] the Baeyer-Villiger reaction [286, 315, 317, 378] and the oxidation of primary amines to nitro compounds [379], of tertiary amines to amine oxides [320], of sulfides to sulfoxides [327, 322, 323, 324], and of selenides to selenones [325]. Secondary alcohols are oxidized to ketones in the presence of hydrogen chloride [326], and acetals are oxidized to esters with boron trifluoride etherate as a catalyst [327]. The addition of potassium fluoride to reaction mixtures facilitates product isolation, because both m-chloroben-zoic acid and the unreacted m-chloroperoxybenzoic acid are precipitated... 

The purpose of preparing aliphatic amine oxides is usually their thermal decomposition to cis alkenes and N,N-dialkylhydroxylamines (Cope rearrangement) [156, 161, 1187]. Thus A, A -dimethylcyclohexylmethylamine is oxidized with 30% hydrogen peroxide in methanol to its oxide, whose decomposition at 90-100 °C at 10 mm of Hg and at 160 °C for 2 h furnishes 79-88% of methylenecyclohexane and 78-90% of A, A -dimethylhydroxyl-amine [161], Another example is the preparation of cw-cyclooctene from dimethylcyclooctylamine (equation 502) [1187]. 

In a special case of tertiary amine oxidations, the electrogenerated diiminium ion obtained from the indole alkaloid cantharanthine couples in the 16-position with the electron-rich aromatic subunit of vindoline in the 10-position to give the highly cytostatic anhydrovinblastine. In the presence of methanol, the methoxy group is introduced in the 16-position, yielding, after a follow-up reduction, 16-methoxyclea-vamine [18]. 

It is reported in the early literature that unsymmetrical amine oxides or those of high molecular weight cannot be prepared by the action of ozone on the amine. This study shows that an unsymmetrical amine oxide, such as N-ethylpiperidine oxide, and a symmetrical high molecular weight amine oxide, such as tri-n-hexylamine oxide, can be prepared by ozonization in methanol solution. 

The experimental technique consisted of ozonization at dry ice temperature in a solvent such as methanol, in which both the picric acid and amine oxide were soluble, and addition of the cold solution of amine oxide to the alcoholic solution of picric acid. On standing in the refrigerator, crystals of the picrate separated from the solution. These crystals were filtered, dried under a vacuum, and weighed. Then they were purified from methanol and analyzed. 

Reductive desulfurization of the dithioketals 5.14 and 5.15 is performed under the same conditions as for thioethers [G02] LAH in the presence of copper salts or borohydrides in the presence of nickel salts (Figure 5.8). The deoxygenation of tertiary amine-oxides such as 5.16 and 5.17 can be performed with borohydride exchange resin-copper sulfate in methanol at room temperature or under reflux. This reaction tolerates other functional groups such as carbon-carbon double bonds, chlorides, epoxides, esters, amides, nitriles, sulfoxides, and sulfones [SA4] (Figure 5.8). 

The best known of these is the ozonation of tertiary amines to amine oxides (II) (i). Henbest and Stratford (11) and Shulman (17) have shown that competing with this is an ozone attack on the alpha position of an alkyl side chain to produce various decomposition products of III. Henbest (11) showed that amine oxide formation is favored in chloroform and methanol, while side chain oxidation is predominant in hydrocarbon solvents. Also of considerable interest are the reported conversions, during ozonation, of phenylenediamines to Wursters salts (VII) (8, 14), of liquid ammonia to ammonium ozonate (VA) at a low temperature 18), and of amines to amine hydrochlorides (VB) in chlorinated hydrocarbon solvents 17, 19), Finally, an early report states that azobenzene and quinone are obtained upon ozonation of aniline (15). 

Recently, Makosza et al. reported that the reaction of different pyridine and quininolin oxides HFP carried out in the presence of methanol, amines, or thiols leads to the formation of the corresponding functional derivatives 91-93 (Fig. 7.31). ... 

Rates are fastest in polar aprotic solvents such as THF, diethyl ether and acetone but are slower in alcohols such as -butyl alcohol and methanol. Steric hindrance about the nitrogen also plays a role. The yields of amine oxide formed from tertiary amines increase in the order (CH3)2N( -Ci2H26) > (C2Hs)3N > (C4H9)3N. 

Suppose we consider some very weakly basic compounds, such as ketimines, phosphines, and oxiranes. A very interesting method of dealing with oxiranes was developed by Durbetaki. The oxirane was reacted with hydro-bromic acid to form the bromohydrln. This type of reaction has long been known using hydrochloric acid, but in that medium the reaction takes approximately three hours. In glacial acetic acid, the reaction is enough to allow you to titrate directly at normal speed. You can get an end point potentiometrically or with an indicator. In fact, if you have a mixture of amine and oxirane, you can get two potentlometric breaks, the first for the amine and the second for the oxirane. Amides, phosphene oxides, triphenyl methanol, and amine oxides are very weak bases and cannot be titrated in glacial acetic acid under ordinary conditions. However, they can be titrated if one uses acetic anhydride as solvent, or if one uses a solvent that is mixed with acetic anhydride. Why does acetic anhydride work There are two reasons. First, it removes the last trace of water from the solution secondly, perchloric acid in the presence of acetic anhydride forms the ion CHsCO". Since this is an extremely reactive substance, one can titrate very weak bases. 

Henrich developed a comprehensive TLC method for identification of surfactants in formulations (4). She specified two reversed-phase and four normal phase systems, with detection by fluorescence quenching, pinacryptol yellow and rhodamine B, and iodine. Prior to visualization, one plate was scanned with a densitometer at 254 nm, and UV reflectance spectra were recorded for each spot detected. Tables were prepared showing the Rf values of 150 standard surfactants in each of the six systems, along with the reflectance spectra and response to the visualizers. This system allows for systematic identification of compounds of a number of surfactant types (LAS, alcohol sulfates and ether sulfates, alkane sulfonates, sufosuccinate esters, phosphate compounds, AE, APE, ethoxylated sorbi-tan esters, mono- and dialkanolamides, EO/PO copolymers, amine oxides, quaternary amines, amphoterics and miscellaneous compounds). Supplementary analysis by normal phase HPLC aided in exactly characterizing ethoxylated compounds. For confirmation, the separated spots may be scraped from one of the silica gel plates and the surfactant extracted from the silica with methanol and identified by IR spectroscopy. 

Amine oxides and various amphoteric surfactants can be determined by reversed-phase HPLC using a Cis column with a mobile phase of 90 10 or 80 20 methanol/water. Differential refractive index detection is suitable (179)... 

Reactions with Organic Compounds. Tetrafluoroethylene and OF2 react spontaneously to form C2F and COF2. Ethylene and OF2 may react explosively, but under controlled conditions monofluoroethane and 1,2-difluoroethane can be recovered (33). Benzene is oxidized to quinone and hydroquinone by OF2. Methanol and ethanol are oxidized at room temperature (4). Organic amines are extensively degraded by OF2 at room temperature, but primary aHphatic amines in a fluorocarbon solvent at —42°C are smoothly oxidized to the corresponding nitroso compounds (34). 

PMMA is not affected by most inorganic solutions, mineral oils, animal oils, low concentrations of alcohols paraffins, olefins, amines, alkyl monohahdes and ahphatic hydrocarbons and higher esters, ie, >10 carbon atoms. However, PMMA is attacked by lower esters, eg, ethyl acetate, isopropyl acetate aromatic hydrocarbons, eg, benzene, toluene, xylene phenols, eg, cresol, carboHc acid aryl hahdes, eg, chlorobenzene, bromobenzene ahphatic acids, eg, butyric acid, acetic acid alkyl polyhaHdes, eg, ethylene dichloride, methylene chloride high concentrations of alcohols, eg, methanol, ethanol 2-propanol and high concentrations of alkahes and oxidizing agents. 

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