Ammonia methyl ether

For example, the action of a-thiocyanatoacetone on ammonia in ether solution gives 4-methyl-2-aminothiazole but in very low yield (137). Methylamine in ether at 0°C gives in a first step S-acetonyl N-methylisothiourea (196) in 80% yield (Scheme 102) (137). The cycliza-tion of this intermediate occurs either after a prolonged rest at room temperature, either by fusion or by heating with dilute hydrochloric acid to afford the 4-methyl-2-methylaminothiazole (197). 

Heat-SensitiZingProcess. Another process used to make latex mbber articles of thicker section involves sensitizing the compound so that it coagulates when heated to a given temperature, then using heated molds to build the article to the desired thickness. Ammonia-preserved latex is used in this process, and polyether, polythioether, or poly(vinyl methyl ether) (PVME) can be used as heat-sensitizing agents. 

The styrene double bond in 9(ll)-dehydroestradiol 3-methyI ether (1) or its 8-dehydro counterpart is reduced by potassium or lithium in ammonia without affecting the aromatic ring estradiol 3-methyl ether (2) is formed from both compounds. Reduction of the corresponding 17-ketones occurs with partial or complete reduction of the carbonyl group. Lithium... 

The A-ring of the 17-ol (25) derived from equilenin 3-methyl ether is reduced rapidly under Birch reduction conditions, since the 1,4-positions are unsubstituted. The B-ring is reduced at a much slower rate, as is characteristic of aromatic compounds in which 1,4-reduction can occur only if a proton enters an alkylated position. Treatment of (25) with sodium and t-butyl alcohol in ammonia reduces only the A-ring to afford the corresponding 1,4-dihydro compound in over 85% yield.On the other hand,... 

A remarkable feature of the Birch reduction of estradiol 3-methyl ether derivatives, as well as of other metal-ammonia reductions, is the extreme rapidity of reaction. Sodium and -butyl alcohol, a metal-alcohol combination having a comparatively slow rate of reduction, effects the reduction of estradiol 3-methyl ether to the extent of 96% in 5 minutes at —33° lithium also effects complete reduction under the same conditions as is to be expected. Shorter reaction times were not studied. At —70°, reduction with sodium occurs to the extent of 56 % in 5 minutes, although reduction with lithium is virtually complete (96%) in the same time. (The slow rates of reduction of compounds of the 5-methoxytetralin type is exemplified by 5-methoxy-tetralin itself with sodium and f-butyl alcohol reduction occurs to the extent of only 50% in 6 hours vs. 99+% with lithium.) The iron catalyzed reaction of sodium with alcohols must be very fast since it competes so well with the rapid Birch reduction. One cannot compensate for the presence of iron in a Birch reduction mixture containing sodium by adding additional metal to extend the reaction time. The iron catalyzed sodium-alcohol reaction is sufficiently rapid that the aromatic steroid still remains largely unreduced. 

The solubility of many steroids in ammonia-tetrahydrofuran-/-butyl alcohol is about 0.06 A/, a higher concentration than has been reported in other solvent systems. Still higher concentrations may be possible in particular cases by suitable variation in the solvent ratios Procedure 3 (section V) describes such a reduction of estradiol 3-methyl ether at a 0.12 M concentration. A few steriods such as the dimethyl and diethyl ketals of estrone methyl ether are poorly soluble in ammonia-tetrahydrofuran-/-buty] alcohol and cannot be reduced successfully at a concentration of 0.06 even with a 6 hour reduction period. The diethyl ketal of estrone methyl ether is reduced successfully at 0.12 M concentration using a two-phase solvent system of ammonia-/-amyl alcohol-methylcyclohexane (Procedure 4, section V). This mixture probably would be useful for any nonpolar steroid that is poorly soluble in polar solvents but is readily soluble in hydrocarbons. 

To a solution of 1.38 g of estradiol 3-methyl ether (mp 118-119°) in 110 ml of anhydrous ether is added 140 ml of liquid ammonia followed by 1.4 g (42 eq per mole) of lithium wire in small pieces, and 10 min later 16 ml of absolute alcohol is added dropwise over a 10- to 20-min period. Occasionally frothing occurs during the last part of this addition but is easily controlled by stopping the stirrer temporarily. After removing most of the ammonia and carefully adding cold water, the product is extracted with ether, washed with Claisen alkali, water and saturated salt solution, and dried over sodium... 

The general reaction procedure and apparatus used are exactly as described in Procedure 2. Ammonia (465 ml) is distilled into a 2-liter reaction flask and to this is added 165mlofisopropylalcoholandasolutionof30g(0.195 mole) of 17/ -estradiol 3-methyl ether (mp 118.5-120°) in 180 ml of tetrahydrofuran. The steroid is only partially soluble in the mixture. A 5 g portion of sodium (26 g, 1.13 g-atoms total) is added to the stirred mixture and the solid dissolves in the light blue solution within several min. As additional metal is added, the mixture becomes dark blue and a solid (matted needles) separates. Stirring is inefficient for a few minutes until the mass of crystals breaks down. All of the sodium is consumed after 1 hr and 120 ml of methanol is then added to the mixture with care. The product is isolated as in Procedure 4h 2. After being air-dried, the solid weighs 32.5 g (ca. 100% for a monohydrate). A sample of the material is dried for analysis and analyzed as described in Procedure 2 enol ether, 91% unreduced aromatics, 0.3%. The crude product may be crystallized from acetone-water or preferably from hexane. 

Birch reduction of the diethyl ketal of estrone 3-methyl ether in ammonia-methylcyclohexane-t-amyl alcohol,... 

Birch s procedure for tropone synthesis appears to be widely applicable to 2,3- or 2,5-dihydroanisole derivatives which are readily obtained by reduction of appropriate aromatic methyl ethers by alcoholic metal-ammonia solutions. " Additional functional groups reactive to dibromocarbene or sensitive to base such as double bonds, ketones and esters would need to be protected or introduced subsequent to the expansion steps. 

Tlie synthesis concludes by the route pioneered by Eschenmoser. Itromination of 47 proceeds at the position a to the tropolone I ing to give 48. Displacement of halogen by ammonia followed by liase hydrolysis of the tropolone methyl ether gives trimethyl-lolchicinic acid. Acetylation of the amine followed by reesteri-... 

This reaction is similar to 13-1 and, like that one, generally requires activated substrates. With unactivated substrates, side reactions predominate, though aryl methyl ethers have been prepared from unactivated chlorides by treatment with MeO in HMPA. This reaction gives better yields than 13-1 and is used more often. A good solvent is liquid ammonia. The compound NaOMe reacted with o- and p-fluoronitrobenzenes 10 times faster in NH3 at — 70°C than in MeOH. Phase-transfer catalysis has also been used. The reaction of 4-iodotoluene and 3,4-dimethylphenol, in the presence of a copper catalyst and cesium carbonate, gave the diaryl ether (Ar—O—Ar ). Alcohols were coupled with aryl halides in the presence of palladium catalysts to give the Ar—O—R ether. Nickel catalysts have also been used. ... 

The action of diazomethane in aqueous 1,2-dimethoxyethane on 4-methoxy-l-/3-D-ribofuranosyl-2(lf/)-pyrimidinone gave, after purification, the corresponding 2 -methyl ether in 37% yield.333 N.m.r. spectroscopy showed that the crude mono-O-methyl fraction contained the 2 - and 3 - isomers in the ratio of 7 2. The 2 -methyl ether proved to be a versatile intermediate, as acid hydrolysis yielded 2 -0-methyluridine, whereas reaction with ammonia or methylamine... 

Scheme 159) [549, 550]. Temperature and electrolyte concentration are found to have a profound effect on the reaction rate. The Bu4N(Hg) can be used for the reduction of -estradiol 3-methyl ether and the reaction has been shown to be more selective than the conversion methods based on alkali metal-ammonia reduction [551]. 

Tetralone has been prepared by a variety of methods, but the only practical procedures are relatively recent ones involving reduction of /9-naphthyl methyl ether with sodium and alcohol2 or with sodium and liquid ammonia,3 high-pressure catalytic hydrogenation of /9-naphthol,4 or catalytic oxidation of 2-tetralol by hydrogen transfer with ethylene.6... 

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