Ene ethyl

To a mixture of ethyl 5a-cholestan-3-one 2a-xanthate (2 g, 3.95 mmol) and 100 ml methanol is added sufficient ether to completely dissolve the solids. Sodium borohydride (90 mg, 2.36 mmol) is added directly to the reaction flask and the solution is stirred at room temperature for 4 hr. (The use of an excess of sodium borohydride and an extended reaction time produces 5oc-cholestan-2a,3a-thiirane.) The reaction is diluted with 200 ml ether and washed several times with ca. 100 ml water, dried (MgS04) and the solvent is removed under vacuum. The crude sticky gum is chromatographed on a column of 85 g silicic acid. The hexane eluates contain 5a-cholest-2-ene. Ethyl 5a-cholestan-3a-ol 2a-xanthate is obtained in ca. 30% yield by subsequent elution with benzene hexane (1 7) and the desired ethyl 5a-cholestan-3 -ol 2a-xanthate is eluted with ether hexane (1 3) in ca. 30% yield. 

Step A Ortho-Trif/uoromethy/anilinomethy/ene Ethyl Malonate - A mixture of 54.8 grams of ortho-trifluoromethylaniline and 73.5 grams of ethoxymethylene ethyl malonate was heated to 120°C under an inert atmosphere and maintained for 1 hour at this temperature while distilling off the ethanol formed. The mixture was cooled and the elimination of ethanol was completed by distillation under reduced pressure. The mixture was cooled to obtain 115 grams of ortho-trifluoromethylanilinomethylene ethyl malonate which was used as is for the following stage. A sample of the product was crystallized from petroleum ether (8P = 65° to 75°C) to obtain a melting point of 94°C. 

The first examples of ortho cycloaddition can be found in a U.S. patent of Ayer and Buchi [1], Benzonitrile and 2-methylbut-2-ene are reported to yield 7,8,8-trimethylbicyclo[4.2.0]octa-2,4-diene-l-carbonitrile upon irradiation under nitrogen with a mercury resonance arc. Similar reactions, all leading to derivatives of bicyclo[4.2.0]octa-2,4-diene-l-carbonitrile occurred when benzonitrile was irradiated in the presence of 2,4,4-trimethylpent-l-ene, ethyl vinyl ether, vinyl acetate, methyl vinyl ketone, and methyl acrylate. The addend pairs para-tolunitrile/oct-l-ene, ort/m-dicyanobenzene/2-methylbut-2-ene, para-dicyanobenzene/but-l-ene, 2,3-dimethylbenzonitrile/propene, and 3,4,5-trimethylbenzonitrile/ethene likewise produced ortho photocycloadducts. 

S,4-Dideoxy-o- glycero-Aeiosu/os- S-ene Ethyl acetate satd. voith water Bvtanone satd. with water 1-Butanol satd. with water Color ... 

Preparation of Bicyclo[2.2.1]hept-2-ene—Ethyl Acrylate-Sulfur Dioxide Terpolymer [61]... 

Iron. Alk-l-enes, ethyl acrylate, ethyl crotonate, ethyl but-3-enoate, and styrene are all carbonylated by carbon monoxide in the presence of K[FeH(CO)4] or K2[Fe(CO)4]. Vinylcyclopropanes (103) are carbonylated in the presence of Fe(CO)5 or FcaCCO), under irradiation. The initial product is (104), which can isomerize to (105). The reaction of alkenes... 

Pfrang, C., C. Tooze, A. Nalty, C.E. Canosa-Mas, and R.P. Wayne (2006b), Reactions of NO3 with the man-made emissions 2-methylpent-2-ene, (Z)-3-methylpent-2-ene, ethyl vinyl... 

Formula M.p. Methyl ester M.p. Ethyl ester M.p. Acetyl deriv M.p. Benzoyl deriv M.p 3.5 Dinitro. benzoyl deriv. M.p. Naphthal- ene sulphonyl deriv. M.p. 

FIGURE 13 16 The methyl ene protons of ethyl bro mide split the signal of the methyl protons into a triplet... 

Methyl- and dimethylnaphthalenes are contained in coke-oven tar and in certain petroleum fractions in significant amounts. A typical high temperature coke-oven coal tar, for example, contains ca 3 wt % of combined methyl- and dimethylnaphthalenes (6). In the United States, separation of individual isomers is seldom attempted instead a methylnaphtha1 ene-rich fraction is produced for commercial purposes. Such mixtures are used for solvents for pesticides, sulfur, and various aromatic compounds. They also can be used as low freezing, stable heat-transfer fluids. Mixtures that are rich in monomethyinaphthalene content have been used as dye carriers (qv) for color intensification in the dyeing of synthetic fibers, eg, polyester. They also are used as the feedstock to make naphthalene in dealkylation processes. PhthaUc anhydride also can be made from m ethyl n aph th al en e mixtures by an oxidation process that is similar to that used for naphthalene. 

The crude ketal from the Birch reduction is dissolved in a mixture of 700 ml ethyl acetate, 1260 ml absolute ethanol and 31.5 ml water. To this solution is added 198 ml of 0.01 Mp-toluenesulfonic acid in absolute ethanol. (Methanol cannot be substituted for the ethanol nor can denatured ethanol containing methanol be used. In the presence of methanol, the diethyl ketal forms the mixed methyl ethyl ketal at C-17 and this mixed ketal hydrolyzes at a much slower rate than does the diethyl ketal.) The mixture is stirred at room temperature under nitrogen for 10 min and 56 ml of 10% potassium bicarbonate solution is added to neutralize the toluenesulfonic acid. The organic solvents are removed in a rotary vacuum evaporator and water is added as the organic solvents distill. When all of the organic solvents have been distilled, the granular precipitate of 1,4-dihydroestrone 3- methyl ether is collected on a filter and washed well with cold water. The solid is sucked dry and is dissolved in 800 ml of methyl ethyl ketone. To this solution is added 1600 ml of 1 1 methanol-water mixture and the resulting mixture is cooled in an ice bath for 1 hr. The solid is collected, rinsed with cold methanol-water (1 1), air-dried, and finally dried in a vacuum oven at 60° yield, 71.5 g (81 % based on estrone methyl ether actually carried into the Birch reduction as the ketal) mp 139-141°, reported mp 141-141.5°. The material has an enol ether assay of 99%, a residual aromatics content of 0.6% and a 19-norandrost-5(10)-ene-3,17-dione content of 0.5% (from hydrolysis of the 3-enol ether). It contains less than 0.1 % of 17-ol and only a trace of ketal formed by addition of ethanol to the 3-enol ether. 

Androst-4-ene-3,l7-dione 3-Ethylene Thioketal A solution of androst-4-ene-3,17-dione (1.42 g, 5 mmoles) in acetic acid (20 ml) is treated with ethanedithiol (0.47 g, 5 mmoles) and a solution of 0.45 of p-toluenesulfonic acid monohydrate in acetic acid (5 ml). After 1 hr at room temperature, the pale yellow solution is poured into water and the resulting suspension is extracted with chloroform. The chloroform solution is washed with water, 5 % sodium hydroxide solution and water, dried (Na2S04) and evaporated. Chromatography of the resulting oil (1.93 g) over silica gel yields androst-4-ene-3,17-dione bisethylene thioketal, mp 173-175° [0.16 g, eluted with petroleum ether-benzene (1 2)] and androst-4-ene-3,17-dione 3-ethylene thioketal, mp 173-176° [1.38 g (76%), eluted with benzene-ethyl acetate (19 1)]. 

Further development of the column with 25% ethyl acetate in benzene produces 2.5 g of material, which on repeated crystallization yields 0.22 g of 17a,21-dihydroxypregn-4-ene-3,ll,20-trione 21-acetate mp 248-251°. Identity with cortisone acetate is established by a comparison of infrared spectra. Elution of the column with 30 % ethyl acetate in benzene gives after crystallization, 0.21 g of ll/9,17a,21-trihydroxypregn-4-ene-3,20-dione 21-acetate mp 219-222°. 

The photolytic and thermolytic decomposition of azides in the presence of olefins has been applied to aziridine synthesis. However, only a limited number of steroid aziridines have been prepared in this manner. The patent literature reports the use of cyanogen azide at ca. 50° for 24 hours in ethyl acetate for the preparation of an A-nor- and a B-norsteroidal aziridine. The addition is believed to proceed via a triazoline. The reaction of cholest-2-ene with ethyl azidoformate takes place in a nonselective manner to produce a mixture of substances, including C—H insertion products. 

A solution of 5 g (14 mmoles) of 5a-cholest-2-ene in 100 ml ethyl acetate and 8 ml of 2.8 M (22 mmoles) cyanogen azide (CAUTION See Chapter 15 and ref. 139b) in ethyl acetate is heated at 50-53° for 24 hr, during which time about 22 mmoles of nitrogen is evolved. Solvent is removed by evaporation and the residue is applied in benzene to a column of 160 g of neutral alumina (activity grade III). Elution with petroleum ether-benzene (1 1) gives 1.6 g of... 

High vacuum sublimation of the 3-monobenzoate of (32) or tosylchloride dehydration gives 3/ -benzoyloxy-7-methylenecholest-5-ene (33). The configuration of (32) is probably as shown since 7a-hydroxy steroids dehydrate readily to yield homoannular dienes. In an analogous reaction ethyl and iso-butyl Grignard reagents give alkylidene compounds as the only isolated products. 

The epimeric 17 -methylandrost-5-ene-3, 17a-diol could be isolated as a by-product from larger scale experiments. Reaction of (49) with ethyl-magnesium halide affords the corresponding 17a-ethyl compound. In this... 

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