Ethylene, bromo

Ethylene, bromo-(8) Ethene, bromo- (9) (593-50-2) Bicyclo[3.2.0]heptan-2-ol, 3,3-dimethyl- (9) (71221-67-5) Bis(copper(I) trif1uoromethanesulfonate)benzene complex Copper,... 

In Sec. 17.10 a mechanism is proposed for the conversion of ethylene bromo-hydrin into ethylene oxide in the presence of base, (a) To what general class does this reaction belong (b) Using models, show the likely steric course of this reaction, (c) Can you suggest a reason why sodium hydroxide readily converts /r<7/i5-2-chlorocyclohexanol into cyclohexene oxide, but converts the c/5-isomer into entirely different products (d) Account for the fact that addition of chlorine and water to oleic acid (c(5-9-octadece-noic acid) followed by treatment with base gives the same epoxide (same stereoisomer) as does treatment of oleic acid with a peroxy acid. 

Lagentoark, Ber., 1874, 7, 912. 2 roino-l-iodoetbane Ethylene bromo-iodide)... 

The bromine adds on at the ethylenic linkage to form thedibromo compound (I), which easily loses hydrogen bromide to give the mono-bromo keto ester (II) ... 

Owing to their particular interest two individual reactions will now be discussed separately. The reaction of methoxycarbonylhydrazine and 3-bromo-2,4-pentanedione affords, in addition to the expected pyrazole (608), a pyrazolium salt (609), the structure of which was established by X-ray crystallography (74TL1987). Aryldiazonium salts have been used instead of arylhydrazines in the synthesis of pyrazolines (610) and pyrazoles (611) (82JOC81). These compounds are formed by free radical decomposition of diazonium salts by titanium(n) chloride in the presence of a,/3-ethylenic ketones. 

Acetoxyandrost-5-en-17-one (59) is converted into the ethylene ketal (60) by treatment with ethylene glycol, triethylorthoformate and p-toluenesulfonic acid. The ketal is brominated with pyridinium bromide perbromide in THF and then treated with sodium iodide to remove bromine from the 5 and 6 positions. This gives the 16a-bromo compound (61) which is hydrolyzed in methanol to the free alcohol (62). Dehydrobromination is effected with potassium Fbutoxide in DMSO to give the -compound (63). Acid catalyzed hydrolysis of the ketal in aqueous acetone gives the title compound (64). ... 

This ionic mechanism is supported by kinetic data. A free radical mechanism has been proposed for the unique bromination (with bromine) of 3a, 12a-diacetoxypregnan-20-one ethylene ketal, which gives the 21-bromo derivative in excellent yield. ... 

Many stilbenelike thiophene compounds have been prepared for a study of estrogenic activity, especially by Buu-Hoi et al. Thiophene derivatives of nonhydroxylated stilbene types showed no significant activitywhereas weak estrogenic activity was found in 5-acetyl-, 5-propionyl-, and 5-benzoyl-2-(-stilbenyl)thiophene. 1-Bromo-l,2-diphenyl-2-(5-bromo-2-thienyl)ethylene (258) was found to inhibit body growth and to produce extensive testicular atropy in male rats. A thiophene analog of estrogenic isoflavones (259)... 

Brom-. of or combined with bromine bromo- (as Brombenzoeadure, bromobenzoic acid) bromide of (as Brombaryum, barium bromide). -ammoD, tn., ammonium, n. ammonium bromide, -antimon, n. antimony bromide, -arsen, n., -arsem k, tn. arsem c bromide. ather, tn. ethyl bromide, -athyl, n. ethyl bromide. athylen, n. ethylene bromide, athyiformin, n. Pharm.) bromalin. -atom, n. bromine atom, -baryum, n. barium bromide. beere, /. blackberry, brombeerrot, a. blackberry ed. 

Ethane, bromo-, 55, 91, 92 Ethane, 1,2-dibromo-, 1,2-ethanediyl bromide [Ethylene bromide], 55, 94... 

Dichlorodibenzo- -dioxin. 2-Bromo-4-chlorophenol (31 grams, 0.15 mole) and solid potassium hydroxide (8.4 grams, 0.13 mole) were dissolved in methanol and evaporated to dryness under reduced pressure. The residue was mixed with 50 ml of bEEE, 0.5 ml of ethylene diacetate, and 200 mg of copper catalyst. The turbid mixture was stirred and heated at 200°C for 15 hours. Cooling produced a thick slurry which was transferred into the 500-ml reservoir of a liquid chromatographic column (1.5 X 25 cm) packed with acetate ion exchange resin (Bio-Rad, AG1-X2, 200-400 mesh). The product was eluted from the column with 3 liters of chloroform. After evaporation, the residue was heated at 170°C/2 mm for 14 hours in a 300-cc Nestor-Faust sublimer. The identity of the sublimed product (14 grams, 74% yield) was confirmed by mass spectrometry and x-ray diffraction. Product purity was estimated at 99- -% by GLC (electron capture detector). 

The use of phenylpiperidinols rather than the meperidine-related piperidines as the basic component in antidiarrheal compounds results in retention of activity. The fact that the base is not directly related to a narcotic presumably leads to greater selectivity of action on the gut. Ring scission of butyrolactone 98 (obtainable by alkylation of a diphenylacetate ester with ethylene oxide) with hydrogen bromide gives the bromo acid 99. This is then converted to the dimethylamide by successive treatment with thionyl chloride and dimethylamine. 

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