1.3- Dibromo-l-phenylpropane

Phenylcyclopropane has been prepared by the base catalyzed decomposition of 5-phenylpyrazoline (33 %),2 by the reaction of 1,3-dibromo-l phenylpropane with magnesium (68%),3 and by the reaction of 3-phenylpropyltrimethylammomum iodide with sodium amide in liquid ammonia (80%)4 However, the method frequently used at present is the reaction of styrene with the methylene iodide-zinc reagent (32%)5... 

BtURET, 1-PHENYL-2-THIO-, 42,87 Bromination, of 2-aminopyridine, 44,34 of l-bromo-3-phenylpropane with N-bromosuccinimide to give 1,3-dibromo-l-phenylpropane,... 

B. Cydopropylbenzene. In a 1-1. three-necked flask equipped, with a stirrer and a thermometer extending into the flask but free from the stirrer are placed 500 ml. of redistilled dimethyl-formamide and zinc-copper couple prepared from 131 g. (2 g. atoms) of zinc (Note 8). The mixture is cooled to 7° in an ice bath, and 1,3-dibromo-l-phenylpropane is added to the stirred mixture at a rate sufficient to maintain the reaction temperature at 7-9° (Note 9). The mixture is stirred for 30 minutes after the addition is completed, poured into 1 1. of water, and then steam-distilled until the condensate is homogeneous or 11. of water has been collected. The organic layer is separated from the distillate, and the aqueous layer is extracted with three 100-ml. portions of ether. The combined organic portions are washed with four 50-ml. portions of water and dried over anhydrous potassium carbonate. The ether is removed by distillation at atmospheric pressure at water bath temperature. The residue is distilled to give 88-100 g. (75-85%) of cydopropylbenzene, b.p. 170-175° (Note 10), 26d 1.5306-1.5318. 

Dibromo-l-phenylpropane added with ice-cooling to a stirred mixture of zinc-copper couple and dimethylformamide at such a rate as to keep the temp, at 7-9°, stirring continued 30 min. cyclopropylbenzene. Y 75-85%. T. F. Corbin, R. G. Hahn, and H. Shechter, Org. Synth. 44, 30 (1964). 

Dehydrobromination of 2,3-dibromo-l,l,l-trifluoro-3-phenylpropane (30) and 2-bromo-3,3,3-trifluoro-l-phenylprop-l-ene (31) leads to 3,3,3-trifluoro-1-phenylprop-1-yne (32).62... 

A suspension of 2,3-dibromo-l-(4-nitrophenyl)-3-phenylpropan-l-one 1 (5 g, 12.2 mmol) in 50 ml of 95% ethanol and 12-15 ml of concentrated ammonium hydroxide was stirred for 6.5 h and filtered (Scheme A.3). nms-2-Phenyl-3-(4-nitrobenzoyl)aziridine 2 was recrystallized from ethanol. Melting point 122-122.5°C. 

Debromination. Benzylic bromination of 3-bromo-l-phenylpropane gives the 1,3-dibromo derivative in nearly 100% yield. A mixture of 500 ml. of dimethyl-formamide and 2 g. atoms of zinc copper couple (method 2) is stirred at 7° and the... 

Free-radical bromination of l-methyl-2-phenylcyclopropane (4) at — 78 °C followed by reduction of the products yields butylbenzene (5) and small amounts of 2-methyl- (6) and/or 1-methyl-1-phenylpropane (7). The light-induced addition of bromine to cis- and tranj-1,2-diphenyl-cyclopropane gave l,3-dibromo-l,2-diphenylpropane exclusively. The monophenyl deriva-... 

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