General procedure: Triphenylphosphine (5 mmol) was added to a solution of 4-substituted-benzyl halide (5 mmol) in toluene (50 mL). The mixture was heated to reflux for 6 h and then cooled to room temperature. The precipitate was collected, recrystallized from ethanol to give the products.
General procedure: A mixture of 1.67 g (10.70 mmol) of 1-(chloromethyl)-4-methoxybenzene, 3.35 g (12.8 mmol) of triphenylphosphine, and 11 mL of ethyl acetate was stirred and refluxed for 24 hours and the salt, (4-methoxybenzyl)triphenylphosphonium chloride, was gradually formed and then collected and dried by suction filtration after cooling down.
(a) [(4-Chlorophenyl)methyl]triphenylphosphonium chloride A stirred solution of 158 g, (0.6 mole) of triphenylphosphine in 800 ml of xylene is treated with 97 g of 4-chlorobenzyl chloride. The resulting solution is heated (product begins to crystallize at this point) and refluxed for six hours. After standing overnight at room temperature, the solid is filtered, washed with xylene and then with ethyl acetate, and dried in a desiccator to yield 161 g of colorless solid [(4-chlorophenyl)methyl]triphenylphosphonium chloride; m.p. 283-285.
(a) [(4-Chlorophenyl)methyl]triphenylphosphonium chloride Triphenylphosphine (158 g., 0.60 mole) and 97 g. of 4-chlorobenzyl chloride are reacted in 800 ml. of boiling xylene according to the procedure of Example 25 (a) to yield 161 g. of colorless solid [(4-chlorophenyl)methyl]triphenylphosphonium chloride; m.p. 283-285.
[ 1530-39-8 ]
[ 253778-43-7 ]
dimethyl 8-(tert-butyl)-6-[(E)-2-(4-chlorophenyl)ethenyl]-1,10-dimethylheptalene-4,5-dicarboxylate[ No CAS ]
With sodium hydride; In N,N-dimethyl-formamide; at 0℃; for 0.5h;
Step 1 : 4-bromo-2-[2-(4-chlorophenyl)vinyl]thiophene; To a solution of <strong>[1530-39-8](4-chlorobenzyl)triphenylphosphonium chloride</strong> (17.3g) in DMF (200 mL) at 0 0C, was added NaH (60 % in oil, 2g). The mixture was stirred at 0 C for 30 minutes, after which a solution of 4-bromothiophene-2-carbaldehyde (8 g) in DMF (20 mL) was added. The mixture was stirred at 0 0C for 30 minutes, then warmed up to room temperature and stirred 1 hr. The reaction mixture was quenched by the addition of 1 N HCl and Et20. The aqueous layer was extracted with Et2O, the combined organic layers were washed with brine, dried over Na2SO4 and filtered. The volatiles were removed under reduced pressure and the residue was purified by flash chromatography on silica (100 % hexanes) to afford 4-bromo-2-[2-(4- chlorophenyl)vinyl]thiophene (10 g) as a mixture of isomers.