4'-(Dibromomethyl)-[1,1'-Biphenyl]-2-Carbonitrile

114772-53-1

209911-63-7

114772-54-2

The general procedure for the synthesis of 4-(dibromomethyl)-[1,1-biphenyl]-2-carbonitrile and 4'-(bromomethyl)-[1,1'-biphenyl]-2-carbonitrile from 2-cyano-4'-methylbiphenyl was as follows: firstly, 23 g of 2-(4-methylphenyl)benzylcarbonitrile (MPB), 22 g of N-bromosuccinimide (NBS) and 47 mg of 2,2'-azobis(2,4 -dimethylpentanenitrile) were suspended in 44 ml of dichloromethane and the reaction was stirred at 45 to 50 °C for 5 hours. After completion of the reaction, 46 ml of water was added and the organic layer was separated (this process was repeated three times). The organic layers were combined and concentrated, followed by the addition of 50 ml of acetonitrile. The solution was concentrated again and 50 ml of acetonitrile was added to give 116 g of 2-(4-bromomethylphenyl)benzyl cyanide (BMB) in acetonitrile solution (84% yield). Next, 30.1 g of methyl 2-tert-butoxycarbonylamino-3-nitrobenzoate (BAN), 40.8 g of potassium carbonate and 160 ml of acetonitrile were added to the above acetonitrile solution, and the reaction mixture, which may contain unreacted MPB and 2-(4,4-dibromomethylphenyl) benzylnitrile as an analog of BMB, was stirred for about 5 hr at about 82 °C. After cooling to room temperature, the precipitated crystals were collected by filtration and the filtrate was concentrated to give methyl 2-[N-tert-butoxycarbonyl-N-[(2'-cyanobiphenyl-4-yl)methyl]amino]-3-nitrobenzoate (BBN). The concentrate was dissolved in 190 g of methanol, 106 g of concentrated hydrochloric acid was added dropwise, heated to reflux temperature and stirred for 2 hours. After cooling, the precipitated crystals were collected by filtration and dropwise addition to give 35.1 g of methyl 2-[N-(2'-cyanobiphenyl-4-yl)methylamino]-3-nitrobenzoate (MBN) (76.1% yield relative to MPB). Reference Example 4 (1) describes the synthesis of BMB: 271 kg of MPB, 256 kg of NBS, 543 kg of 2,2'-azobis(2,4-dimethylpentanenitrile) (ABN-V), and 680 kg of dichloromethane were stirred at reflux at 45 to 50°C until the percent area of BMB exceeded 82% as determined by HPLC (about 2 to 5 hours). The reaction solution was cooled to 38 to 42°C, 250 kg of dichloromethane and 540 L of water were added, the organic layer was separated and extracted with an aqueous layer (repeated three times). Concentrate the dichloromethane layer to ~700L (~2.5 times MPB volume), add ~640kg acetonitrile and maintain internal temperature 45-55°C (ideally 45-50°C) under reduced pressure (~200-450 mmHg). About 480kg of acetonitrile was added and concentrated to about 500L under reduced pressure, maintaining the same temperature. Finally, about 480 kg of acetonitrile was added to make a solution volume of about 1100 L to obtain an acetonitrile solution containing BMB, unreacted MPB and 2-(4,4-dibromomethylphenyl)benzyl cyanide as a BMB analog.