7,8-Dimethoxy-3-(3-iodopropyl)-1,3-dihydro-2H-3-benzazepin-2-one

A mixture of the chloride of formula (Ilia) (50.00 g; 169 mmol) and sodium iodide (32.75 g; 218 mmol) in methyl isobutyl ketone (375 ml) was heated to 117 - 118°C with stirring under an argon atmosphere. Reaction progress was monitored by HPLC. After completion, the reaction mixture was concentrated in vacuo and the residue was diluted with dichloro methane (375 ml) and water (190 ml). The organic layer was separated, washed with water (190 ml) and concentrated in vacuo. The residue was treated with methyl t- butyl ether (190 ml) and the resulting suspension was cooled to 0°C. After 1 hour of stirring at 0°C, the suspension was filtered, washed with methyl i-butyl ether (40 ml) and dried for two hour at 23°C/100 mbar to afford 60.10 g of yellowish solid (92percent yield).A mixture of 7, 8-dimethoxy-3 -[3 -chloropropyl]- 1, 3 -dihydro-2H-3 -benzazepin-2-one (40g) prepared as in Example 1, and acetone (320mL) was stirred for about 10mm and sodium iodide (20g) was added to it. The reaction mixture was stirred at about reflux temperature for about 24h. The reaction mixture was cooled to about room temperature, filtered and washed with acetone. The filtrate obtained was concentrated under reducedpressure to give a solid residue. The residue obtained was dissolved in dichioromethane (400rnL). The solution obtained was washed with aqueous sodium dithionate solution and demineralized water and was concentrated under reduce pressure. The solid obtained was recrystallized with acetone and then with acetonitrile and dried under vacuum.Yield: 44.5g (85percent); HPLC purity: > 95percent