Cyclobutanone → 6-[(3-Cyclobutyl-8-Iodo-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yl)oxy]-N-methyl-3-pyridinecarboxamide

N-Methyl-6-(8-iodo-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yloxy)-3-pyridinecarboxamide (D43) (423 mg, 1.0 mmol) was dissolved in 2.5% acetic acid in methanol (5 ml) and treated dropwise with cyclobutanone (0.11 ml, 1.5 mmol). The mixture was stirred for 30 minutes and then (polystyrylmethyl)trimethylammonium cyanoborohydride (2.0 mmol/g, 1 g, 2 mmol) was added. The reaction mixture was stirred at room temperature for 18 hours, applied to a SCX ion exchange cartridge (Varian bond-elute, 10 g) and washed with methanol and then a mixture of 0.880 ammonia:methanol (1:9). The combined basic fractions were concentrated in vacuo and the resulting residue purified by column chromatography eluting with a mixture of 0.880 ammonia:methanol:dichloromethane (0.5:2.25:97.5) to afford the title compound (E225). MS (ES+) m/e 478 [M+H]+.