The cyclization of methyl 2-aminobenzoate (I) with 2,5-dimethoxytetrahydrofuran (II) in refluxing acetic acid gives methyl 2-(pyrrol-1-yl)benzoate (III), which by reduction with LiAlH4 in ether is converted into 2-(pyrrol-1-yl)benzyl alcohol (IV). The cyclization of (IV) with ethyl 2-oxopropionate (V) by means of butyllithium and tetramethylethylenediamine (TMEDA) in THF affords 4-methyl-4H,6H-pyrrolo[1,2-a][4,1]benzoxazepine-4-carboxylic acid ethyl ester (VI), which is hydrolyzed with NaOH in refluxing ethanol to the corresponding free acid (VII). The condensation of (VII) with 1-(piperidin-4-yl)-2,3-dihydro-1H-benzimidazol-2-one (VIII) by means of carbonyldiimidazol (CDI) in THF gives 1-[1-(4-methyl-4H,6H-pyrrolo[1,2-a][4,1]benzoxazepin-4-ylcarbonyl) piperidin-4-yl]-2,3-dihydro-1H-benzimidazol-2-one (IX), which is finally reduced with LiAlH4 in THF, and treated with maleic acid in acetone.

The cyclization of methyl 2-aminobenzoate (I) with 2,5-dimethoxytetrahydrofuran (II) in refluxing acetic acid gives methyl 2-(pyrrol-1-yl)benzoate (III), which by reduction with LiAlH4 in ether is converted into 2-(pyrrol-1-yl)benzyl alcohol (IV). The cyclization of (IV) with ethyl 2-oxopropionate (V) by means of butyllithium and tetramethylethylenediamine (TMEDA) in THF affords 4-methyl-4H,6H-pyrrolo[1,2-a][4,1]benzoxazepine-4-carboxylic acid ethyl ester (VI), which is hydrolyzed with NaOH in refluxing ethanol to the corresponding free acid (VII). The condensation of (VII) with 1-(piperidin-4-yl)-2,3-dihydro-1H-benzimidazol-2-one (VIII) by means of carbonyldiimidazol (CDI) in THF gives 1-[1-(4-methyl-4H,6H-pyrrolo[1,2-a][4,1]benzoxazepin-4-ylcarbonyl) piperidin-4-yl]-2,3-dihydro-1H-benzimidazol-2-one (IX), which is finally reduced with LiAlH4 in THF, and treated with maleic acid in acetone.