The chlorination of 8-acetamido-2,3-dihydro-1,4-benzodioxin-5-carboxylic acid (I) with chlorine in acetic acid gives the 7-chloro derivative (II), which is treated with aqueous NaOH to yield 8-amino-2,3-dihydro-1,4-benzodioxin-5-carboxylic acid (III). The reaction of (III) with carbonyldiimidazole (CDI) affords the activated intermediate (IV), which is finally condensed with 1-(1-butylpiperidin-4-yl)methanol (V) by means of MeLi in THF. The intermediate 1-(1-butylpiperidin-4-yl)methanol (V) has been obtained by condensation of piperidine-4-carboxylic acid ethyl ester (VI) with 1-bromobutane (VII) by means of K2CO3 in methanol, followed by reduction of the ester group with LiAlH4 in THF.

The chlorination of 8-acetamido-2,3-dihydro-1,4-benzodioxin-5-carboxylic acid (I) with chlorine in acetic acid gives the 7-chloro derivative (II), which is treated with aqueous NaOH to yield 8-amino-2,3-dihydro-1,4-benzodioxin-5-carboxylic acid (III). The reaction of (III) with carbonyldiimidazole (CDI) affords the activated intermediate (IV), which is finally condensed with 1-(1-butylpiperidin-4-yl)methanol (V) by means of MeLi in THF. The intermediate 1-(1-butylpiperidin-4-yl)methanol (V) has been obtained by condensation of piperidine-4-carboxylic acid ethyl ester (VI) with 1-bromobutane (VII) by means of K2CO3 in methanol, followed by reduction of the ester group with LiAlH4 in THF.