The condensation of diethyl acetamidomalonate (I) with ethyl 7-bromoheptanoate (II) by means of sodium ethoxide in refluxing ethanol gives diethyl acetamido-(6-ethoxycarbonylhexyl)malonate (III), which is hydrolyzed and decarboxylated with refluxing concentrated HCl yielding 2-aminononanedioic acid (IV). This acid is esterified with SOCl2 and ethanol to the corresponding diethyl ester (V), which is condensed with vinyl cyclohexyl ketone (VI) to afford diethyl 2-[(3-oxo-3-cyclohexylpropyl)amino]nonanedioate (VII). The reaction of (VII) with potassium cyanate in ethanol-HCl gives the corresponding hydantoic ester (VIII), which is cyclized by heating at 100 C affording 5-(6-carboxyhexyl)-1-(3-cyclohexyl-3-oxopropyl)hydantoin (IX). Finally, this compound is reduced with NaBH4 in ethanol.