By condensation of azacycloheptan-2-one (I) with 1-bromododecane (II) by means of NaH in refluxing toluene.
Coupling of piperazine (I) with chloro derivative (II) by means of K2CO3 and KI in acetone affords protected compound (III), which is then condensed with acid chloride (IV) by means of n-BuLi in THF to yield amide (V). Deprotection of (V) by hydrogenation over Pd/C in EtOH provides (VI), which is finally cyclized by treatment with POCl3 in DMF. Alternatively, the synthesis of the target product can be achieved by an analogous route: Acylation of amine (VII) with acid chloride (IV) by means of K2CO3 in CH2Cl2 provides amide (VIII), which is then cyclized by heating with POCl3 in DMF/benzene to give oxazole (IX). Finally, (IX) is condensed with piperazine (I) by means of K2CO3 and KI in acetone.