The reaction of 1,3-dibromopropane (I) with triethyl phosphite (II) at 160 C gives triethyl 3-bromopropylphosphonate (III), which is treated with Tms-Br and water to yield the corresponding phosphonic acid (IV). The reaction of (IV) with PCl3 in refluxing chloroform affords the acyl chloride (V), which is treated with 4-methoxyphenol (VI) and pyridine to provide the expected 4-methoxyphenyl diester (VII). The reaction of (VII) with N,O-bis(tert-butoxycarbonyl)hydroxylamine (VIII) by means of NaH in DMF gives the fully protected hydroxyamino derivative (IX), which by treatment with TFA in dichloromethane yields 3-(hydroxyamino)propylphosphonic acid 4-methoxyphenyl diester (X). Finally, this compound is acylated with Ac-Cl and TEA in ethyl ether to afford the target N-acetylhydroxyamino compound.