The reaction of Ro 31-7453 (I) (see scheme no. 28721501a) with formaldehyde in water at 125 C gives the N-hydroxymethyl derivative (II), which is esterified with 2-(polyoxyethylenoxy)acetic acid (III) by means of EDC and DMAP in dichloromethane to yield the target prodrug. Alternatively, the target prodrug can also be obtained by condensation of Ro 31-7453 (I) with 2-(polyoxyethylenoxy)acetic acid chloromethyl ester (IV) by means of Cs2CO3 in DMF.