The esterification of myricerone (I) with 2-(diethoxyphosphoryl)acetic acid (II) by means of CDI gives the corresponding ester (III), which is condensed with the benzaldehyde (IV) by means of DBU and LiCl in DMF yielding the expected condensation product (V). Finally, this compound is hydrolyzed with LiOH in aqueous DME, and treated with aqueous NaOH to obtain the target sodium salt. The intermediate benzaldehyde (IV) has been obtained as follows: The reduction of 5-hydroxy-2-nitrobenzaldehyde (VI) with TiCl3 gives 2-amino-5-hydroxybenzaldehyde (VII), which is then condensed with maleic acid monomethyl ester monochloride (VIII).
The esterification of myricerone ethyleneketal (IX) with 2-(diethoxyphosphoryl)acetic acid (II) by means of CDI gives the corresponding ester (X), which is condensed with the benzaldehyde (IV) by means of DBU and LiCl in DMF yielding the expected condensation product (XI). The hydrolysis of (XI) with LiOH in aqueous DME affords the free acid (XII), which is treated with HCl in THF/water to eliminate the ketal protecting group providing the target compound as free acid (XII). Finally, this compound is treated with aqueous NaOH to obtain the target sodium salt.