Synthesis of phosphoric esters

Process for the preparation of a compound of the formula Id

• where R4 stands for a straight-chain or branched alkyl having 1-20 C atoms, a straight-chain or branched alkenyl having 2-20 C atoms and one or more double bonds, a straight-chain or branched alkynyl having 2-20 C atoms and one or more triple bonds, or a saturated, partially or fully unsaturated cycloalkyl having 3-24 C atoms optionally substituted by alkyl groups having 1-6 C atoms,
• where R4 is optionally substituted by —OR1, —NR12, —CN, —C(O)NR12, —COOR1, —C(═O)R1, —SO2NR12 or aromatic groups, which are optionally provided with conventional protecting groups and in which one or more C atoms are optionally replaced by heteroatoms, where R1 stands for H, C1- to C6-alkyl, C3- to C7-cycloalkyl, or unsubstituted or substituted phenyl, and
• R5 stands, independently of R4, for a straight-chain or branched alkyl having 1-20 C atoms, a straight-chain or branched alkenyl having 2-20 C atoms and one or more double bonds, a straight-chain or branched alkynyl having 2-20 C atoms and one or more triple bonds, or a saturated, partially or fully unsaturated cycloalkyl having 3-24 C atoms optionally substituted by alkyl groups having 1-6 C atoms, where R5 is optionally substituted by —OR1, —NR12, —CN, —C(O)NR12, —COOR1, —C(═O)R1, —SO2NR12 or aromatic groups, which are optionally provided with conventional protecting groups and in which one or more C atoms are optionally replaced by heteroatoms, where R1 stands for H, C1- to C6-alkyl, C3- to C7-cycloalkyl or un-substituted or substituted phenyl,
• characterised in that, in a first step, phosphorus oxychloride is reacted with an N-containing heteroaromatic compound, in subsequent steps, the resulting heteroaromatic compounds are partially substituted by compounds having OH functions to provide the OR4 and OR5 groups, provided that the resulting compound contains one group of the formula II:
• and in a final step the compound Id is prepared by hydrolysing the
• group at pH≧7, where (—X—Y—) stands for
• —CH—CH—CH—,
• —Z—CH—CH—,
• —CH—Z—CH—,
• —CH—CH—Z—,
• —CH—Z—,
• —Z—CH— or
• —Z—Z—,
• where Z is in each case selected, independently of one another, from the group O, S, N, or NH so as to give an aromatic system.