| 摘要 |
<p>A process is disclosed for nitrating photocleavable compounds comprising a photocleavable group linked to an effector moiety which are capable of releasing the effector moiety on irradiation with light or a group is capable of linkage to an effector moiety. The process employs copper (II) nitrate and acetic anhydride to nitrate substituted indolines at the 7-position. This reaction which proceeds in good yield and selectivity and can be carried out in the presence of the functional groups at the 4-position and/or the effector moiety which is typically linked via an acyl linkage to the heterocyclic nitrogen at the 1-position. These nitration conditions have the advantages of a favourable isomeric ratio of products and leaving the protecting groups intact, thereby giving additional scope for isomer separation. In a preferred embodiment, the present invention employs clay supported copper (II) nitrate ("claycop") and acetic anhydride which provides improved yield and isomeric ratio as compared to the use of homogeneous, soluble copper (II) nitrate.</p> |
