Table 3. Screening of Oxidizing Agents for the Conversion of N-Alkylated Isatin to N-Alkylated Isatoic Anhydride for Scheme 3iii.
| entry | oxidizing agents | catalyst | T (°C) | time (h) | yield (%) |
|---|---|---|---|---|---|
| 3A | peracetic acid | 30 | 24 | 70 | |
| 3B | performic acid | 30 | 24 | 75 | |
| 3C | persulfuric acid | 30 | 24 | trace | |
| 4A | hydrogen peroxide | bismuth nitrate | 60 | 48 | nil |
| 4B | hydrogen peroxide | mercuric chloride | 60 | 48 | nil |