A manufacturing synthesis of 5-chlorophthalide has been elaborated. The key step of the procedure is ortho-lithiation of 4-chloro-N,N-diisopropylbenzamide, followed by formylation with dimethyl formamide. Reduction of the formyl moiety and subsequent ring closure, which can be carried out also in one pot, led to 5-chlorophthalide in high overall yield. The procedure has also been successfully adapted for the synthesis of the 5-fluoro and 5-trifluoromethyl analogues. The compounds thus obtained are useful building blocks in the synthesis of various heterocyclic ring systems.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry