Efficient Synthetic Route to Carbopyronine Fluorenscent Dye Intermediate

摘要

An efficient synthesis of 2,7-bis(dimethylamino)-9,10-dihydro-9,9-dimethylanthracene via a non-protic Lewis acid assisted cyclization reaction in a high yield was described. The key step was a Lewis acid assisted cyclization reaction. Several non-protic Lewis acids were investigated and the optimal condition of cyclization reaction was determined to be 2.5 equiv, of Lewis acid at 0 ℃ for 6 h and at room temperature for 10 h.