One-pot synthesis of novel thioxanthone crown ethers

The reaction of thiosalicylic acid (TSA) and benzocrown ethers in concentrated sulfuric acid affords a general and efficient way to prepare thioxanthone crown ethers. This chemistry presumably proceeds by intermolecular sulfur electrophilic reaction and subsequently intramolecular electrophilic cyclization. Most of the reactions show high regioselectivity in good yields.