Three‐Component Synthesis of 2‐Substituted Thiobenzoazoles Using Tetramethyl Thiuram Monosulfide (TMTM) as Thiocarbonyl Surrogate

A metal-free synthesis of 2-benzyl/allyl-substituted thiobenzoazoles was developed starting from tetramethyl thiuram monosulfide (TMTM) which served as thiocarbonyl surrogate. By using 2-aminophenols (or 2-aminothiophenols, or 1,2-phenylenediamines) and TMTM as starting materials, 2-mercaptobenzoazoles could be synthesized efficiently. The subsequent C-S bond formation with benzyl/allyl halides gave the final products (2-benzyl/allyl-substituted thiobenzoazoles) with good to excellent yields. The metal-free conditions, inexpensive and easily available starting materials, and broad substrate scope are the advantageous features of this protocol.