3-Chlorofuran-2(5H)-one is a highly reactive α,β-unsaturated lactone and versatile heterocyclic building block. It serves as a key intermediate in organic synthesis for constructing pyridazinones, aminofuranones, and fused-ring systems via nucleophilic addition/ring-opening/cyclization cascades. Widely used in pharmaceutical synthesis for antimicrobial, anti-inflammatory, and anticancer drug development. Applied in natural product chemistry to synthesize furanone derivatives with diverse biological activities. Used in Diels-Alder reactions to build complex polycyclic lactone systems. Also acts as a raw material for dyestuff and functional material synthesis.

Irritant and reactive. Inhalation of vapor irritates respiratory tract; use ventilation and respirator. Skin contact may cause irritation; wear gloves and wash skin promptly. Eye contact causes severe irritation; flush with water for 15+ minutes. Avoid contact with strong bases, amines, and alcohols (reacts vigorously). Store away from food and oxidants. Dispose as hazardous waste to prevent environmental harm.