Tetrahydro-2-isocyanato-2H-pyran is a heterocyclic compound featuring a six-membered tetrahydropyran ring with an isocyanate (-N=C=O) functional group attached. It is a colorless to pale yellow liquid with a characteristic pungent odor and is moisture-sensitive, reacting readily with water, alcohols, and amines. This compound is primarily utilized as a key monomer and crosslinking agent in polymer chemistry. Its main application is in the synthesis of polyurethane resins, coatings, and adhesives. The isocyanate group reacts with polyols to form urethane linkages, which are the fundamental building blocks of polyurethane materials. The tetrahydropyran ring structure can impart specific properties to the resulting polymers, such as improved flexibility, chemical resistance, or adhesion characteristics. Due to its reactivity, it is also employed in organic synthesis as a versatile building block for introducing the tetrahydropyranyl-isocyanate moiety into more complex molecules. Handling requires strict precautions as isocyanates are respiratory and skin sensitizers. It must be stored under inert atmosphere and protected from moisture to prevent polymerization or decomposition.