5713. Maltol

Nomenclature

CAS number: 118-71-8
3-Hydroxy-2-methyl-4H-pyran-4-one; 3-hydroxy-2-methyl-4-pyrone; 3-hydroxy-2-methyl-γ-pyrone; larixinic acid; palatone; veltol.
C6H6O3; mol wt 126.11.
C 57.14%, H 4.80%, O 38.06%.

Description and references

Found in the bark of young larch trees (Larix decidua Mill.), in pine needles (Abies alba Mill., Pinaceae), in chicory, in wood tars and oils, in roasted malt. Isoln from these sources and structure: Kiliani, Bazlen, Ber. 27, 3115 (1894); Feuerstein, Ber. 34, 1804 (1901); Erdmann, Schaefer, Ber. 43, 2398 (1910); Reichstein, Beitter, Ber. 63, 824 (1930), cf. Peratoner, Tamburello, Chem. Zentralbl. 76, II 680 (1905). Also obtained by alkaline hydrolysis of streptomycin salts: Schenck, Spielman, J. Am. Chem. Soc. 67, 2276 (1945). Synthesis: Spielman, Freifelder, ibid. 69, 2908 (1947); Chawla, McGonigal, J. Org. Chem. 39, 3281 (1974). Novel high-yield synthesis: T. M. Brennan et al., Tetrahedron Lett. 1978, 331; P. D. Weeks et al., J. Org. Chem. 45, 1109 (1980). History and comparison with isomaltol: Hodge, Nelson, Cereal Chem. 38, 207 (1961).

Chemical structure

Properties

Monoclinic prisms from chloroform, orthorhombic bipyramidal crystals + monoclinic prisms from 50% alcohol, mp 161-162°. Fragrant, caramel-like odor. Begins to sublime at 93°. Volatile with steam. uv max (0.1N HCl): 274 nm (Em 8400); (0.1N NaOH): 317 nm (Em 7300). pH of 0.5% aq soln 5.3. One gram dissolves in 85 ml water. Freely sol in hot water, chloroform; sol in alcohol; sparingly sol in benzene, ether, petr ether; sol in aq alkali hydroxides giving yellow solns.

Use

Flavoring agent, to impart “freshly baked” odor and flavor to bread and cakes.