647. Angelica Lactone

Nomenclature

CAS number: 1333-38-6
5-Methyl-2-furanone.
C5H6O2; mol wt 98.10.
C 61.22%, H 6.16%, O 32.62%.

Description and references

Exists in three forms. Prepn of α and β-forms: Wolff, Ann. 229, 250 (1885); Thiele, Ann. 319, 184 (1901); v. Auwers, Ber. 56, 1672 (1923); J. H. Helberger et al., Ann. 561, 215 (1949). Prepn of α′-form: J. P. Wineburg et al., J. Heterocycl. Chem. 12, 749 (1975); V. Jger, H. J. Günther, Tetrahedron Lett. 1977, 2543; R.A. Amos, J. A. Katzenellenbogen, J. Org. Chem. 43, 560 (1978). Toxicity data for α-form: E. J. Moran et al., Drug Chem. Toxicol. 3, 249 (1980).

Chemical structure

Derivative

α-Form.

Nomenclature

5-Methyl-2(3H)-furanone; Δ2-angelica lactone; γ-methyl-β,γ-crotonolactone; 4-hydroxy-3-pentenoic acid γ-lactone.

Properties

Volatile needles, mp 18°. d420 1.084. bp12 56°. nHe20 1.4476. One gram dissolves in 20 ml water at 15°. Heating with triethylamine soln converts it to the β-form. LD50 orally in mice: 2800 mg/kg (Moran).

Derivative

β-Form.

Nomenclature

5-Methyl-2(5H)-furanone; Δ1-angelica lactone; γ-methyl-α,β-crotonolactone; 4-hydroxy-2-pentenoic acid γ-lactone.

Properties

Liquid. Not solidified at 17°. d420 1.076. bp751 208-209°. bp10 87°. nHe20 1.4603. Sol in water. Forms a dimer. More stable than α-form.

Derivative

α′-Form.

Nomenclature

Dihydro-5-methylene-2(3H)-furanone; γ-methylene-γ-butyrolactone.

Properties

bp17 80°.