The alpha-Angelica lactone, with the CAS registry number 591-12-8, is also known as 4-Hydroxypent-3-enoic acid lactone. It belongs to the product category of Miscellaneous Natural Products. Its EINECS number is 209-701-8. This chemical's molecular formula is C₅H₆O₂ and molecular weight is 98.10. What's more, its systematic name is 5-Methyl-2(3H)-furanone. This chemical should be sealed and stored in a cool and dry place. Moreover, it should be protected from oxides. It is commonly used in daily cosmetics and soap essences such as violets, chypret, sunflower and orchid. When using it, you must avoid contact with eyes. 

Physical properties of alpha-Angelica lactone are: (1)ACD/LogP: 0.236; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 0.24; (4)ACD/LogD (pH 7.4): 0.24; (5)ACD/BCF (pH 5.5): 1.00; (6)ACD/BCF (pH 7.4): 1.00; (7)ACD/KOC (pH 5.5): 32.01; (8)ACD/KOC (pH 7.4): 32.01; (9)#H bond acceptors: 2; (10)#H bond donors: 0; (11)#Freely Rotating Bonds: 0; (12)Polar Surface Area: 26.3 Å²; (13)Index of Refraction: 1.472; (14)Molar Refractivity: 24.49 cm³; (15)Molar Volume: 87.535 cm³; (16)Polarizability: 9.709×10^-24cm³; (17)Surface Tension: 33.12 dyne/cm; (18)Density: 1.121 g/cm³; (19)Flash Point: 68.333 °C; (20)Enthalpy of Vaporization: 48.664 kJ/mol; (21)Boiling Point: 249.412 °C at 760 mmHg; (22)Vapour Pressure: 0.023 mmHg at 25°C.

Preparation of alpha-Angelica lactone: this chemical can be prepared by 4-oxo-pentanoic acid. The yield is about 55%.

Uses of alpha-Angelica lactone: it can be used to produce 4-acetyl-5-t-butyl-2(5H)-furanone at the temperature of 50 °C. It will need reagents PdCl₂(PhCN)₂/SnCl₂, Zn and solvent acetonitrile with the reaction time of 32 hours. The yield is about 57%.

You can still convert the following datas into molecular structure:
(1)SMILES: O=C1O\C(=C/C1)C
(2)Std. InChI: InChI=1S/C5H6O2/c1-4-2-3-5(6)7-4/h2H,3H2,1H3
(3)Std. InChIKey: QOTQFLOTGBBMEX-UHFFFAOYSA-N

The toxicity data is as follows: