2052-15-5 4-03-00-01563 (Beilstein Handbook Reference) 4-Ketopentanoic acid butyl ester AI3-00518 BRN 1768453 Butyl 4-ketovalerate Butyl 4-oxopentanoate Butyl acetylpropionate Butyl laevulinate Butyl levulinate EINECS 218-143-4 FEMA No. 2207 LEVULINIC ACID, BUTYL ESTER NSC 78451 Pentanoic acid, 4-oxo-, butyl ester n-Butyl 4-oxopentanoate n-Butyl laevulinate n-Butyl levulinate