2-Oxo-3-pentene 3-01-00-02985 (Beilstein Handbook Reference) 3-PENTEN-2-ONE 625-33-2 AI3-37794 BRN 1633505 EINECS 210-888-3 Ethylidene acetone FEMA No. 3417 Methyl 1-propenyl ketone Methyl propenyl ketone NSC 61468