4-Hydroxycyclopent-2-en-1-one61305-27-9100 % similar 1,4-Cyclohex-2-enedione4505-38-833 % similar 2-Cyclopentene-1,4-dione930-60-933 % similar rac-(1R,4S)-4-Hydroxycyclopent-2-en-1-yl acetate60410-16-431 % similar