4-?Methyl-?benzenesulfonic Acid (2E)?-?[(5R)?-?2-?Methyl-?5-?(1-?methylethenyl)?-?2-?cyclohexen-?1-?ylidene]?hydrazide-d4 is an intermediate in synthesizing (+)-Limonene-d5 (L461742). It is present in blood oranges which show inhibition of angiogenesis in human colon cancer cells. Extracted from the oils of Mentha spicata it shows antimicrobial activity.