4-​Hexenoic acid, 6-​(1,​3-​dihydro-​4-​hydroxy-​6-​methoxy-​7-​methyl-​3-​oxo-​5-​isobenzofuranyl)​-​4-​methyl-​, 2-​(4-​oxido-​4-​morpholinyl)​ethyl ester, (4E)​-