4, 9 - epoxy, 3 - (2 - hydroxy - 2 - methyl butyrate) 15 - (S) 2 - methyl butyrate), [3 beta (S), 4 alpha, 7 alpha, 15 alpha ®, 16 beta] - Mr Wen - 3,4,7,14,15,16,20 - heptanol