8H-7.10-Methanocyclopropa[18.19][1.10.3.6]dioxadiazacyclononadecino[11.12-b]quinoxaline-8-carboxylic acid. 5-(1.1-diMethylethyl)-1.1a.3.4.5.6.9.10.18.19.20.21.22.22a-tetradecahydro-14-Methoxy-3.6-dioxo-. Methyl ester. (1aR.5S.8S.10R.22aR)-