the ethylidene side-chain was located at nitrogen atom. The
similar NOESY (Supporting information) and ECD spectro-
scopic data of 2 and 1 (Fig. 4) suggested that their absolute
configurations were identical. Accordingly, the structure of
2 was identified as 5α,2′-dihydroxy-1α,2α-diacetoxycass-
8,11,13(15)-trien-N-ethylidene-16,12-lactam and named
caesalminine B.