Constituents of commercial Brazilian lantana oil

The constituents of the commercial Brazilian lantana oil are mainly bisabol ene derivatives, altogether about 65%. The following new natural compounds were characterized by their H-1-NMR and partly C-13-NMR data: 1,12-epoxycad ina-3,11-dienes (37, 40), helifolen-15-als (38/39), acora-2,4(15)-dien-11-o l (44), (E)-sesquithujen-12-al (47) and -12-ol (54), italicen-15-al (2,11-c ycloacor-3-en-15-al, 52), the 6,10-epoxybisabolen-12-als 49, 50, 53, 58, 60 /61, ar-curcumen-15-al (62) and its 10,11-epoxides 76/77, epi-alpha-bisabol one (69), methyl (E)-trans-alpha-bergamota-2, 10-dien-12-oate (74) and its 2,3-epoxide 80. The so-called helifolen-12-als 35, 36, 42, 43, which were t race constituents of the Iranian Pulicaria gnaphalodes oil, belong to the m ain constituents (together 7.2%) of the Lantana oil. NaBH4 reduction of 35, 36, 42, 43 yielded the helifolen-12-ols A-D. Their structure was elucidate d by NOED and HMBC experiments and an X-ray analysis of the p-bromobenzenes ulphonate of helifolen-12-ol D. The helifolen-12-ols A-D are racemates. The refore, a biogenetic pathway via a bisaboladienyl and an acorenyl cation to the helifolen-12- (35, 36, 42, 43) and -15-als (38/39) is proposed. Copyri ght (C) 1999 John Wiley & Sons, Ltd.