Anticancer Agents from the Australian Tropical Rainforest: Spiroacetals EBC‐23, 24, 25, 72, 73, 75 and 76

Abstract

EBC-23, 24, 25, 72, 73, 75 and 76 were isolated from the fruit of Cinnamomum laubatii (family Lauraceae) in the Australian tropical rainforests. EBC-23 (1) was synthesized stereoselectively, in nine linear steps in 8 % overall yield, to confirm the reported relative stereochemistry and determine the absolute stereochemistry. Key to the total synthesis was a series of Tietze-Smith linchpin reactions. The novel spiroacetal structural motif, exemplified by EBC-23 (1), was found to inhibit the growth of the androgen-independent prostate tumor cell line DU145 in the mouse model, indicating potential for the treatment of refractory solid tumors in adults.

Understanding the Reactivity of Acyl Anion Equivalents: The Epoxide Ring Opening Case

“…Previous work [22] had demonstrated that these epoxides undergo smooth ring opening when reacted with either the anion of dithiane 4a or the TMS-dithane 4b and as such acted as a benchmark to dithiane reactivity.…”

“…Our group has previously experienced this problematic issue first hand. [22] With a desire to gain a general understanding of AAE reactivity and overcome, or avoid, S-alkylation we searched the literature, which to our surprise unveiled a substantial paucity of work in this area. For example, there were no comparative reactivity studies of known AAEs and no clear understanding or description as to why sulfur was a common functional group element.…”

Metathetic Synthesis of Common and Medium-Sized Lactones: The State of the Art

“…The second compound is EBC 23 96, isolated from Cinnamon laubatii, which is an inhibitor of the growth of androgen-independent prostate tumor cells. The preparation of 96 involves a RCM step aided by microwave irradiation [167,168] (Scheme 35).…”

A Contemporary Introduction to Essential Oils: Chemistry, Bioactivity and Prospects for Australian Agriculture

“…In the most basic test for anticancer activity immortalized cancer cells are grown in a culture and examined for survival or suppression under conditions of the respective treatment [67]. For antioxidant or free radical scavenging activity, a coloured free radical can be reduced by the treatment and made invisible to the naked eye, with the results quantified by a spectrophotometer on the visible spectrum [68].…”