An investigation into the natural products chemistry of the sea hare Aplysia dactylomela.

Abstract

A diterpenoid alcohol, C(, 20)H(, 32)O(, 3), which was characterized as a novel isomer of the known diterpenoid dolatriol, was also isolated from the chloroform extract.

The chemistry of the sea hare, Aplysia dactylomela, was investigated during a routine search for anticancer compounds. In the process, thirteen compounds were isolated and characterized.

The chloroform soluble extract yielded a number of novel diterpenoids. The structure of parguerol (1), a pimarane type diterpene alcohol with significant cytotoxicity, was elucidated by extensive proton NMR decoupling of the parent alcohol, acetate, and benzoate derivatives at

Four novel compounds, similar to parguerol, were also isolated from the chloroform extract. One compound, C(, 24)H(, 35)BrO(, 6) was a simple acetate derivative while another, C(, 22)H(, 33)BrO(, 4), was a deoxyderivative. Two compounds, C(, 22)H(, 33)BrO(, 5) and C(, 24)H(, 35)BrO(, 6), were found to contain a cyclobutane ring rather than a cyclopropane ring as found in parguerol.

270 and 360 MHz. Chemical transformations such as ozonolysis, oxidation, and zinc reduction were also carried out.

The hexane soluble and carbon tetrachloride soluble extracts yielded the tribromoindole C(, 9)H(, 6)NBr(, 3) and several interesting sesquiterpenoids. Along with elatol and allolaurinterol acetate, two interconverting chamigrene isomers, C(, 15)H(, 20)Br(, 2)O have been isolated. Isoobtusol acetate was isolated from a less polar fraction, and its structure was established by complete proton decoupling and analogy with many known chamigrenes. Dihydroxydeodactol monoacetate was determined by analogy with the known compound deodactol, 270 MHz proton decoupling, and chemical transformations.