369. The chemistry of fungi. Part XXXI. The structure of rosenonolactone

Abstract

Dehydrogenation of rosenonolactone, a metabolite of Trichotheciuin roseunz Link, and of dihydroisorosenonolactone gives 1 : 7-dimethyl-and 9-hydroxy-1 : 7-dimethyl-phenanthrene, a result which, in conjunction with the composition and properties of the lactones, shows that they are diterpenoid derivatives having the same nucleus. Rosenono-and isorosenono-lactone and their derivatives are y-lactones, an examination of which in conjunction with earlier work 1 enables provisional structures t o be ascribed to the metabolite and its degradation products.

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“…The correlation between ring size and the frequency of the carbonyl absorption in the infrared spectrum played an important role in the identification of the ring size of ketones, lactones, and cyclic anhydrides. 72 This is exemplified by the characterization of the functional groups of the plant hormone, gibberellic acid 54, 73 and by the studies on the diterpenoid fungal metabolite rosenonolactone 55 in which the presence of the γ-lactone (ν max 1786 cm Ϫ1 ) and the cyclohexanone (ν max 1724 cm Ϫ1 ) were established 74 by infrared spectroscopy.…”

Isolation of an l-Epimer of Natural d-α-Tocopherol

“…Melting points for the /-acetate and acid succinate were lower than for the corresponding d-esters. 4 'd,8 'D-a-tocopherol prepared by the fractionation procedure was judged to be identical with natural d-a-tocopherol from the data shown in Table I for the free tocopherols, oxidation products, crystalline acetates and acid succinates.…”

The stereochemistry of the Grignard reaction of some boat ring ketones in the diterpenoids

“…Rosenonolactone 1 4 and rosololactone 3 5 are two diterpenoid lactones in which the presence of a β-oriented 19-10 γ-lactone and a C-9β methyl group constrains ring B to adopt a boat conformation. 6 Treatment of the C-7 ketone 1 with methylmagnesium bromide gave a good yield of a single crystalline tertiary alcohol.…”