Lindsay H. Briggs

Degradation of the lanosterol side-chain

3β-Acetoxylanosta-8,24-diene (1) has been converted by a six-step degradation into 3β-acetoxy-4,4,14α-tri-methyl-5α-pregn-8-en-2-one (14).

Chemistry of the Coprosma genus. Part XIV. Constituents of five New Zealand species

The anthraquinone pigments of the barks of Coprosma tenuicaulis, C. linariifolia, C. rotundifolia, and C. propinqua and the heartwood of C. robusta are reported. C. linariifolia contains a new anthragallol 2-methyl ether 3-glycoside and C. rotundifolia a rubiadin 3-glycoside. A minor anthraquinone of C. lucida previously considered to be soranjidiol has been identified as lucidin. The presence of the coumarin scopoletin has been shown in the barks of a number of Coprosma species.

Solanum alkaloids. Part XVII. The sugar unit of solamargine

The sugar unit of solamargine (2; R = solasod-5-en-3β-yl) has been shown to be β-chacotriose {O-6-deoxy-α-L-mannopyranosyl-(1→2)-O-[6-deoxy-α-L-mannopyranosyl-(1→4)]-β-D-glucopyranose (2; R = H)}.

Chemistry of fungi. Part VIII. Constituents of Valsaria rubricosa and the identification of papulosin with valsarin

Valsarin (3), 7-chloroemodin (5), emodin, and mannitol have been isolated from Valsaria rubricosa. There is mass spectral evidence also for the presence of three further compounds, probably 5,7-dichloroemodin (6) parietin (7), and 1,2,4,5-tetrahydroxy-7-methylanthraquinone (8). ‘Papulosin’ has been shown to be identical with valsarin.

Diterpenes. Part X. Some transformations of phyllocladene and isophyllocladene

The products from, and the effect of solvent on the ring-opening of 15α,16-epoxyphyllocladane (1) and of 16,17-epoxyphyllocladane (17) with boron trifluoride have been examined. The action of other Lewis acids has also been investigated. Treatment of 15α,16-epoxykaurane (21) with boron trifluoride–ether complex results in rearrangement, giving atisiran-15-one (25).Photo-oxygenation of phyllocladene (6) and isophyllocladene (19) has been studied; a minor product from the latter reaction is 15α,16-epoxyphyllocladan-17-ol (2).