Phytoecdysones ofRhaponticum integrifolium III. Integristerone B
SummaryFrom the flower heads ofRhaponticum integrifolium we have isolated a new phytoecdysone — integristerone B. It has been shown that it is 1β, 2β, 3β, 5β, 14α, 20R, 22R, 25-octahydroxy-5β-cholest-7-en-6-one.
Insect Moulting Hormones: Dacrysterone, a New Phytoecdysone From Dacrydium intermedium
Dacrysterone, a new phytoecdysone, has been isolated from the bark of Dacrydium intermedium and shown to be 5β-hydroxymakisterone A (6). Makisterone A also occurs in this plant.
Brauer groups of genus zero extensions of number fields
We determine the isomorphism class of the Brauer groups of certain nonrational genus zero extensions of number fields. In particular, for all genus zero extensions E of the rational numbers Q that are split by Q(√2), Br(E) ≅ Br(Q(t)).