New physalins from Physalis angulata and Physalis lancifolia. Structure and reactions of physalins D, I, G and K

The structures of physalins I, G and K are established respectively as 5,6-dihydro-5α-methoxy-6β -hydroxy, 4,5-dehydro-5,6-dihydro-4β-hydroxy and 5,6-dihydro-4α,5α-epoxy-6α-hydroxy derivatives of physalin B. The chemistry of physalin D, and the synthesis of physalins D and I from physalin F and physalin K from physalin G are described