Four New Compounds From Isodon eriocalyx

Examination of the chemical constituents of the dried leaves of Isodon eriocalyx (Dunn.) Hara led to the isolation of four new diterpenoids, named maoecrystal Q-T (1-4). Their structures were elucidated as $16(R)-methoxymethyl-6{\beta},\;7{\beta}-dihydroxy-7{\alpha},20-epoxy-ent-kaur-2,3-ethenylene-1$, 15-dione(1), $1{\beta},18-diacetoxy-6{\beta},7{\beta}-dihydroxy-7{\alpha},20-epoxy-ent-kaur-16-en-15-one\;(2),\;6{\beta},\;7{\beta}-dihydroxy-15{\beta}-acetoxy-7{\alpha},20-epoxy-ent-kaur-16-en-1-one$ (3) and $7{\beta}-hydroxy-6{\beta},15{\beta}-diacetoxy-1{\alpha},11{\beta}-acetonide-7{\alpha},20-epoxy-ent-kaur-16-ene$ (4), respectively, on the basis of spectroscopic methods. Meanwhile, five known diterpeonids eriocalyxin B (5), maoecrystal B-D (6-8) and trichokaurin (9) were also obtained.