Franco Piozzi

A chlorine-containing and two 17β-neo-clerodane diterpenoids from teucrium polium subsp. Vincentinum

Abstract From the aerial parts of Teucrium polium subsp. vincentinum three new neo-clerodane diterpenoids, teuvincentins A, B and C, have been isolated besides four already known diterpenes (19-acetylgnaphalin, eriocephalin, isoeriocephalin and 3-deacetyl-20- epi -teulanigin) and the flavones cirsiliol and apigenin. The structures of teuvincentin A [(12 S , 20 S )-20- O -acetyl-19-acetoxy-18-chloro-15,16-epoxy-4α,7-dihydroxy-6-oxo- neo -clerodane-7,13(16),14-triene-20,12-hemiacetal], B [12 S ,20 S )-20- O -acetyl-4α,18;15,16-diepoxy-6α-hydroxy-17β- neo -clerodane-13(16),14-diene-7α,19; 20,12-dihemiacetal] and C [12 S ,20 S )-20- O -acetyl-6α,19-diacetoxy-4α,18; 15,16-diepoxy-7-oxo-17β- neo -clerodane-13(16), 14-diene-20,12-hemiacetal] were established by chemical and spectroscopic means and, in the case of teuvincentins A and B, also confirmed by X-ray diffraction analyses of their acetyl derivatives.

Neo-clerodane diterpenoids from Scutellaria columnae

Abstract Three new neo-clerodane diterpenoids, scutecolumnins Aue5f8C, have been isolated from the acetone extract of the aerial parts of Scutellaria columnae subsp. columnae . The structures of these substances were established by spectroscopic means and by comparison with closely related compounds.

Neo-clerodane diterpenoids from Scutellaria alpina subsp. javalambrensis

Abstract Three new neo-clerodane derivatives, scutalpins B–D, were isolated from the acetone extract of the aerial parts of Scutellaria alpina subsp. javalambrensis . The structures of these compounds were established mainly by spectroscopic means as (11 S )-11,19-diacetoxy-4α,18-epoxy-8β-hydroxy-6α-tigloyloxy-13-neo-cleroden-15,16-olide (scutalpin B), (11 S )-19-acetoxy-4α,18-epoxy-8β,11-dihydroxy-6α-tigloyloxy-13-neo-cleroden-l5,16-olide (scutalpin C) and (13 S )-11β,19-diacetoxy-4α,18;8β,13-diepoxy-6α-tigloyloxy-neo-clerodan-15,16-olide (scutalpin D).

Neo-clerodane diterpenoids from Teucrium lanigerum

Abstract From the aerial part of Teucrium lanigerum , six new neo-clerodane diterpenoids, 7,8-dehydroeriocephalin, teulanigeral, teulanigin, 20-epi-teulanigin, teulanigerin and teulanigeridin, have been isolated. The first of these, 7,8-dehydroeriocephalin, is a natural substance, whereas the other compounds were isolated as their acetyl derivatives after acetylation of an inseparable mixture of natural diterpenoids. The structures of these substances were established mainly by spectroscopic means and, in the case of 7,8-dehydroeriocephalin, by partial synthesis from eriocephalin.

Isoeriocephalin and 20-deacetyleriocephalin, Neoclerodane Diterpenoids from Teucrium lanigerum

Abstract From the aerial part of Teucrium lanigerum two new neo-clerodane diterpenoids, 20-deacetyleriocephalin and isoeriocephalin, have been isolated, together with the previously known diterpene eriocephalin. The structures of 20-deacetyleriocephalin [19-acetoxy 4α,18:15,16-diepoxy-7α-hydroxy-6-keto-neo-cleroda-13(16),14-diene-20 S ,12 S -hemiacetal] and isoeriocephalin [19-acetoxy-4α,18:15,16-diepoxy-6α-hydroxy-7-keto-neo-cleroda-13(16),14-diene (20-acetyl)-20 S ,12 S -hemiacetal] were established by chemical and spectroscopic means and by correlation with known compounds.

Neo-clerodane diterpenoids from Teucrium polium subsp. capitatum

Abstract From the aerial part of Teucrium polium subsp. capitatum three new neo-clerodane diterpenoids, 7-deacetylcapitatin, picropolinol and 20-epi-isoeriocephalin, have been isolated, together with the previously known diterpenes picropolin, picropolinone, 19-acetylgnaphalin and teucjaponin B. The structures of 7-deacetylcapitatin [19-acetoxy-4α,18:15,16-diepoxy-7α-hydroxy-6-keto-neo-cleroda-13(16),14-dien-20,12S-olide], picropolinol [18,19-diacetoxy-15,16-epoxy-4α,6α-dihydroxy-7-keto-neo-cleroda-13(16),14-dien-20,12S-olide] and 20-epi-isoeriocephalin [19-acetoxy-4α,18:15,16-diepoxy-6α-hydroxy-7-keto-neo-cleroda-13(16),14-diene-(20-O-acetyl)-20R,12S-hemiacetal] were established by chemical and spectroscopic means and, in the case of 7-deacetylcapitatin and picropolinol, by correlation with known compounds.

Teuscorodin, teuscorodonin and 2-hydroxyteuscorolide, neo-clerodane diterpenoids from teucrium scorodonia

Abstract From the aerial part of Teucrium scorodonia (Labiatae) three new neo-clerodane diterpenoids have been isolated. Their structures, (12 S )-15,16-epoxy-2α-hydroxy-19-nor-neo-clerodane-4,6,13(16),14-tetraene-18,6:20,12-diolide (2-hydroxyteuscorolide), (12 S ,18 R )-15,16-epoxy-6-keto-neo-clerodane-13(16),14-dien-20,12-olide-18,19-hemiacetal (teuscorodin) and (12 S )-15,16-epoxy-19-hydroxy-neo-clerodane-3,13(16),14-triene-18,6β:20,12-diolide (teuscorodonin), have been established by chemical and spectroscopic means and by correlation with known products.

Two C-10 oxygenated neo-clerodane diterpenoids from Teucrium pestalozzae

Abstract From the aerial parts of Teucrium pestalozzae two new neo -clerodane diterpenoids, teupestalins A and B, have been isolated. The structures of teupestalin A (4α,18;15,16-diepoxy-6β,10β-dihydroxy- neo -cleroda-13(16),14-dien-20, 12 S -olide-3α,19-hemiacetal) and teupestalin B (19-acetoxy-4α,18;15,16-diepoxy-6-oxo- neo -cleroda-13(16),14-dien-20, 12 S -olide-3β,10⊝hemiacetal) were established by spectroscopic means and, in the case of teupestalin A, also by an X-ray diffraction analysis. Teupestalins A and B are the first C-10 oxygenated neo -clerodane derivatives found in plants belonging to the genus Teucrium .

Neo-clerodane diterpenoids from Teucrium pyrenaicum and T. subspinosum

Abstract From the aerial parts of teucrium pyrenaicum two new neo-clerodane diterpenoids, teupyrins A and B, have been isolated. The structures of teupyrin A [3β,12S-diacetoxy-4α,18; 15,16-diepoxy-6-keto-neo-cleroda-13(16),14-diene-20R,19-hemiacetal] and teupyrin B [6α-acetoxy-4α,18; 15,16-diepoxy-3β,12ξ,19-trihydroxy-neo-cleroda-13(16),14-diene] were established mainly by spectroscopic means and, in the case of teupyrin A, by X-ray diffraction analysis. The acetone extract of the aerial parts of T. subspinosum yielded four previously known neo-clerodane diterpenoids: teucvin, teuflin, teucrin H2 and 6α-hydroxyteuscordin.

Diterpenoids from Teucrium scorodonia, three neo-clerodane derivatives

Abstract From the aerial parts of Teucrium scorodonia the previously known diterpenoid teupolin I and the flavone luteolin have been isolated. In addition, three new neo-clerodane derivatives have also been obtained from the same source. The structures of these new natural diterpenoids have been established by chemical and spectroscopic means and by correlation with known products.