Alfredo Ortega

Constituents of zaluzania species—II : Structures of zaluzanin C and Zaluzanin D

Abstract Zaluzanin C a constituent of Zaluzania augusta (Lag.) Schultz, Bip. and Z. triloba Pers has been shown to be a guaianolide with structure Ia. Zaluzanin D another constituent of Z. triloba was identified as acetylzaluzanin C (Ib). The eudesmanolide ivalin (XI) was also isolated from Z. triloba .

neo-Clerodane diterpenes from Salvia herbacea

Chemical investigation of the aerial parts of Salvia herbacea led to the isolation of eight new neo-clerodane diterpenes (1-8), named tehuanins A-H, and three known compounds. The structures of these compounds were determined by analysis of their spectroscopic data. Three of the new diterpenes possess a 1,8-epoxy group (1-3). This unusual structural feature was confirmed by X-ray diffraction of 1. The structure of the previously isolated 1α,10α-epoxysalviarin was revised. The absolute configuration of 6 was established by X-ray diffraction analysis of its bromo derivative 6a. Cytotoxic and anti-inflammatory activities of these diterpenes were examined. None of the compounds were considered to be cytotoxic; however, compound 7 exhibited anti-inflammatory activity comparable to that of indomethacin.

Methyl dodonates, a new type of diterpenes with a modified clerodane skeleton from Dodonaea viscosa

Abstract Three new modified clerodanes (10, 12, 17) containing a tricyclo[5.4.0.01,3]undecane ring system were isolated from Dodonaea viscosa. These types of compounds have not been found in nature until now, but they have been proposed as hypothetical intermediates in the biogenetic pathway of diterpenes possessing bicyclo[5.4.0]undecane or bicyclo[5.3.0]decane ring systems. In support of this hypothesis, 17 was transformed into the bicyclo[5.4.0]undecane derivative 20. Additionally, we isolated the new 5,10-secoclerodane 21 and several known diterpenes. The structures were elucidated by spectroscopic methods, chemical reactions and X-ray diffraction analysis.

Neo-clerodane-type diterpenoids from Salvia keerlii

Abstract From the aerial parts of Salvia keerlii two new neo-clerodane diterpenoids have been isolated. Their structures: 8,12( R )epoxyneo-cleroda-3,13(14)-diene-18,19:15,16-diolide, kerlin and 7-acetoxy-12( R )hydroxyneoclerodane-3,13(14)-diene-18,19:15,16-diolide, kerlinolide, have been established by spectroscopic means. X-ray diffraction analysis was performed for kerlin.

Structure and stereochemistry of zexbrevin, A 3 (2H) furanone germacranolide☆

Abstract Formulation of zexbrevin as 1 is based mainly on analysis of the NMR spectral of zexbrevin ( 1 ) and of the ketone 8 (Tables I and II).

Hydroxyclerodanes from Salvia shannoni

Six new hydroxyclerodanes (1-6), named sepulturins A-F, and four known diterpenes were isolated from the leaves of Salvia shannoni. The structures of these compounds were established by extensive analysis of their NMR and MS spectroscopic data. The relative configurations of compounds 1 and 2 were determined by NOESY experiments and were confirmed by single-crystal X-ray diffraction studies. All of the isolated diterpenes possess tertiary OH groups. The structure of infuscatin (7), a clerodane previously isolated from S. infuscata, was revised. Cytotoxic, antiprotozoal, and anti-inflammatory activities of these compounds were evaluated.

5,10-seco-neo-Clerodanes and neo-Clerodanes from Salvia microphylla

Two new 5,10-seco-neo-clerodanes, salvimicrophyllins A and B (1 and 2), and two new neo-clerodanes, salvimicrophyllins C and D (3 and 4), were isolated from the leaves and flowers of Salvia microphylla. The structures of these compounds were elucidated mainly by analysis of their NMR spectroscopic and mass spectrometric data. The relative configurations of the salvimicrophyllins were determined by analysis of NOESY spectra and ECD curves, and the relative configuration of compound 2 was confirmed by single-crystal X-ray diffraction crystallography.

Salviandulines A and B. Two secoclerodane diterpenoids from Salvia lavanduloides

Abstract Two novel 9,10-secoclerodane diterpenoids, salviandulines A and B, were isolated from aerial parts of Salvia lavanduloides . Their structures were established by high resolution NMR and X-ray diffraction analysis.

Microphyllandiolide, a New Diterpene with an Unprecedented Skeleton from Salvia microphylla

Microphyllandiolide (1), an unprecedented rearranged clerodane-type diterpene with a 9/3 bicyclic ring system, was isolated from the aerial parts of Salvia microphylla Kunth. Its structure was elucidated by analysis of its spectroscopic data and confirmed by single crystal X-ray diffraction analysis. A possible biogenesis for microphyllandiolide (1) is proposed.

Diterpenoids from Viguiera insignis

Abstract The isolation of several known diterpenoids and one new diterpene diol from aerial parts of Viguiera insignis is reported.