New diterpenes from Sideritis sicula

Two new diterpenes have been isolated from Sideritis sicula: sideripol, ent-18-acetoxy-7α-hydroxykaur-15-ene and epoxysideritriol, ent-15β,16β-epoxykauran-7α,17,18-triol. The previously known diterpene eubol, ent-7α-acetoxykaur-16-en-15β,18 diol has also been obtained from the same source.     

Inhibitors of sterol biosynthesis. Syntheses of 14α-alkyl substituted 15-oxygenated sterols

The chemical syntheses of a number of 14α-alkyl substituted 15-oxygenated sterols have been pursued to permit evaluation of their activity in the inhibition of the biosynthesis of cholesterol and other biological effects. Described herein are the first chemical syntheses of 14α-ethyl-5α-cholest-7-en-3β-ol-15-one, bis-3β,15α-acetoxy-14α-ethyl-5α-cholest-7-ene, 3β-acetoxy-14α-ethyl-5α-cholest-7-en-15β-ol, 14α-ethyl-5α-cholest-7-en-3β,15β-diol, 14α-ethyl-5α-cholest-7-en-3β,15α-diol, 3β-hexadecanoyloxy-14α-ethyl-5α-cholest-7-en-15α-ol, 3β-hexadecanoyloxy-14α-ethyl-5α-cholest-7-en-15β-ol, bis-3β,15α-hexadecanoyloxy-14α-ethyl-5α-cholest-7-ene, 3β-hexadecanoyloxy-14α-ethyl-5α-cholest-7-en-15-one, 3α-benzoyloxy-14α-ethyl-5α-cholest-7-en-15-one, 14α-ethyl-5α-cholest-7-en-3α-ol-15-one, 14α-ethyl-5α-cholest-7-en-15-on-3β-yl pyridinium sulfate, 14α-ethyl-5α-cholest-7-en-15-on-3β-yl potassium sulfate (monohydrate), 14α-ethyl-5α-cholest-7-en-15-on-3α-yl pyridinium sulfate, 14α-ethyl-5α-cholest-7-en-15-on-3α-yl potassium sulfate (monohydrate), 3β-ethoxy-14α-ethyl-5α-cholest-7-en-15-one, 3β-acetoxy-14α-n-propyl-5α-cholest-7-en-15-one, 14α-n-propyl-5α-cholest-7-en-3β-ol-15-one, bis-3β, 15α-acetoxy-14α-n-propyl-5α-cholest-7-ene, 3β-acetoxy-14α-n-propyl-5α-cholest-7-en-15β-ol, 14α-n-propyl-5α-cholest-7-en-3β, 15α-diol, 14α-n-propyl-5α-cholest-7-en-3β, 15β-diol, 14α-n-butyl-5α-cholest-7-en-3β-ol-15-one, 3β-acetoxy-14-α-n-butyl-5α-cholest-7-en-15-one, bis-3β,15α-acetoxy-14α-n-butyl-5α-cholest-7-ene, 3β-acetoxy-14α-n-butyl-5α-cholest-7-en-15β-ol, 14α-n-butyl-5β-cholest-7-en-3β, 15β-diol, and 14α-n-butyl-5α-cholest-7-en-3β, 15α-diol.     

Orgogenin,a pregnane derivative from orthenthera viminea

A new pregnane genin designated as orgogenin has been isolated from Orthenthera viminea and characterized to be 20-oxo-pregn-5-ene, 3β,8β,11α,12β,14β,15α-hexol.     

Trichothecene mycotoxins from Fusarium sulphureum

Four mycotoxins isolated from moulded maize cultures of Fusarium sulphureum have been characterized as 3α,4β,15-triacetoxy-12,13-epoxytrichothec-9-ene, 4β,15-diacetoxy-3α-hydroxy-12,13-epoxytrichothec-9-ene, 15-acetoxy-3α,4β-dihydroxy-12,13-epoxytrichothec-9-ene and 4β-acetoxy-3α,15-dihydroxy-12,13-epoxytrichothec-9-ene.     

Integrifolin,a guaianolide from Andryala integrifolia

Integrifolin, the major constituent of Andryala integrifolia, has been isolated and characterized as 3β,8β-dihydroxy-4(15),10(14),11(13)-trien-(1αH), (5αH) guaian-6,12-olide (8-epi-desacylcynaropicrin).     

Epoxy-isosidol: A new diterpenoid from Sideritis biflora

The new diterpenoid ent-3β-acetoxy-7α,18-dihydroxy-15β,16-epoxykaurane has been isolated from Sideritis biflora. Twelve previously known ent-kaurane derivatives have also been obtained from the same source.     

New sesquiterpene lactones from Inula oculus-christi L.

Investigation of the aerial parts of Inula oculus-christi L. led to the identification of four new sesquiterpene lactones: an eudesmanolide (4α,15α-epoxypulchellin E) and three guaianolides (2α-acetoxy-4α,9β-dihydroxy-1β-guaia-11(13),10(14)-dien-12,8α-olide, 9β,10β-epoxygaillardin, 9α,10α-epoxy-2-epi-gaillardin), in addition to the known gaillardin, pulchellin E, pulchellin C and 3-O-palmitates of 16β-hydroxylupeol, 16β-hydroxy-β-amyrin, and faradiol. The structures of all compounds have been elucidated on the basis of their spectral data.     

The facile bioconversion of testosterone by alginate-immobilised filamentous fungi

The potential for biotransformation of the substrate 17β-hydroxyandrost-4-en-3-one (testosterone) by six filamentous fungi, namely, Rhizopus oryzae ATCC 11145, Mucor plumbeus ATCC 4740, Cunninghamella echinulata var. elegans ATCC 8688a, Aspergillus niger ATCC 9142, Phanerochaete chrysosporium ATCC 24725 and Whetzelinia sclerotiorum ATCC 18687, was investigated. In this study both free cells and macerated mycelia immobilised in calcium alginate were utilised and the results (products, % yields, % transformation) were compared. In general the encapsulated cells of the microorganisms effectively generated products similar to those found using free cells. However, with immobilised macerated mycelia, isolation of the transformation products was expedited by the simple work up procedure, and their purification was facilitated by the absence of fungal secondary metabolites. Twenty seven analogues of testosterone were generated, wherein the androstane skeleton was functionalised at C-1β, -2β, -6β, -7α, -11α, -14, -15α, -15β and -16β by the moulds. Redox chemistry was also observed. Seven of the analogues, 6β,11α,17β-trihydroxyandrost-4-en-3-one, 6β,14α,17β-trihydroxyandrost-4-en-3-one, 2,6β-dihydroxyandrosta-1,4-diene-3,17-dione, 2β,16β-dihydroxyandrost-4-ene-3,17-dione, 2β,6β-dihydroxyandrost-4-ene-3,17-dione, 2β,15β,17β-trihydroxyandrost-4-en-3-one and 2β,3α,17β-trihydroxyandrost-4-ene, were novel compounds. Five others, namely, 7α,17β-dihydroxyandrost-4-en-3-one, 6β,14α-dihydroxyandrost-4-ene-3,17-dione, 15α,17β-dihydroxyandrost-4-en-3-one, 16β,17α-dihydroxyandrost-4-en-3-one and 2β,16β,17β-trihydroxyandrost-4-en-3-one, were fully characterised for the first time.     

Four new sesquiterpene polyol esters from Celastrus angulatus

Celastrus species, such as Celastrus angulatus, has been demonstrated to be very rich in natural sesquiterpene polyol esters sharing the β-dihydroagarofuran skeleton, some of which showed various biological activities. In this paper, four new sesquiterpene polyol esters, named as angulatins K-N (1–4), along with three known ones, 1β-acetoxy-9β-benzoxy-4α, 6α-dihydroxy-8α, 15-diisobutanoyloxy-2β-(α-methyl)-butanoyloxy-β-dihydroagarofuran, angulatin A, and celangulin III, were isolated from the root bark of C. angulatus. The structures of the new compounds were elucidated by extensive spectroscopic methods, mainly including HR-MS and 1D and 2D NMR techniques.     

Labdane diterpenes from an acacia species

Two new diterpenes, (13E)-labd-13-ene-3β,8α,15-triol and (13E)-3β,8α-dihydroxylabd-13-en-15-oic acid have been isolated from an unclassified Acacia sp. Chemical and spectroscopic evidence for their structure is presented. The known labdanes, sclareol, 13-epi-sclareol and (13E)-labd-13-ene-8α,15-diol were also isolated.     

Microbial hydroxylation of 2-oxatestosterone

An investigation has been undertaken of the microbial biotransformation of 2-oxatestosterone by microorganisms known to hydroxylate conventional steroids, using Aspergillus ochraceus, Bacillus megaterium, Curvularia lunata and Rhizopus arrhizus. A. ochraceus and B. megaterium gave products of 11α- and 15β-hydroxylation, respectively. Biotransformation by C. lunata gave C-11β- and C-14α-hydroxylated products, whereas R. arrhizus produced only the 6β-hydroxy derivative.     

Chemical syntheses of 5α-cholesta-6,8(14)-dien-3β-ol-15-one and related 15-oxygenated sterols

Hydroboration of 5α-cholesta-8,14-dien-3β-ol (I) gave 5α-cholest-8-en-3β,15α-diol (IV) in 89% yield. 5α-Cholest-7-en-3β,15α-diol (V) was prepared in 91% yield by hydroboration of 5α-cholesta-7,14-dien-3β-ol (II). Hydroboration of 27:63 mixture of I and II gave IV and V in 18% and 70% yields, respectively. 5α-Cholest-8-en-15α-ol-3-one and 5α-cholest-7-en-15α-ol-3-one were prepared in high yields from IV and V, respectively, by either selective oxidation with silver carbonate-celite or by enzymatic oxidation using cholesterol oxidase. 7α,8α-Epoxy-5α-cholestan-3β,15α-diol (VIII) was prepared in 93% yield by treatment of V with m-chloroperbenzoic acid. 5α-Cholest-8(14)-en-7α-ol-3,15-dione (IX) was prepared in 56% yield by oxidation of VIII with pyridinium chlorochromate followed by treatment of the crude product with acid. Compound IX was also obtained in 72% yield by selective chemical oxidation of 5α-cholest-8(14)-en-3β,7α,15α-triol. 5α-Cholesta-6,8(14)-dien-3,15-dione (X) was prepared in 89% yield by treatment of IX with p-toluenesulfonic acid under controlled conditions. Reduction of X with lithium tri-tert-butoxyaluminum hydride under controlled conditions gave 5α-cholesta-6,8(14)-dien-3β-ol-15-one in 84% yield.     

Labdane diterpenoids from Cistus ladaniferus

Three new diterpenic acids have been isolated from Cistus ladaniferus: 6,8(17) labdadien-15-oic, 7-oxo-8-labden-15-oic and 6β-acetoxy-7-oxo-8-labden-15-oic acids, beside labdanolic, 6-oxocativic,7α-hydroxy-8(17)-labden-15-oic, 8α-methoxy-labda-15-oic and 8α-hydroxy-13(E)-labden-15-oic acids.     

Concerning the structure of 7α,15β-dichloro-5α-cholest-8(14)-en-3β-ol,a novel inhibitor of cholesterol biosynthesis

Treatment of 3β-p-bromobenzoyloxy-14α, 15α-epoxy-5α-cholest-7-ene with gaseous HCI in chloroform at ?25°C gave 3β-p-bromobenzoyloxy-7α, 15β-dichloro-5α-cholest-8(14)-ene in 93% yield. The structure of the latter compound was unequivocally established by the results of X-ray crystallographic analysis.     

Application of α- and β-naphthoflavones as monooxygenase inhibitors of Absidia coerulea KCh 93, Syncephalastrum racemosum KCh 105 and Chaetomium sp. KCh 6651 in transformation of 17α-methyltestosterone

In this work, 17α-methyltestosterone was effectively hydroxylated by Absidia coerulea KCh 93, Syncephalastrum racemosum KCh 105 and Chaetomium sp. KCh 6651. A. coerulea KCh 93 afforded 6β-, 12β-, 7α-, 11α-, 15α-hydroxy derivatives with 44%, 29%, 6%, 5% and 9% yields, respectively. S. racemosum KCh 105 afforded 7α-, 15α- and 11α-hydroxy derivatives with yields of 45%, 19% and 17%, respectively. Chaetomium sp. KCh 6651 afforded 15α-, 11α-, 7α-, 6β-, 9α-, 14α-hydroxy and 6β,14α-dihydroxy derivatives with yields of 31%, 20%, 16%, 7%, 5%, 7% and 4%, respectively. 14α-Hydroxy and 6β,14α-dihydroxy derivatives were determined as new compounds. Effect of various sources of nitrogen and carbon in the media on biotransformations were tested, however did not affect the degree of substrate conversion or the composition of the products formed. The addition of α- or β-naphthoflavones inhibited 17α-methyltestosterone hydroxylation but did not change the percentage composition of the resulting products.     

Triterpenes in Ganoderma lucidum

Four new oxygenated triterpenes, isolated from the mycelia of the fungus Ganoderma lucidum, were determined to be lanosta-7,9(11),24-trien-3α, 15α-dihydroxy-26-oic acid, lanosta-7,9(11),24-trien-3β, 15α-dihydroxy-26-oic-acid, lanosta-7,9(11),24-trien-3β,22β-diacetoxy-15α-hydroxy-26-oic acid and lanosta-7,9(11),24-trien-15α,22β-diacetoxy-3β-hydroxy-26-oic acid by spectroscopic methods.     

Selective oxidation of steroidal allylic alcohols

Pyridinium chlorochromate in CH₂Cl₂ containing pyridine (2%) at 2—3°C has been found to effect the high yield selective oxidation of the hydroxyl function of a number of steroidal allylic alcohols. Under these conditions the oxidation of cholest-4-cn-3β-ol to the corresponding ketone was effected in 92% yield. Only the allylic hydroxyl function of 5α-cholest-8(14)-ene-3β,15α-diol, 5α-cholest-8(14)ene-3β,15β-diol and 5α-cholest-8(14)-ene-3β,7β-diol was oxidized under these conditions to give the corresponding α,β-unsaturated ketones in high yields. 5α-Cholest-8(14)-ene-3β,7α,15α-triol gave 5α-cholest-8(14)-ene-3β,7α-diol-15-one in 82% yield. Attempted oxidations of the 5α-cholestan-3β,15α-diol and 5α-cholest-7-ene-3β,15α-diol, both lacking an allylic hydroxyl function, under these conditions, were unsuccessful. Selective oxidation of the allylic alcohol function of 5α-cholest-8(14)-ene-3β,15β-diol using activated manganese dioxide gave 5α-cholest-8(14)-en-3β-ol-15-one in high yield while oxidation of the corresponding 15α-hydroxy epimer using manganese dioxide was unsuccessful.     

Gymnospermin: A new labdan triol from Gymnosperma glutinosa

The structure of gymnospermin (1), a new diterpene triol isolated from a collection of Gymnosperma glutinosa (Compositae) from Mexico, has been determined to be (?)-7β,8α,15-trihydroxy-labdan.     

Biotransformation of the diterpene 15β-hydroxy-18(4→3)-abeo-ent-kaur-4(19),16-diene by the fungus Fusarium fujikuroi

15β-Hydroxy-18(4→3)-abeo-ent-kaur-4(19),16-diene (4) was biotransformed by the fungus Fusarium fujikuroi into 3α,11β,15β-trihydroxy-18(4→3)-abeo-ent-kaur-4(19),16-diene (5). The hydroxylation at C-3(α) in this diterpene reminds a similar reaction that occurs at C-13 in the biosynthesis of gibberellic acid in this fungus. The presence of the 15β-alcohol in the substrate directs the second hydroxylation at C-11(β), which had been observed in the incubation of ent-kaur-16-ene derivatives with this fungus when the C-19 hydroxylation was inhibited by the existence in the molecule of a 3α-OH or 3-oxo group. We also show that the angelate of the substrate is an undescribed natural product now identified as a component of the plant Distichoselinum tenuifolium.     

Biotransformation of methyl cholate by Aspergillus niger

Biotransformation of methyl cholate using Aspergillus niger was investigated. This led to the isolation of two derivatives: methyl 3α,7α,12α,15β-tetrahydroxy-5β-cholan-24-oate identified as a new compound, and a known compound methyl 3α,12α-dihydroxy-7-oxo-5β-cholan-24-oate. The structure elucidation of the new compound was achieved using 1D and 2D NMR, MS and X-ray diffraction.