15-O-Deacetylrhaposerin and rhaserin -- new components of a lactone mixture from Rhaponticum serratuloides

As part of our continuing studies of lactones from the aerial part of the plant Rhaponticum serratuloides, 15-O-deacetylrhaposerin and new guaianolide called rhaserin were isolated along with the well-known loliolide. The configuration of the C(17) asymmetric center in 15-O-deacetylrhaposerin was established by X-ray diffraction analysis. The molecular structure of rhaserin was determined based on the data from ¹H and ¹³C NMR spectroscopy (including 2D NMR spectroscopy) of this lactone and its 4,15-O-isopropylidene derivative.     

Synthesis of 11-hydroxydrim-8(9)-en-7-one and 11,12-dihydroxydrim-8(9)-en-7-one from drim-8(9)-en-7-one

A synthetic route to 11-hydroxydrim-8(9)-en-7-one and 11,12-hydroxydrim-8(9)-en-7-one, valuable key intermediates for the preparation of naturally occurring biologically active drimanic sesquiterpenoids, starting from easily available drim-8(9)-en-7-one was developed. 11-Hydroxydrim-8(9)-en-7-one was obtained by peracidic oxidation of the enol acetate of drim-8(9)-en-7-one. 11,12-Dihydroxydrim-8(9)-en-7-one was synthesized from drim-8(9)-en-7-one by two routes, namely, by a five-step procedurevia 11-hydroxydrim-8(9)-en-7-one and by bromination of drim-8(9)-en-7-one with NBS to give 11,12-dibromodrim-8(9)-en-7-one followed by its acetoxylation and deacetylation. Deceased Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 95–98, January, 2000.     

Phytochemical Profile and Anticancer Potential of Endophytic Microorganisms from Liverwort Species,Marchantia polymorpha L.

Liverwort endophytes could be a source of new biologically active substances, especially when these spore-forming plants are known to produce compounds that are not found in other living organisms. Despite the significant development of plant endophytes research, there are only a few studies describing liverwort endophytic microorganisms and their metabolites. In the presented study, the analysis of the volatile compounds obtained from thallose liverwort species, Marchantia polymorpha L., and its endophytes was carried out. For this purpose, non-polar extracts of plant material and symbiotic microorganisms were obtained. The extracts were analyzed using gas chromatography coupled to mass spectrometry. Compounds with the structure of diketopiperazine in the endophyte extract were identified. Liverwort volatile extract was a rich source of cuparane-, chamigrane-, acorane-, and thujopsane-type sesquiterpenoids. The cytotoxicity of ethyl acetate extracts from endophytic microorganisms was evaluated on a panel of cancer (FaDu, HeLa, and SCC-25) cell lines and normal (VERO), and revealed significant anticancer potential towards hypopharyngeal squamous cell carcinoma and cervical adenocarcinoma.     

Characterization of Eight New Secondary Metabolites from the Mutant Strain G‐444 of Tubercularia sp. TF5

Eight new metabolites, including five new sesquiterpenoids, 10,11‐epoxyguaian‐10‐ol ( 1 ), 10,11‐epoxyguaian‐13‐ol ( 2 ), a new backbone sesquiterpene rearranged from guaiane ( 3 ), two 1,5 : 1,10‐disecoguaianes, 4 and 5 , two new dihydroisocoumarins, 7‐chloromellein‐4‐ol ( 6 ) and 7‐chloromellein‐5‐ol ( 7 ), and one new tetralone, 7‐chloroscytalone ( 8 ), were isolated from the mutant strain G‐444 of Tubercularia sp. TF5, an endophytic fungus of Taxus mairei, along with ten known compounds, 3,4‐dihydro‐4,8‐dihydroxy‐2H‐naphthalen‐1‐one ( 9 ), (3R,4S)‐4‐hydroxymellein ( 10 ), 5‐formylmellein ( 11 ), 5‐carboxymellein ( 12 ), sporogen‐AO1 ( 13 ), tuberculariols A ( 14 ) and B ( 15 ), hymatoxin E ( 16 ), 4‐oxo‐4H‐pyran‐3‐acetic acid ( 17 ), and penicillic acid ( 18 ). Their structures were elucidated by spectroscopic analyses including HR‐ESI‐MS, 1D‐ and 2D‐NMR (HMQC, HMBC, ¹H,¹H‐COSY and NOESY). The antimicrobial activities of 1 – 8 were evaluated, but none showed any substantial effect.     

Genus Smenospongia: Untapped Treasure of Biometabolites—Biosynthesis,Synthesis, and Bioactivities

Marine sponges continue to attract remarkable attention as one of the richest pools of bioactive metabolites in the marine environment. The genus Smenospongia (order Dictyoceratida, family Thorectidae) sponges can produce diverse classes of metabolites with unique and unusual chemical skeletons, including terpenoids (sesqui-, di-, and sesterterpenoids), indole alkaloids, aplysinopsins, bisspiroimidazolidinones, chromenes, γ-pyrones, phenyl alkenes, naphthoquinones, and polyketides that possessed diversified bioactivities. This review provided an overview of the reported metabolites from Smenospongia sponges, including their biosynthesis, synthesis, and bioactivities in the period from 1980 to June 2022. The structural characteristics and diverse bioactivities of these metabolites could attract a great deal of attention from natural-product chemists and pharmaceuticals seeking to develop these metabolites into medicine for the treatment and prevention of certain health concerns.     

Oxidative bromination of tricyclic sesquiterpenoids (1S,3S,5R,6S,9S)-5-hydroxy-6,10,10-trimethyl-tricyclo[7.2.0.01,6]udecan-2-one and clovane-2β,9α-diol with the HBr—DMSO system

Oxidation of tricyclic sesquiterpenoids of the caryophyllene type with the HBr—DMSO system afforded ,-unsaturated -bromoketones. Since tricyclic derivatives, unlike simple alicyclic ketones, cannot undergo aromatization, all intermediate oxidation products can be isolated, which provide evidence that oxidation proceeds according to the following scheme: ketone-bromoketone,-dibromoketone,-unsaturated -bromoketone.     

Synthesis of drim-8(9)-en-7-one,drima-5,8(9)-dien-7-one,and their 11,12-dibromo derivatives from norambreinolide

A method was elaborated for the synthesis of polyfunctional compoonds of the drimane series,viz., drim-8(9)-en-7-one, drima-5,8(9)-dien-7-one, and their 11,12-dibromo derivatives, potential intermediates for the synthesis of natural biologically active drimane sesquiterpenoids starting from norambreinolide. The key intermediate of the above drimane compounds is methyl 7-oco-11-homodrim-8(9)-en-12-oate, prepared by electrochemical oxidation of a mixture of isomeric methyl bicyclohomofarnesenoates obtained from norambreinolide.Institutul de Chimie, Academia de Stiinte Republica Moldova, 3 str. Academiei, 277028 Chisinäu, Republica MoldovaTranslated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 216–222, January, 1996.     

Selective synthesis of carvone and cryptomerlone from α-pinene

Carvone and cryptomerlone were synthesized selectively using electrochemical oxidation of α-pinene in the key step. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 248–250, May–June, 2006.     

Synthesis of two new chloro derivatives of the guaianolide grossmisin and the crystal structure of one derivative

The reaction of grossmisin (8α-hydroxyachillin,1) with chlorine in benzene afforded a mixture of products. The less polar product readily crystallized after chromatography. According to the X-ray diffraction data, this product has the structure of 1α,10β-dichloro-1,10-dihydrogrossmisin. The second chloro derivative of grossmisin,viz., 8β-chloroachillin, was prepared in good yield by the reaction of lactone1 with PCl₅ in CHCl₃ in the presence of Py. Published inIzvestiya Akademii Nauk Seriya Khimicheskaya, No. 11, pp. 1932–1934, November, 2000.     

Synthesis of 11-hydroxydrim-8(9)-en-7-one and 11,12-dihydroxydrim-8(9)-en-7-one from drim-8(9)-en-7-one

A synthetic route to 11-hydroxydrim-8(9)-en-7-one and 11,12-hydroxydrim-8(9)-en-7-one, valuable key intermediates for the preparation of naturally occurring biologically active drimanic sesquiterpenoids, starting from easily available drim-8(9)-en-7-one was developed. 11-Hydroxydrim-8(9)-en-7-one was obtained by peracidic oxidation of the enol acetate of drim-8(9)-en-7-one. 11,12-Dihydroxydrim-8(9)-en-7-one was synthesized from drim-8(9)-en-7-one by two routes, namely, by a five-step procedurevia 11-hydroxydrim-8(9)-en-7-one and by bromination of drim-8(9)-en-7-one with NBS to give 11,12-dibromodrim-8(9)-en-7-one followed by its acetoxylation and deacetylation. Deceased Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 95–98, January, 2000.