A Rare New Cleistanthane Diterpene from the Pericarp of Trewia nudiflora

A minor, unprecedented diterpene, 3β,17‐dihydroxycleistantha‐12,15‐dien‐2‐one ( 1 ), was isolated from the CHCl₃‐soluble part of the EtOH extract of the pericarp of Trewia nudiflora. The structure of 1 was elucidated by means of 1D‐ and 2D‐NMR spectroscopic analyses as well as by HR‐MS. Also isolated were two known triterpenes, glutin‐5‐en‐3‐ol and olean‐18‐en‐3‐one (germanicone), as well as three known sterols, (22E,24R)‐5α,8α‐epidioxyergosta‐6,22‐dien‐3β‐ol, (22E,24R)‐5α,8α‐epidioxyergosta‐6,9(11),22‐trien‐3β‐ol, and (22E,24R)‐6‐methoxyergosta‐7,22‐dien‐3,5‐diol.     

Three New ent‐Trachylobane Diterpenoids from Co‐cultures of the Calli of Trewia nudiflora and Fusarium sp. WXE

Five diterpenoids, including three new ent‐trachylobane diterpenoids, i.e., (3α)‐3‐hydroxy‐ent‐trachylobane‐17,19‐dioic acid 19‐methyl ester ( 1 ), ent‐trachylobane‐17,19‐dioic acid 19‐methyl ester ( 2 ), ent‐trachylobane‐17,19‐dioic acid ( 3 ), and two known atisane‐type ones, i.e., (16α)‐16,17‐dihydroxy‐ent‐atisan‐19‐oic acid methyl ester ( 4 ), and 17‐hydroxy‐ent‐atisan‐19‐oic acid methyl ester ( 5 ), were isolated from the co‐culture extract of the calli of Trewia nudiflora and its endophytic fungus Fusarium sp. WXE. Their structures were elucidated by spectroscopic analyses, including 1D‐ and 2D‐NMR experiments, and HR‐Q‐TOF mass spectrometry. The antitumor and antibacterial properties of the new compounds were evaluated.     

Two New Octahydronaphthalene Derivatives from Trichoderma spirale,an Endophytic Fungus Derived from Aquilaria sinensis

Two new octahydronaphthalene derivatives, trichodermic acid A ( 1 ) and trichodermic acid B ( 2 ), along with a known analog, trichodermic acid ( 3 ), and a known modified dipeptide, trichodermamide A ( 4 ), were isolated from the extract of Trichoderma spirale, an endophytic fungus present in the medicinal plant Aquilaria sinensis. The structures of these compounds were established by extensive analysis of their spectroscopic data including 1D‐ and 2D‐NMR and MS data.     

Furanone Derivatives from Aspergillus sp. XW‐12, an Endophytic Fungus in Huperzia serrata

Two new 5‐methoxyfuran‐3(2H)‐one derivatives, huaspenone A ( 1 ) and B ( 2 ), together with four known ones, i.e., aspertetronin A ( 3 ), aspertetronin B ( 4 ), gregatin E ( 5 ), and penicilliol A ( 6 ), were isolated from the cultures of an endophytic fungus Aspergillus sp. XW‐12, derived from the stems of Huperzia serrata. The structures of the new isolates were established by detailed interpretation of the 1D‐ and 2D‐NMR and HR‐ESI‐MS data.     

Two New Secoanthraquinone Derivatives from the Marine‐Derived Endophytic Fungus Aspergillus wentii EN‐48

Two new secoanthraquinone derivatives, wentiquinones A ( 1 ) and B ( 2 ), together with the eight known compounds 3 – 10 , were isolated from the culture extracts of Aspergillus wentii EN‐48, an endophytic fungus derived from an unidentified marine brown algal species of the genus Sargassum. The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis.     

Stereoselective Total Synthesis of the Natural Oxylipin (6R,7E,9R,10S)‐6,9,10‐Trihydroxyoctadec‐7‐enoic Acid

The stereoselective total synthesis of the natural oxylipin, (6R,7E,9R,10S)‐6,9,10‐trihydroxyoctadec‐7‐enoic acid, has been accomplished using nonanal and hexane‐1,6‐diol as the starting materials. The synthesis involves Sharpless kinetic resolution, asymmetric epoxidation, and olefin cross‐metathesis as the key steps.     

Two New Citrinin Dimers from a Volcano Ash‐Derived Fungus,Penicillium citrinum HGY1‐5

Two new citrinin dimers, penidicitrinin A ((2R,3S,5aS,9R,10S,12aR,12bR)‐2,3,5a,6,9,10,12a,12b‐octahydro‐7,12a‐dihydroxy‐12b‐methoxy‐2,3,4,9,10,11‐hexamethyl‐5H‐difuro[2,3‐b : 2′,3′‐h]xanthen‐5‐one; 1 ) and penidicitrinin B ((1S,3R,4S)‐1‐{2,6‐dihydroxy‐4‐[(1S,2R)‐2‐hydroxy‐1‐methylpropyl]‐3‐methylphenyl}‐3,4‐dihydro‐3,4,5‐trimethyl‐1H‐2‐benzopyran‐6,8‐diol; 2 ), together with three known citrinin monomers were isolated from a volcano ash‐derived fungus, Penicillium citrinum HGY1‐5. Their structures were established by spectroscopic methods, and they showed no cytotoxicity against two tumor cell lines.     

Two New C20‐Diterpenoid Alkaloids from Aconitum carmichaelii

Two new C₂₀‐diterpenoid alkaloids, named aconicarchamines A and B ( 1 and 2 , resp.), were isolated from Aconitum carmichaelii. By UV, IR, MS, and 1D‐ and 2D‐NMR analyses, their structures were elucidated as 14,17‐dihydro‐14,17‐dihydroxyajabicine and 15‐O‐acetyllassiocarpine. Compound 1 is the third C₂₀‐diterpenoid alkaloid with the lycoctine skeleton bearing an exocyclic C‐atom at C(14).     

Benzodiazepine Alkaloids from Marine‐Derived Endophytic Fungus Aspergillus ochraceus

A new fungus‐derived benzodiazepine analogue, 2‐hydroxycircumdatin C ( 1 ), and a compound which has been isolated from a natural resource for the first time, but has been previously synthesized, namely (11aS)‐2,3‐dihydro‐7‐methoxy‐1H‐pyrrolo[2,1‐c][1,4]benzodiazepine‐5,11(10H,11aH)‐dione ( 2 ), along with five structurally related known alkaloids ( 3 – 7 ), were isolated from Aspergillus ochraceus, an endophytic fungus derived from the marine brown alga Sargassum kjellmanianum. Their structures were established on the basis of spectroscopic methods. The absolute configuration of 1 was determined through CD evidence. Compound 1 displayed significant DPPH radical‐scavenging activity with an IC₅₀ value of 9.9 μM , which is 8.9‐fold more potent than that of butylated hydroxytoluene (BHT), a well‐known synthetic positive control.     

Oxepine‐Containing Diketopiperazine Alkaloids from the Algal‐Derived Endophytic Fungus Paecilomyces variotii EN‐291

Two new oxepine‐containing diketopiperazine‐type alkaloids, varioloids A and B ( 1 and 2 , resp.), were isolated from the algal‐derived fungus Paecilomyces variotii EN‐291. The structures and absolute configurations were determined by detailed interpretation of 1D‐ and 2D‐NMR spectroscopic data and by analysis of acidic hydrolysates. Compounds 1 and 2 exhibited potent activity against the plant‐pathogenic fungus Fusarium graminearum with MIC values of 8 and 4 μg/ml, respectively.     

Preparation of 8‐Aza‐7‐deazaaristeromycin and ‐neplanocin A and Their 5′‐Homologs

The synthesis of new members of the aristeromycin and neplaoncin A families of carbocyclic nucleosides possessing the 1H‐pyrazolo[3,4‐d]pyrimidine ring is reported. For this purpose, an adapted route to 4‐amino‐1H‐pyrazolo[3,4‐d]pyrimidine is described.     

Two New Cytotoxic Nonsulfated Pentasaccharide Holostane (=20‐Hydroxylanostan‐18‐oic Acid γ‐Lactone) Glycosides from the Sea Cucumber Holothuria grisea

Two new lanostane‐type nonsulfated pentasaccharide triterpene glycosides, 17‐dehydroxyholothurinoside A ( 1 ) and griseaside A ( 2 ), were isolated from the sea cucumber Holothuria grisea. Their structures were elucidated by spectroscopic methods, including 2D‐NMR and MS experiments, as well as chemical evidence. Compounds 1 and 2 possess the same pentasaccharide moieties but differ slightly in their side chains of the holostane‐type triterpene aglycone. The structures of the two new glycosides were established as (3β,12α)‐22,25‐epoxy‐3‐{(O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[O‐3‐O‐methyl‐β‐D ‐glucopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranosyl‐(1→4)‐6‐deoxy‐β‐D ‐glucopyranosyl‐(1→2)]‐β‐D ‐xylopyranosyl)oxy}‐12,20‐dihydroxylanost‐9(11)‐en‐18‐oic acid γ‐lactone ( 1 ) and (3β,12α)‐3‐{(O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[O‐3‐O‐methyl‐β‐D ‐glucopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranosyl‐(1→4)‐6‐deoxy‐β‐D ‐glucopyranosyl‐(1→2)]‐β‐D ‐xylopyranosyl)oxy}‐12,20,22‐trihydroxylanost‐9(11)‐en‐18‐oic acid γ‐lactone ( 2 ). The 17‐dehydroxyholothurinoside A ( 1 ) and griseaside A ( 2 ) exhibited significant cytotoxicity against HL‐60, BEL‐7402, Molt‐4, and A‐549 cancer cell lines.     

Nigerasterols A and B,Antiproliferative Sterols from the Mangrove‐Derived Endophytic Fungus Aspergillus niger MA‐132

Two new 6,8(14),22‐hexadehydro‐5α,9α‐epidioxy‐3,15‐dihydroxy sterols, nigerasterols A and B ( 1 and 2 , resp.), together with two known cyclopentapeptides, malformins A₁ and C ( 3 and 4 , resp.), were identified in the culture extract of Aspergillus niger MA‐132, an endophytic fungus isolated from a fresh healthy sample of the mangrove plant Avicennia marina. The structures and relative configurations of these compounds were established on the basis of extensive spectroscopic analyses. The absolute configuration of compound 1 was determined by application of a modified version of Mosher's method. Nigerasterols A and B ( 1 and 2 , resp.) represent the first 5,9‐epidioxy‐sterol compounds of marine origin, and they displayed potent activity against tumor cell lines HL60 and A549 in a preliminary bioassay.     

Highly Diastereoselective Total Syntheses of (+)‐7‐Epigoniodiol, (−)‐8‐Epigoniodiol,and (+)‐9‐Deoxygoniopypyrone

An expedient concise total synthesis of (+)‐7‐epigoniodiol, (?)‐8‐epigoniodiol, and (+)‐9‐deoxygoniopypyrone is accomplished. The key transformations include a catalytic hydroxylation and base‐mediated N‐(acetyl)oxazolidinone addition reactions, which could set the consecutive OH motif that is either syn,syn or syn,anti with high diastereoselectivity. Moreover, this approach envisioned to facilitate the synthesis of other representatives of the family with structural and stereochemical variation.     

Synthesis and Crystal Structures of Two 9‐(2‐Bromoethyl)‐Substituted 7‐Deazapurines

The 7‐(2‐bromoethyl) derivatives, 2a and 2b , of 4‐chloro‐7H‐pyrrolo[2,3‐d]pyrimidine ( 1a ) and 4‐chloro‐7H‐pyrrolo[2,3‐d]pyrimidin‐2‐amine ( 1b ) were synthesized by nucleobase anion alkylation (NaH, DMF) and crystallized. X‐Ray analyses of both compounds were performed, and they revealed significantly different positioning of the side chain relative to the heterocyclic ring, depending on the substituent (H or NH₂) at C(2).     

New Pyrazolyl‐Nicotinic Acids,Methyl Esters,and 1,3,4‐Oxadiazolyl‐pyrazolyl‐pyridine Tricyclic Scaffold Derivatives from 6‐Hydrazinylnicotinic Acid Hydrazide Hydrate

This paper describes an efficient approach for the synthesis of a new series of 6‐[3‐alkyl(aryl/heteroaryl)‐5‐trifluoromethyl‐1H‐pyrazol‐1‐yl]nicotinic acids (where alkyl = CH₃; aryl = Ph, 4‐OCH₃Ph, 4,4′‐BiPh; and heteroaryl = 2‐Furyl) from the hydrolysis reaction of alkyl(aryl/heteroaryl)substituted 2‐(5‐trifluoromethyl‐5‐hydroxy‐4,5‐dihydro‐1H‐pyrazol‐1‐yl)‐5‐(5‐trifluoromethyl‐5‐hydroxy‐4,5‐dihydro‐1H‐1‐carbonylpyrazol‐1‐yl)pyridines, under basic conditions and at 70–95% yields. In a subsequent step, the esterification reaction of pyrazolyl‐nicotinic acids done in thionyl chloride and methanol led to the isolation of a series of methyl 6‐[alkyl(aryl/heteroaryl)‐5‐trifluoromethyl‐1H‐pyrazol‐1‐yl] nicotinates as stable hydrochloride salts at 64–84% yields, which could be easily converted to hydrazides to give new oxadiazolyl‐pyrazolyl‐pyridine tricyclic scaffolds at good yields from a [4 + 1] cyclocondensation reaction with 1,1,1‐triethoxyethane and 1‐(triethoxymethyl)benzene as the reagent/solvent.