“…The corresponding structures were determined as 16β-acetoxyholosta-8(9), 24(25)-diene-3β-ol (1), 20, 25-epoxy-lanosta-9(11)-ene-3β-ol 18(16)–lactone (2) and 16β-acetoxyholosta-9(11), 24(25)-diene-3β-ol (3), respectively, on the basis of spectral evidence.…”
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“…[Image: see text] Medium-sized ynolides were prepared by the Lewis acid-mediated fragmentation of bicyclic γ-silyloxy-β-hydroxy-α-diazolactones in which the Cβ–Cγ bond is the ring fusion bond. Although these lactone fragmentation substrates reacted somewhat less efficiently than their carbocyclic counterparts, the fragmentation provided 11-membered ynolides in up to 84% yield. …”
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“…Cornolactone B (3) is the first natural cis-fused tricyclic dilactone iridoid containing both a five- and a six-membered lactone ring. A biosynthesis pathway is proposed for cornolactones C (4) and D (5), the C-6 epimers of compounds 1–3.…”
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“…A subsequent Mukaiyama aldol coupling allows for the incorporation of a wide array of modular two-carbon fragments. Lactone intermediates accessed via this route provide a useful platform for elaboration, as demonstrated by the preparation of a variety of C-nucleosides and fluorinated pentoses. …”
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“…The title compound, C(23)H(35)NO(2), is an amide derivative of the lactone (+)-sclareolide, and was synthesized from natural sclareol. …”
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“…In the mol­ecule of title compound, C(15)H(20)O(6), also known as cynarinin A, the cyclo­pentane ring having twist conformation and a γ-lactone ring assuming an envelope conformation are trans- and cis-fused, respectively, to a cyclo­heptane ring adopting a twist-chair conformation. …”
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“…The scope of dihydropyranone and dihydropyridinone products accessible by isothiourea‐catalyzed processes has been expanded and explored through the use of 2‐N‐tosyliminoacrylates and 2‐aroylacrylates in a Michael addition‐lactonization/lactamization cascade reaction. Notably, to ensure reproducibility it is essential to use homoanhydrides as ammonium enolate precursors with 2‐aroyl acrylates, while carboxylic acids can be used with 2‐N‐tosyliminoacrylates, delivering a range of 3,5,6‐substituted dihydropyranones and dihydropyridinones with high enantioselectivity (typically >90 % ee). …”
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“…Here, we show that the intramolecular RC reaction proceeds smoothly in the presence of 1 mol% β-ICD, and bicyclic lactones are obtained in high yields and with excellent enantiomeric excesses. …”
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“…The study on their structure–activity relationship showed that the α,β-unsaturated δ-lactone moiety, as exemplified in compounds 1 and 2, was critical to the cytotoxic activity of these compounds. …”
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“…The described synthetic pathway is completed with the chromatographic methods and the NMR analyses necessary to establish the chemical and the optical purity of the intermediates and of the final lactone.…”
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“…Moreover, four known sesquiterpene lactones 6–9 and two known bibenzyls 10, 11 were isolated from the Et(2)O extracts of Argentine Frullania brasiliensis and Radula voluta, respectively. …”
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“…Activity-guided fractionation of a MeOH extract of the roots of Saussurea lappa C.B.Clarke (Compositae), using an in vitro protein tyrosine phosphatase 1B (PTP1B) inhibition assay, led to the isolation of four active constituents: betulinic acid (1), betulinic acid methyl ester (2), mokko lactone (3) and dehydrocostuslactone (4), along with nine inactive compounds. …”
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“…One novel triterpene cycloartane-type, named hirtinone (1), six protolimonoids – nilocitin (2), dihydronilocitin B (3), melianone epimers (4) and (5), piscidinol A (6) and melianone lactone (7), one tertranortriterpenoid, hirtin (8), and one sesquiterpene, spathulenol (9), were identified in the fruits of Trichilia hirta. …”
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“…For this purpose, a specific core with functional groups capable of initiating both polymerization types is synthesized. Next, vinyl and lactone monomers are simultaneously polymerized under visible light irradiation using specific catalysts. …”
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“…This work summarizes the important studies on the reproductive effects of essential oil constituents anethole, apiole, citral, camphor, thymoquinone, trans-sabinyl acetate, methyl salicylate, thujone, pulegone, β-elemene, β-eudesmol, and costus lactone, among others.…”
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“…Compound 1 features a unique N,O-spiroketal/δ-lactone motif connected to a pyranoindole-derived bicyclo[2.2.2]diazaoctane ring. …”
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“…Two new sesquiterpenes, trichocitrinovirenes A (1) and B (2), and five known compounds including four structurally related sesquiterpenes and one γ-lactone were isolated from the soil-derived fungus Trichoderma citrinoviride PSU-SPSF346. …”
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“…The synthetic strategy is predicated on a transannular Michael reaction that provides both natural products from a common macrocyclic intermediate and leverages a diastereoselective radical cyclization to furnish a key bicyclic lactone. The latter is further advanced to a macrocyclic precursor via a Nozaki–Hiyama–Kishi cyclization and a one-pot furan oxidation/oxa-Michael cascade. …”
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“…Catalytic asymmetric dearomative [3+2] cycloaddition of α-imino γ-lactones with either 3-nitroindoles or 2-nitrobenzofurans by using a chiral copper complex as the catalyst was developed. …”
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“…The ring-opening polymerization of β-lactones into polyhydroxyalkanoates (PHA), biodegradable polymers with high molecular weight and narrow polydispersity, is of significant interest. …”
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