Preparation of new amino derivatives of the lactone tanachin and their antimicrobial activity

Several amino derivatives have been obtained from the sesquiterpene lactone tanachin by means of the Michael reaction, and their structures have been confirmed by spectral methods. The antimicrobial activities of the compounds synthesized relative to some strains of microorganisms are considered.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 24–28, January–February, 1996. Original article submitted October 21, 1994.     

A novel strategy towards the atorvastatin lactone

We describe a novel strategy to the atorvastatin lactone based on a Paal-Knorr synthesis of pyrrole 24 by condensing diketone 23 with primary amine 22. The latter contains the syn-1,3-diol subunit and a benzyl ether function at the other end of the chain. This allowed for manipulations on the pyrrole ring via iodination at C2, metalation with t-BuLi and carboxylation. The obtained acid 26 could be converted via amide formation, debenzylation, oxidation and lactonization to atorvastatin lactone 6. The key building block, 2-((4R,6S)-6-(2-(benzyloxy)ethyl)-2,2-dimethyl-1,3-dioxan-4-yl)ethanamine (22) was obtained by two sequential asymmetric transfer hydrogenative carbonyl allylations according to Krische.     

Gracilone,a new sesquiterpene lactone from Tanacetum gracile (Tansies)

The methanolic extract of the Tanacetum gracile afforded the isolation of new sesquiterpene lactone, named gracilone (1) along with four known compounds as 14α-taraxeran-3-one (2), 14α-taraxeran-3-ol (3), apigenin (4) and β-sitosterol (5). The structure of compound 1 was elucidated on the basis of 1D, 2D NMR and MS spectroscopic analysis. Antimicrobial, antioxidant and anticancer activities of all compounds were evaluated, from which gracilone (1) showed a moderate antibacterial activity, while apigenin (4) showed comparatively more antibacterial activity against both gram­positive and gram­negative tested strains.     

Enantioselective synthesis of (S)-homocitric acid lactone and (R)-per-homocitric acid lactone involving organocatalysis

A concise enantioselective synthesis of (S)-homocitric acid lactone and its homolog, via an organocatalytic vinylogous Mukaiyama–Michael reaction of a silyloxy furan derivative and acrolein, is described.     

Pavonin: a new five-membered lactone from Adenanthera pavonina Linn. (Mimoaceae)

A new five-membered lactone named pavonin with an exo-cyclic double bond has been isolated from the methanol soluble part of Adenanthera pavonina Linn. belonging to the family Mimoaceae. The structure of pavonin has been established with the aid of spectroscopic techniques including decoupling and HMBC experiments.     

A new enantiodivergent synthesis of the Geissman-Waiss lactone

Intramolecular Michael reaction of methyl (R)-6-(tert-butoxycarbonylamino)oxy-4-hydroxy-2-hexenoate, in turn obtained from tert-butyl (R)-3-hydroxy-4-pentenoate, paved the way to the synthesis of both enantiomers of 2-oxa-6-azabicyclo[3.3.0]octan-3-one (the Geissman-Waiss lactone), a precursor for necine bases. Key intermediates in this approach were represented by enantiomeric bicyclic lactones incorporating a [1,2]-oxazinane nucleus, which has been conveniently used to install the pyrrolidine framework of the target compounds through a synthetic scheme featuring the reduction of the nitrogen-oxygen bond and an intramolecular S_N2 reaction.     

Synthesis, characterization and some properties of amide-linked porphyrin-ruthenium(II) tris(bipyridine) complexes

A new molecular dyad, comprised of a zinc-porphyrin and a ruthenium(II) tris(bipyridine) complex linked through an amide bond has been synthesized and characterized by ¹H, ¹³C NMR, UV-vis, mass-spectrometry and elemental analysis. The electrochemistry as well as the steady-state emission properties were investigated. The redox behavior of the dyad exhibits a favorable reversible characteristic. Substantial quenching of porphyrin emission was found when the Q band of 5 and 5-Zn was selectively photoexcited. This observation suggests a quenching mechanism with possible intramolecular electron transfer or energy transfer between the Ru(bpy)₃ moiety and the porphyrin free-base or Zn porphyrin moieties.     

Paludolactone: a new eudesmanolide lactone from Wedelia paludosa DC. (Acmela brasiliensis)

Phytochemical investigation of the whole plant of Wedelia paludosa (Acmela brasiliensis) furnished a new eudesmanolide lactone, named paludolactone (2), in addition to the known eudesmanolide (1), stigmasterol, kaurenoic and oleanolic acids. 1H- and 13C-NMR, and MS spectroscopic and elemental analyses were used for the structural elucidation of these compounds.     

Synthesis and structures of cooligo(lactone) macromonomers

Cooligo(lactone) macromonomers were prepared by cooligomerisation of (S,S)-3,6-dimethyl-1,4-dioxane-2,5-dione (L-lactide), 1-oxacyclohexane-2-one (δ-valerolactone) or 1-oxacycloheptane-2-one (ε-caprolactone), initiated by 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]-propane (BisGMA). Two different reaction ways were used for the synthesis: parallel reaction and step reaction of lactones and L-lactide. The macromonomers were characterised by differential scanning calorimetry (DSC), size exclusion chromatography (SEC), ¹H- and ¹³C-NMR spectroscopy and MALDI-TOF mass spectrometry. Cooligo(lactone) macromonomers prepared by parallel and by step reaction show different molecular structures resulting in different properties. Their glass transition temperatures depend on the molar ratio of lactide and lactone as well as on the degree of oligomerisation. Macromonomers with high amounts of L-lactide units are partially crystalline.     

Asymmetric synthesis of (S)-homocitric acid lactone

Starting from (S)-phenylalanine, an asymmetric synthesis of (S)-homocitric acid lactone was achieved using Seebach’s SRS methodology. An intermediate for the synthesis of the (S)-per-homocitric acid lactone has also been synthesized.     

A new strategy for folding oligo(m-phenylene ethynylenes)

Backbone-rigidified oligo(m-phenylene ethynylenes) fold into crescent or helical conformations in non-polar organic solvents.     

The isolation and structure elucidation of a new sesquiterpene lactone from the poisonous plant Coriaria japonica (Coriariaceae)

A new sesquiterpene lactone named coriarin was isolated from achenes (seeds) of Coriaria japonica (Coriariaceae) along with known constituents tutin, dihydrotutin and corianin, and its structure was deduced on a spectroscopic basis. The structure of coriarin was finally confirmed by the base-catalized chemical conversion of tutin into coriarin, in which the lactone ring linkage was transposed from C-3 to C-2. Chemical investigation of sarcocarps was also undertaken in parallel, but neither sesquiterpene lactones nor related constituents were obtained. The results indicate that sesquiterpene lactones occur only in achenes of C. japonica berry, as is the case in other Coriaria species.     

Stereoselective synthesis of a new trihydroxyindolizidine lactone

A general approach to 1,6,7-trihydroxyindolizidin-8-carboxylates is illustrated through the synthesis of a γ-lactone in an enantiopure form in seven steps starting from (3S)-3-t-butyloxy-1-pyrroline N-oxide and the acetonide of (2E,4S)-4,5-dihydroxy-2-pentenoic acid derived from (S)-malic acid and mannitol, respectively. The process was completely stereoselective and allowed the total control of the relative and absolute configuration of the five contiguous stereocentres of the product.     

A convenient new synthesis of homoserine lactone

N-trityl L-homoserine lactone is synthesised in three steps from L-aspartic acid.     

Stereoselective total synthesis of the cytotoxic lactone (−)-spicigerolide

A highly stereoselective synthesis of the naturally occurring lactone (−)-spicigerolide has been achieved utilizing OsO₄-catalyzed dihydroxylation, CBS, Lindlar’s reductions, Still-Gennari, and Grignard reactions as the key reaction steps.     

Preparation of cesium trimolybdate by the thermal decomposition of a new oxomolybdenum(VI) oxalato complex

A new molybdenum(VI) complex Cs₂(NH₄)2[Mo₃O₈(C₂O₄)₃] (CAMO) has been prepared and characterized by chemical analysis and IR spectral studies. Thermal decomposition studies have been made using TG, DTA and DTG techniques. The compound is anhydrous and stable up to 160°C. Thereafter it decomposes in three stages. The first and the second stages occur in the temperature ranges 160–220°C and 220–280°C to give the intermediate compounds having the tentative compositions Cs₄(NH₄)₂[Mo₆O₁₆(C₂O₄)₃(CO₃)₂] and Cs₄[Mo₆O₁₆(C₂O₄)₂(CO₃)₂] respectively, the later then decomposing to give the end product Cs₂Mo₃O₁₀ at 370°C. The end product was characterized by chemical analysis, IR spectral and X-ray studies.     

Degradation of oligo(lactone) branches linked to poly(methacrylate) networks

Partially resorbable composite materials were developed for bone applications and were prepared by crosslinking copolymerization of oligo(lactone) macromonomers with selected comonomers in the presence of hydroxy apatite. The composites were incubated in aqueous solution of different pH and electrolyte content over a period up to 300 days. The percentage of the released hydroxycarboxylic acid from the oligo(lactone) branches was determined by the titration or by high performance liquid chromatography (HPLC). A catalytic influence of cholesterol esterase (CE) on the hydrolysis of the materials was observed. Determination of CE activity in the presence of the different composite materials showed that the half-life time of CE was the lowest in the presence of the material undergoing the fastest degradation. After degradation the composite materials have preserved their coherence and have shown higher glass transition temperatures in the dried state than the materials before degradation.     

A new phenolic lactone from the bark of Phellodendron chinense

A new phenolic lactone,named phellolactone(1) was isolated from the bark ofPhellodendron chinense Schneid and its structure was elucidated by means of extensively spectroscopic methods,including IR,UV,HRESI-MS and NMR techniques.     

Structure of ferulidin: A new sesquiterpene lactone

Conclusions 1. From the roots ofFerula oopoda (Boiss. et Buhse) Boiss. a new sesquiterpene lactone C₁₅H₁₈O₄ with mp 170–172° C has been isolated; it has been called ferulidin.2. We have shown that ferulidin has the structure I.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 4, pp. 428–431, 1970