Synthesis of Antitumor Bicyclic Hexapeptide RA-VII Analogues Possessing an Aromatic Amino Acid at Residue 2.

RA-III acetate was treated with Lawesson's reagent to afford [Tyr-3-Ψ(CS-NH)-Ala-4]RA-III acetate. Treatment of this product with Hg(OAc)/LiCO and then methanol gave an oxazole intermediate. Acid-catalyzed arylation of the methylene carbon atom on the oxazole ring and subsequent partial hydrolysis of the oxazole ring in the resultant compounds afforded RA-VII analogues having an aromatic amino acid at residue 2.

Total Synthesis of Dinorsesquiterpenoid Oxyphyllin A/Belchinoid A.

Here, we report the first synthesis of oxyphyllin A/belchinoid A, a 7,9-seco-8,12-dinor-guaiane sesquiterpene whose isolation was reported independently by two groups in 2023. This synthesis utilizes a key sequential sulfone-mediated intermolecular alkylation/5-endo-tet cyclization reaction to establish the C1, C4, C5 stereocenters. Subsequent transformations, including regio- and stereoselective hydride addition-based desulfonylation via a π-allyl palladium complex and the Wittig reaction with a stable phosphonium ylide, facilitated the synthesis of oxyphyllin A/belchinoid A.

Synthesis of 6-Chromeno[4,3-]quinolin-7-ylphosphonates through Three Component Phosphonylation of Coumarin Carbaldehyde and Their Antimicrobial and Photophysical Properties.

Organophosphorylated coumarin derivatives were synthesized by a three-component reaction of 4-chloro-3-formylcoumarin, aromatic amines, and dialkyl phosphite in the presence of ZnCl. This process includes the formation of C(sp)-P and C(sp)-N bonds in one pot. The modular scope of the reaction allowed rapid access to a variety of 6-chromeno[4,3-]quinolin-7-ylphosphonate derivatives in good yields.

Phosphite-imidazole catalyzed -formylation and -acylation of amines.

A novel and convenient method for the -formylation reaction of amines with DMF as a formylating agent has been developed, utilizing a catalytic amount of diethyl phosphite/imidazole. Diethyl phosphite, as a nucleophilic catalyst, plays a significant role in this conversion. The presented method has a broad substrate scope, and various -formyl products were obtained in good to excellent yields.

Stereoselective synthesis of vinylphosphonates through aromatic aza-Claisen rearrangement of α-aminophosphonates.

A novel and convenient approach for the synthesis of vinyl phosphonates has been developed, utilizing an aromatic aza-Claisen rearrangement of β,γ-unsaturated α-aminophosphonates. The synthetic utility of this method was further examined in a gram-scale synthesis. The DFT calculations have provided insights into the basis of the reaction mechanism.

Analytical characterization and differentiation between threo- and erythro-4-fluoroethylphenidate.

Purpose: Methylphenidate analogs appeared on the drug market during the last years. Its analogs contain two chiral centers and, thus, have potential varying configurations (i.e.

Synthesis of 1-O-acyl- and 1-oxo-kamebanin analogues and their cytotoxic activity.

A series of 1-O-acyl- and 1-oxo-kamebanin analogues were prepared from kamebanin, isolated from Rabdosia excisa and their cytotoxicity was assayed on HL60 promyelocytic leukemia cells and HCT116 human colon cancer cells. The structure-activity relationship study showed that the presence of 1-O-acyl groups of a C-C carbon chain increased the cytotoxic activity.

Lanceolanone A, a new biflavanone, and a chalcone glucoside from the flower heads of Coreopsis lanceolata and their aldose reductase inhibitory activity and AMPK activation.

The MeOH extract of the flower heads of Coreopsis lanceolata L. (Asteraceae) exhibited aldose reductase (AR) inhibitory activity (IC 8.36 µg/mL).

Retusone A, a Guaiane-Type Sesquiterpene Dimer from and Its Inhibitory Effects on Histone Acetyltransferase HBO1 Expression.

Retusone A (), a new sesquiterpene dimer consisting of two guaiane-type sesquiterpenoids, and oleodaphnal () were isolated from heartwood of (Thymelaeaceae). The planar structure of was elucidated on the basis of HRESIMS and NMR spectroscopic data, and the relative stereochemistry was established by X-ray diffraction analysis. The absolute configuration of was determined by electronic circular dichroism.

Benzofuran and coumarin derivatives from the root of Angelica dahurica and their PPAR-γ ligand-binding activity.

A phytochemical investigation of the root of Angelica dahurica led to the isolation of benzofuran and coumarin derivatives. This is the first report of the isolation and identification of three furanocoumarin sulfates from A. dahurica root.

Reactions of Bifunctional Perfluoroarylsilanes with Activated C-F Bonds in Perfluorinated Arenes.

Reactions of bifunctional perfluoroarylsilanes, - and -CF(SiMe) as well as -BrCFSiMe, with substituted perfluoroarenes having electron-withdrawing groups were investigated using NMR and density functional theory calculation techniques. The C-F bond in perfluoroarenes was activated by the -position of an electron-withdrawing group, such as CF, CF, CN, and NO. The reaction of CF(SiMe) mainly occurred at the -position of the perfluoroarenes and also occurred at the -position of CFCN and CFNO.

[LC/Tribrid Orbitrap Analysis of Phosphodiesterase-5 Inhibitors and Their Analogs as Adulterants in Dietary Supplements].

LC/Tribrid Orbitrap was developed to determine phosphodiesterase-5 (PDE-5) inhibitors and their analogs as adulterants in dietary supplements. High-resolution MS/MS and MS spectra of PDE-5 inhibitors and their analogs were obtained by LC/Tribrid Orbitrap using both higher-energy collisional dissociation and collision-induced dissociation. We investigated dietary supplements that claim to enhance men's sexual performance, and detected PDE-5 inhibitors and their analogs.

Chemical Bonding in Polarised Push-Pull Ethylenes.

1,1-Diamino-2,2-bis(triflyl)ethylenes with both twisted and planar structures around the partial "C=C" bond were synthesised. Bonding properties in these compounds were analysed by an experimental approach using high-resolution X-ray diffraction data treated with X-ray wavefunction refinement (XWR). In the twisted compound, a dominant contribution of the charge-separated resonance structure was revealed.

Cycloartane and Oleanane Glycosides from the Tubers of .

Phytochemical analysis of the tubers of was performed as part of our continuous study on the plants of the family , which resulted in the isolation of eleven new cycloartane glycosides (⁻) and one new oleanane glycoside (), together with one known oleanane glycoside (). The structures of the new compounds were determined by extensive spectroscopic analysis, including two-dimensional (2D) NMR, and enzymatic hydrolysis followed by either X-ray crystallographic or chromatographic analysis. The aglycone () of and its C-23 epimer (), and the oleanane glycosides ( and ) showed cytotoxic activity against HL-60 leukemia cells with IC values ranging from 10.

RA-XXV and RA-XXVI, Bicyclic Hexapeptides from Rubia cordifolia L.: Structure, Synthesis, and Conformation.

Two RA-series bicyclic hexapeptides, RA-XXV (4) and RA-XXVI (5), which have no N-methyl group at Tyr-5, were isolated from the roots of Rubia cordifolia L. Their amino acid compositions and sequences were determined by interpretation of MS, and 1D and 2D NMR data and their relative structures were elucidated by XRD analysis of 4 and RA-XXVI acetate (6). The absolute stereochemistry of 4 was established by the total synthesis of 4, and that of 5, by the chemical correlation with 4.

Structural characterization of dimethyldithiodenafil and dimethylthiocarbodenafil, analogs of sildenafil.

Two analogs of sildenafil (compounds 1 and 2) were detected in three powder products acquired from online drug markets during an LC-UV-MS analysis of psychotropic drugs. Their structures were established by high-resolution mass spectrometry and NMR spectroscopy. Compound 1 was identified as 5-(5-(3,5-dimethylpiperazine-1-carbonothioyl)-2-ethoxyphenyl)-1-methyl-3-propyl-1H-pyrazolo[4,3-d]pyrimidine-7(6H)-thione and named dimethyldithiodenafil.

RA-dimer B, a New Dimeric RA-series Cyclopeptide Incorporating Two Different Types of Cycloisodityrosine Units, from Rubia cordifolia L.

RA-dimer B, a new cytotoxic RA-series peptide, was isolated from the roots of Rubia cordifolia L. Its structure was elucidated on the basis of spectroscopic analysis to be a dimeric cyclopeptide composed of deoxybouvardin and allo-RA-V. Those two cyclopeptide units are connected by an ether linkage between the phenolic oxygen atom of deoxybouvardin and the ϵa carbon atom of Tyr-6 of allo-RA-V.

Alkynyl Cinchona Catalysts affect Enantioselective Trifluoromethylation for Efavirenz under Metal-Free Conditions.

Efavirenz is manufactured worldwide, and its asymmetric synthesis requires a complex organometallic approach, while an organocatalytic approach is far less efficient. The first highly enantioselective approach is disclosed for the synthesis of Efavirenz under nonmetal organocatalysis with up to 93% ee for the Merck intermediate and 91% ee for the Lonsa intermediate using novel alkynyl cinchona catalysts.

Vetiverianines A, B, and C: Sesquiterpenoids from Vetiveria zizanioides Roots.

Three new sesquiterpenoids-vetiverianines A (1), B (2), and C (3)-and a known eudesmane sesquiterpenoid (4) were isolated from the roots of Vetiveria zizanioides. Vetiverianine A (1) has a unique carbon framework comprising a rigid tricyclic ring system. Vetiverianines B (2) and C (3) are new eremophilane sesquiterpenoids.

A New Neolignan Glycoside from Vetiveria zizanioides Roots.

A new neolignan glycoside (1) and four known aromatic compounds (2-5) were isolated. from the roots of Vetiveria zizanioides. The structure of compound 1 was determined based on spectroscopic analysis and hydrolysis.

Organogermanium compound, Ge-132, forms complexes with adrenaline, ATP and other physiological cis-diol compounds.

Background: In mammals, adrenaline and ATP are life-essential vicinal diol and cis-diol functional groups. Here, we show that interactions between a safe organogermanium compound and these cis-diol compounds have the potential to regulate physiological functions. In addition, we represent a possible new druggable target for controlling the action of cis-diol compounds.

A new bis-seco-abietane diterpenoid from Hyptis crenata Pohl ex Benth.

A new, highly oxidized, bis-seco-abietane diterpenoid named hyptisolide A (1) was isolated from Hyptis crenata Pohl ex Benth. Its structure and stereochemistry were elucidated on the basis of data obtained by HRESIMS, NMR, and X-ray diffraction analyses, and its absolute configuration was determined with vibrational circular dichroism spectroscopy. By reporter gene assay, 1 was demonstrated to induce cAMP-responsive element-dependent transcription in Neuro2A cells.

Solid-state NMR study of dopant effects on the chemical properties of Mg-, In-, and Al-doped SnP2 O7.

The effects of doped low-valence cations on the properties of the SnP2 O7 proton conductor at ambient temperature are investigated from changes in solid-state NMR spectra and nuclear magnetic relaxation times. Although the T1 H values increased with decreasing acidity as a result of cation exchange, the (1)H chemical shifts moved to lower field in Al- and In-doped materials compared with undoped ones. Furthermore, the shifts changed to higher field in Mg-doped materials, suggesting the existence of different protonic species in those materials.

Semisynthesis of salviandulin E analogues and their antitrypanosomal activity.

A series of analogues of salviandulin E, a rearranged neoclerodane diterpene originally isolated from Salvia leucantha (Lamiaceae), were prepared and their in vitro activity against Trypanosoma brucei brucei was evaluated with currently used therapeutic drugs as positive controls. One of the 19 compounds prepared and assayed in the present study, butanoyl 3,4-dihydrosalviandulin E analogue was found to be a possible candidate for an antitrypanosomal drug with fairly strong antitrypanosomal activity and lower cytotoxicity.