Topical antiinflammatory dehydroabietylamine derivatives. IV

Copper-Catalyzed Fluoroamide-Directed Remote Benzylic C-H Olefination: Facile Access to Internal Alkenes

A general, site-selective copper-catalyzed fluoroamide-directed remote benzylic C-H olefination of N-fluoroamides with terminal alkenes for producing internal alkenes is disclosed. This protocol proceeds via a hybrid Cu-radical mechanism, which synergistically...

Syntheses of C-ring modified dehydroabietylamides and their cytotoxic activity

Due to their auspicious pharmacological efficacy as future drug candidates, natural products have been attracting scientific interest for centuries. An interesting field of research concerns the natural product class of terpenes. In this regard, a multitude of studies have already shown their promising biological potential. Therefore, a set of 27 derivatives of the diterpene dehydroabietylamine was synthesized, focusing on C-ring modifications and the derivatization of the amino moiety at C-18. Subsequent screening of the compounds in colorimetric sulforhodamine B-assays revealed an in vitro cytotoxicity especially towards malignant cell line MCF7. Particularly, 12-hydroxy-N-(isonicotinoyl)dehydroabietylamine and N-(4-methoxybenzoyl)dehydroabietylamine showed good cytotoxic activities (EC₅₀ (MCF7) = 4.3 ± 0.2 μM and EC₅₀ (MCF7) = 4.5 ± 1.5 μM, respectively) and significant selectivities (SI = 6.2 and SI = 8.8, respectively) towards malignant cell lines.

Synthesis and antitumor activities of piperazine- and cyclen-conjugated dehydroabietylamine derivatives

A series of piperazine- and cyclen-conjugated dehydroabietylamine derivatives were synthesized and characterized by 1H NMR, 13C NMR, and HRMS. The in vitro antitumor activities of conjugates 10–13 against MCF-7 and HepG-2 tumor cell lines were evaluated using CCK-8 assay. The results show that the synthesized compounds cause a dose-dependent inhibition of cell proliferation and display different antitumor activities with the IC50 values ranging from 23.56 to 78.92 μm. Moreover, the antitumor activity of conjugate 10 against the MCF-7 cell line is superior to that of the positive control 5-fluorouracil. In addition, flow cytometric assay revealed that the representative conjugate 10 could induce apoptosis in MCF-7 tumor cells in a dose-dependent manner.

Stereoselective cathodic synthesis of 8-substituted (1R,3R,4S)-menthylamines

The electrochemical generation of menthylamines from the corresponding menthone oximes equipped with an additional substituent in position 8 is described. Due to 1,3-diaxial interactions a pronounced diastereoselectivity for the menthylamines is found.

Synthetic derivatives of aromatic abietane diterpenoids and their biological activities

Naturally occurring aromatic abietane diterpenoids (dehydroabietanes) exhibit a wide range of biological activities. A number of synthetic studies aimed at modifying the abietane skeleton in order to obtain new potential chemotherapeutic agents have been reported. In this study, the biological activities of synthetic derivatives of aromatic abietane diterpenoids are reviewed.

Dehydroabietylamine derivatives as multifunctional agents for the treatment of Alzheimer's disease

Dehydroabietylamine derivatives were found to show activity against Alzheimer's disease. Compound3b, in particular, showed potent multifunctional activity for the treatment of Alzheimer's disease.

Metal-free oxidation of aromatic carbon-hydrogen bonds through a reverse-rebound mechanism

Methods for carbon-hydrogen (C-H) bond oxidation have a fundamental role in synthetic organic chemistry, providing functionality that is required in the final target molecule or facilitating subsequent chemical transformations. Several approaches to oxidizing aliphatic C-H bonds have been described, drastically simplifying the synthesis of complex molecules. However, the selective oxidation of aromatic C-H bonds under mild conditions, especially in the context of substituted arenes with diverse functional groups, remains a challenge. The direct hydroxylation of arenes was initially achieved through the use of strong Brønsted or Lewis acids to mediate electrophilic aromatic substitution reactions with super-stoichiometric equivalents of oxidants, significantly limiting the scope of the reaction. Because the products of these reactions are more reactive than the starting materials, over-oxidation is frequently a competitive process. Transition-metal-catalysed C-H oxidation of arenes with or without directing groups has been developed, improving on the acid-mediated process; however, precious metals are required. Here we demonstrate that phthaloyl peroxide functions as a selective oxidant for the transformation of arenes to phenols under mild conditions. Although the reaction proceeds through a radical mechanism, aromatic C-H bonds are selectively oxidized in preference to activated Csp3-H bonds. Notably, a wide array of functional groups are compatible with this reaction, and this method is therefore well suited for late-stage transformations of advanced synthetic intermediates. Quantum mechanical calculations indicate that this transformation proceeds through a novel addition-abstraction mechanism, a kind of 'reverse-rebound' mechanism as distinct from the common oxygen-rebound mechanism observed for metal-oxo oxidants. These calculations also identify the origins of the experimentally observed aryl selectivity.

Synthesis and NMR Spectral Studies of the 7-C60-Adduct of N,N-(Tetrachlorophthaloyl) Dehydroabietylamine

The 7-C₆₀-adduct of N,N-(tetrachlorophthaloyl)dehydroabietylamine was synthesized for the first time and characterized by IR, UV-vis, mass and NMR spectral studies. The ¹H-NMR and ¹³C-NMR resonance signals of the new compound are unambiguously assigned by using homo- and heteronuclear 2D NMR spectroscopic techniques such as COSY, ROESY, HSQC and HMBC. The C₁ symmetric structure with 6,6-junction of compound was determined.

Cytotoxic effects and pro-apoptotic mechanism of TBIDOM, a novel dehydroabietylamine derivative, on human hepatocellular carcinoma SMMC-7721 cells

We have investigated the antiproliferative effects of TBIDOM (N-(4-(2,2,2-trifluoroethyl) benzylidene) (7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthren-1-yl) meth-anamine) and have explored its possible mechanisms on human hepatocellular carcinoma SMMC-7721 cells. The proliferative status of cells treated with TBIDOM was measured by the colorimetric MTT assay. Cellular apoptosis was analysed using Hoechst 33342 staining and flow cytometry. Reduction of mitochondrial membrane potential (Δψm) was also detected by flow cytometry. Western blotting assay was used to evaluate the release of cytochrome c and expression of p53, Bcl-2 and Bax proteins. It was shown that TBIDOM displayed a significant inhibitory effect on growth of SMMC-7721 cells in a dose- and time-dependent manner. Hoechst 33342 staining and flow cytometry analysis showed an increase of apoptosis rate and decrease of mitochondrial membrane potential after SMMC-7721 cells were exposed to TBIDOM for 24 h. Pretreatment of SMMC-7721 cells with TBIDOM significantly induced a decrease of Bcl-2 protein expression and an increase of caspase-3 activity and Bax protein expression. The results indicated that TBIDOM could effectively inhibit proliferation by induction of apoptosis and could be a promising candidate in the development of a novel class of antitumour agent.

N-Benzylidenenordehydroabietylamine

The title compound [systematic name: (1R,4aS,10aR,E)-N-benzyl­idene-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octa­hydro­phenanthren-1-amine], C₂₆H₃₃N, has been synthesized from nor-dehydro­abietylamine and benzaldehyde. The two cyclo­hexane rings form a trans ring junction with classic chair and half-chair conformations, respectively, the two methyl groups are on the same side of tricyclic hydro­phenanthrene structure. The dihedral angle between two benzene rings is 44.2 (4)°. The C=N bond is in an E configuration.

(E)-(4-Chloro-benzyl-idene){[(1R,4aS,10aR)-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octa-hydro-1-phenanthryl]-methyl}amine

The title compound, C₂₇H₃₄ClN, has been synthesized from 4-chloro­benzaldehyde and dehydro­abietylamine. There are two unique mol­ecules in the unit cell. Each mol­ecule has three chiral centres, which exhibit R, S and R absolute configurations. The two cyclo­hexane rings form a trans ring junction with classical chair and half-chair conformations.