benzofurans and tetrahydrofuran

Myristica fragrans Houtt., the source of very important spice 'nutmeg' used world over is native to India, Indonesia, Sri Lanka, South Africa and Southeast Asia. Phytochemical investigation of M. fragrans stem bark led to the isolation of bis-aryl dimethyl tetrahydrofuran lignans, such as grandisin [(7S,8S,7'S,8'S)-3,3',4,4',5,5'-hexamethoxy-7,7',8,8'-lignan] and (7S,8S,7'R,8'R)-3,3',4,4',5,5'-hexamethoxy-7,7',8,8'-lignan along with important lignans and neolignans, licarinA, licarin B, odoratisol A, (2S, 3R)-7-methoxy-3-methyl-5-((E)-prop-1-enyl)-2-(5-methoxy,3,4-methylenedioxyphenyl)-2,3-dihydrobenzofuran, elemicin, fragransin B

Topics: Anisoles; Benzofurans; Dioxoles; Furans; India; Indonesia; Lignans; Molecular Structure; Myristica; Phytochemicals; Plant Bark; Spectrum Analysis; Sri Lanka

A phytochemical investigation of the EtOH extract from the aerial parts of Viburnum betulifolium Batal. afforded four new tetrahydrofuran lignans, betulifolium A-D (1, 2, 4, and 5), together with two known compounds vibsanol-9'-al (3) and sarcomeginal (6). This paper deals with the isolation and structure elucidation of the new compounds on the basis of spectroscopic methods, including 1D NMR, 2D NMR analyses and HR-ESI-MS data.

Topics: Benzofurans; Diterpenes; Drugs, Chinese Herbal; Furans; Lignans; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Viburnum

The diastereo- and enantioselective synthesis of 2,3-disubstituted trans-2,3-dihydrobenzofuran derivatives (15 examples, up to 96 : 4 dr, 95 : 5 er) via intramolecular Michael addition has been developed using keto-enone substrates and a bifunctional tertiary amine-thiourea catalyst. This methodology was extended to include non-activated ketone pro-nucleophiles for the synthesis of 2,3-disubstituted indane and 3,4-disubstituted tetrahydrofuran derivatives.

Topics: Amines; Benzofurans; Catalysis; Chemistry Techniques, Synthetic; Furans; Ketones; Molecular Structure; Solvents; Stereoisomerism; Temperature; Thiourea

A new tetramer oligostilbenoid possessing tetrahydrofuran ring, malaysianol C (1), was isolated from the acetone extract of the stem bark of Dryobalanops lanceolata, together with four known oligostilbenoids nepalensinol E (2), ϵ-viniferin (3), laevifonol (4), and ampelopsin F (5). The structures of isolated compounds were elucidated on the basis of spectral evidence. The antibacterial activity of the isolated compounds was evaluated using resazurin microtitre-plate assay, whereas the cytotoxic activity was tested using MTT assay. The plausible biogenetic routes of the isolated compounds are also discussed.

Topics: Anti-Bacterial Agents; Antineoplastic Agents, Phytogenic; Benzofurans; Dipterocarpaceae; Flavonoids; Furans; Humans; Malaysia; Molecular Structure; Plant Bark; Plant Extracts; Plant Stems; Stereoisomerism; Stilbenes

Fifteen new lignans, gymnothelignans A-O (1-15), bearing tetrahydrofuran with variable conformations belonging to three potentially related skeletons were isolated from Gymnotheca chinensis Decne. The structures were elucidated by means of detailed spectroscopic analysis. Absolute configurations were assigned using X-ray single-crystal diffraction and chemical transformations. Moreover, by the homology, compounds 1-11 and eupomatilones were confirmed to have uniform R-configuration at C-5. However, a synthesized congener has long been mistaken as 5-epimer of eupomatilone-6. This work provides guidance for the absolute configuration establishment of the subeupomatilone family with trans-H-4-H-5 configuration.

Topics: Benzofurans; Biological Products; Crystallography, X-Ray; Furans; Lignans; Magnetic Resonance Spectroscopy; Molecular Conformation; Molecular Structure; Stereoisomerism

Novozyme 435 could be a highly efficient catalyst in the asymmetric acylation of (R,S)-3-n-butylphthalide in tetrahydrofuran-hexane solvents. The effect of various reaction parameters such as agitation velocity, water content, mixed media, temperature, concentration of Novozyme 435, molar ratio of acetic anhydride to (R,S)-3-n-butylphthalide, reaction time, enantiomeric excess of substrate (ee(S)), enantiomeric excess of product (ee(P)), and enantioselective ratio (E) were studied. Tetrahydrofuran markedly improved (R,S)-3-n-butylphthalide conversion, enantiomeric excess of remaining 3-n-butylphthalide, and enantiomeric ratio. The optimum media were 50% (v/v) tetrahydrofuran and 50% (v/v) hexane. Other ideal reaction conditions were an agitation velocity of 150 rpm, 0.4% (v/v) water content, temperature of 30 °C, 8 mg/mL dosage of Novozyme 435, 8:1 (0.4 mmol: 0.05 mmol) molar ratio of acetic anhydride to (R,S)-3-n-butylphthalide, and a reaction time of 48 hr. Under the optimum conditions, 96.4% ee(S) and 49.3% conversion of (R,S)-3-n-butylphthalide were achieved. In addition, enantiomeric excess of the product was above 98.0%.

Topics: Acylation; Benzofurans; Candida; Catalysis; Enzymes, Immobilized; Fungal Proteins; Furans; Lipase; Water

New synthesis approaches that have led to a series of novel tetrahydrodibenzo[b,f]furo[2,3-d]oxepine derivatives are described. A systematic synthetic approach for the introduction of small carbon substituents (methyl groups) around the tetrahydrofuran moiety of tetrahydrodibenzo[b,f]furo[2,3-d]oxepine derivatives is reported. Preliminary pharmacological data of the newly synthesised compounds are also communicated.

Topics: Anti-Anxiety Agents; Benzofurans; Binding Sites; Furans; Oxepins; Stereoisomerism; Structure-Activity Relationship