Lignans from Virola aff. pavonis leaves

Lignans, neolignans and related compounds

“…67 The lignan 48 isolated from the leaves of V. aff. pavonis 68 is an isomer of the known compound 49. 69 If correctly assigned, these compounds are stereoisomers of oleiferins A and B respectively.…”

“…Finally, compounds 183 and 184 have been isolated from the leaves of Virola aff. pavonis, 68 and 185 and 186 from the sapwood of Tsuga heterophylla (western hemlock). 135 gem-Dihalocyclopropanes have been used to synthesise the arylnaphthalene lactones justicidin E and taiwanin C (Scheme 25).…”

Asymmetric Synthesis of Natural and Unnatural Dibenzylbutane Lignans from a Common Intermediate

“…4-[(2 R ,3S,4 S )-4-(1,3-Benzodioxol-5-yl)-4-hydroxy-2,3-dimethyl-butyl]-2-methoxy-phenol ( 18 ) (7.0 mg, 0.02 mmol) was dissolved in MeCN (0.10 mL) and treated with K 2 CO 3 (5.7 mg, 2 equiv) and iodomethane (3.8 μL, 3 equiv) at 40 °C for 7 h. The mixture was diluted with DCM and filtered through a syringe filter and brought to dryness in vacuo. This material was then condensed onto silica gel and purified using the Teledyne ISCO Combi-Flash system (solid loading on silica gel, 4G column, 0–30% EtOAc, 60 CV) to afford (7 S ,8 S ,8′ R )-3′-4′-dimethoxy-3,4-methylenedioxylignan-7-ol ( 21 ) (5.4 mg, 0.015 mmol, dr > 20:1 as determined by 1 H NMR, 74.1% yield) as a clear oil: 1 H NMR (600 MHz, CDCl 3 , residual solvent peak calibrated to 7.27 ppm) δ 6.79 (m, 2H), 6.75 (d, J = 7.9 Hz, 1H), 6.73–6.71 (m, 3H), 5.95 (s, 2H), 4.31 (d, J = 9.4 Hz, 1H), 3.88 (s, 3H), 3.87 (s, 3H), 2.56 (dd, J = 12.8, 6.7 Hz, 1H), 2.50–2.43 (m, 2H), 1.82 (ddq, J = 9.5, 7.0, 2.4, 1H), 1.74 (br.s, 1H), 0.86 (d, J = 6.4 Hz, 3H), 0.58 (d, J = 7.0 Hz, 3H); 13 C­{ 1 H} NMR (150 MHz, CDCl 3 , residual solvent peak calibrated to 77.0 ppm) δ 148.7, 147.8, 147.0, 146.9, 138.3, 134.0, 120.9, 120.3, 112.2, 111.0, 107.9, 106.9, 100.9, 77.1, 55.84, 55.78, 42.8, 41.6, 33.7, 12.9, 10.0; HRMS (ESI) calcd for C 21 H 25 O 4 + [M + H]­[−H 2 O] + 341.1747, found 341.1748; [α] D 20 −54.4 ( c 0.18, CHCl 3 ); lit . [α] D 20 −57.5 ( c 0.18, CHCl 3 ).…”

“…While not a known natural product, lignan 18 is an epimer of Oleiferin-F and can be considered an unnatural derivative . Employing our previous conditions for the methylation of the free lignan phenol, we arrived at natural lignan 21 . Further derivatization of 18 can afford unnatural lignan 22 , which features a propyl group for an increased lipophilicity, a key metric in drug design …”

Nortriterpenoids and Lignans from the Fruit of Schisandra chinensis

“…This suggested that 20 is a derivative of 1,4-biphenyl-2,3-dimethylbutane-type lignan. 35) Detailed analysis of the NMR data of 20 indicated that it is an analogue of pregomisin (23). 26) In the 1 H-NMR spectra (Table 2) The relative stereochemistry of compounds 20-22 could not be determined on the basis of ROESY spectrum because the C-C bonds can rotate randomly.…”