Compound 20

(3aR,3bS,6R,6aS,7S,8S,9aS,9bR,10R,11R,11aS)-7-((tert-Butyldimethylsilyl)oxy)-6,6a,9b,11-tetrahydroxy-8,10-dimethyl-5-methylene-11a-(prop-1-en-2-yl)tetradecahydroazuleno[5',4':3,4]benzo[1,2-d][1,3]dioxol-2-one

From: Gateway synthesis of daphnane congeners and their protein kinase C affinities and cell-growth activities

View in PubChem | MDL Molfile | ChemDraw

InChIKey NFCIJONPTZTCLU-JYWUCMQBSA-N

Compound data: CIF

Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

Activation of zinc dust: Zn dust was activated as follows: Zn dust (50 g) was added to an Erlenmeyer flask containing 1.0 N HCl (500 mL), and the heterogeneous mixture was stirred vigorously at r.t. 30 min prior to isolation by vacuum filtration. The Zn was washed with H2O (3 x 500 mL) followed by Et2O (3 x 500 mL). The resulting paste was left under high vacuum 1 h prior to being ground to a fine powder using a mortar and pestle. The powder was heated with a heat gun while under high vacuum and was left under vacuum overnight prior to use. Zn dust that had been activated as described above (35.4 mg, 0.54 mmol) and NH4Cl (5.8 mg, 0.11 mmol) were added to a microwave vial containing bis-iodide 19a (8.4 mg, 0.011 mmol). EtOH (1.1 mL, 0.01 M) was added down the sides of the vial ensuring that all solids were in rinsed into the solution. After capping, the reaction was heated to 160 °C by μ-wave for 15 min at which time the reaction was complete as determined by TLC analysis. The solvent was removed and the residue suspended in Et2O and filtered through celite. NMR of the crude reaction showed 84:16 20:19b. The residue was purified by silica gel chromatography to provide 4.4 mg desired 20 as a white solid (77%) and 1.0 mg undesired product 19b as a white solid (18%). TLC: Rf = 0.28 (30% EtOAc/petroleum ether). 1H-NMR (CDCl3, 600 MHz) δ 5.28 (brd q, 1H, J = 1.5 Hz, C16-H), 5.21 (s, 1H, C16-H), 5.19 (t, 1H, J = 1.5 Hz, C20-H), 5.07 (brd s, 1H, C20-H), 4.90 (d, 1H, J = 4.1 Hz, C14-H), 4.16 (d, 1H, J = 6.0 Hz, C3-H), 3.83 (d, 1H, J = 2.7 Hz, C12-H), 3.78 (brd d, 1H, J = 9.6 Hz, C5-H), 3.62 (s, 1H, OH), 2.99 (dd, 1H, J1 = 9.6 Hz, J2 = 4.2 Hz, C8-H), 2.80 (dd, 1H, J1 = 15.6 Hz, J2 = 9.6 Hz, C7-H), 2.51 (d, 1H, J = 15.6 Hz, C7-H), 2.43 (q, 1H, J = 7.8 Hz, C11-H), 2.26 (d, 1H, J = 9.6 Hz, C5-OH), 1.96 (dd, 1H, J1 = 13.2 Hz, J2 = 5.2 Hz, C1-H), 1.92 (s, 3H, 3 x C17-H), 1.78-1.86 (m, 3H, C2-H, C10-H, & C12-OH), 1.66 (s, 1H, OH), 1.56 (m, 1H, C1-H), 1.19 (d, 3H, J = 7.8 Hz, 3 x C18-H), 1.03 (d, 3H, J = 6.6 Hz, 3 x C19-H), 0.94 (s, 9H, Si(CH3)2(C(CH3)3)), 0.16 (s, 3H, Si(CH3)2(C(CH3)3)), 0.13 (s, 3H, Si(CH3)2(C(CH3)3)). 13C-NMR (CDCl3, 125 MHz) δ 154.2, 148.2, 143.3, 115.0, 113.6, 85.3, 82.2, 81.3, 79.2, 77.8, 72.7, 72.6, 54.8, 41.5, 40.0, 36.6, 32.9, 31.6, 25.9, 18.5, 18.3, 16.8, 14.8, -4.1, -4.6. IR (NaCl Thin Film) ν = 3468 (brd), 2947, 2930, 1790, 1462, 1377, 1258, 1065, 1023, 910, 839, 778, 732 cm-1. MS (TOF MS ES+) m/z Calculated for C27H44O8Si + Na (M+Na): 547.2703; Found: 547.2698. [α]D = 68.8 ° (c 0.50, CDCl3)