Hydrochloric Acid → HCID 11138191, compound

Participants

Reaction Steps

A solution of 69.0 g (234 mmol) of methyl 4-allyl-2-(ethoxycarbonylmethoxy)phenoxyacetate was added dropwise in the course of 2.5 h to a suspension of 12.0 g (500 mmol) of sodium hydride in 500 ml of tetrahydrofuran. The reaction mixture was then refluxed for 20 h and, after cooling, poured into 1.51 of ice water. The resultant mixture was acidified to pH 2 with 2N hydrochloric acid and extracted three times, each time with 2 l of ether. The combined ether extracts were dried over sodium sulfate, freed from solvent on a rotary evaporator and taken up into 400 ml of ethanol. 400 ml of 2N hydrochloric acid were added and the mixture was refluxed for 20 h. The mixture was then poured into 1.5 l of ice water, the product was extracted four times, each time with 1.5 l of ether, and the combined ether extracts were washed with 1 l of water and 100 ml of saturated sodium chloride solution. After drying over sodium sulfate, concentration on a rotary evaporator and flash chromatography (pentane/ether, 4:1, Rf=0.37) on silica gel, 20.0 g (42%) of 7-allylbenzo[b][1,4]dioxepin-3-one (1) were obtained as a colorless liquid. Odor: linear, very intensive marine-floral odor with nuances of ozone, watermelons and fatty aldehydes. -IR (film): ν=1502/1581/1436/1639 cm−1 (ν C═C, Ar), 1742 cm−1 (ν C═O), 1267/1305 cm−1 (ν ring), 1051 cm−1 (ν C—O—C). -1H-NMR (CDCl3): δ=3.30 (d, J=6.8 Hz, 2H, 1′-H2), 4.68 (d, J=7.2 Hz, 2-, 4-H2) 5.05-5.10 (m, 2H, 3′-H2), 5.92 (mc, 1H, 2′-H), 6.77-6.93 (m, 3H, 6-, 8-, 9-H). -13C-NMR (CDCl3): δ=39.15 (t, C-1′), 75.41/75.63 (2t, C-2,-4), 116.00 (t, C-3′), 120.67/120.73 (2d, C-6,-9), 123.73 (d, C-8), 135.94 (s, C-7), 136.88 (d, C-2′), 146.46 (s, C-9a), 148.00 (s, C-5a), 204.61 (s, C-3). -MS (EI): m/z (%)=91 (97) [C7H7+], 120 (25) [C7H4O2+], 161 (13) [M+-C2H3O], 175 (6) [M+-CHO], 204 (100) [M+].

Provenance & Evidence