Bromide ion → HCID 67604791, compound

Participants

Reaction Steps

A 2.16 g (90 mmol) portion of magnesium turnings was stirred vigorously under nitrogen with a Teflon coated magnetic stir bar for 16 h. A crystal of iodine and 10 mL of dry THF were added. About 10% of 10 mL of 2-(2-bromoethyl)-1,3-dioxolane was added. An exothermic reaction occurred. The mixture was diluted with an additional 90 mL of THF and the remaining 90% of the bromide was added dropwise over 45 min, The mixture was stirred for a further 3 h at room temperature and added dropwise over 20 min to an ice-cold solution of 18.48 g (77.3 mmol) of 1-nitro-2-(2,3,4-trimethoxyphenyl)ethene in 100 mL of THF. The cooling bath was removed, the mixture was stirred at room temperature for 20 h, poured into 500 mL of ice cold 3% aqueous HCl and extracted with three 200 mL portions of ether. The combined ether extracts were washed with 200 mL of saturated aqueous NaHCO3 and 200 mL of brine and dried over MgSO4. Removal of the solvent in vacuo left 17.14 g of an orange oil. This material was purified by flash chromatography on a column of 100 g of silica gel eluted successively with 250 mL portions of 0, 10, 20, 30, 40, 50, 60, 70, 80 and 100% ether in hexanes and 75 mL fractions were collected. Fractions 23-27 were combined and evaporated in vacuo to afford 5.53 g of 1,1-ethylenedioxy-5-nitro-4-(2,3,4-trimethoxyphenyl)pentane as an oil. 1H NMR (CDCl3) -- 1.5-1.9 (m, 4H), 3.7-4.0 (1 m, 14H), 4.6 (m, 2H), 4.85 (m, 1H), 6.6 (d, 1H), 6.8 (d, 1H).

Provenance & Evidence