17435-72-2

Colourless Oil

ETHYL 2-(BROMOMETHYL)ACRYLATE is an intermediate used for the synthesis of aza inhibitors of chorismate mutase.

GENERAL STEPS: Phosphorus tribromide (0.51 mL, 5.4 mmol) was added slowly and dropwise to a stirred solution of ethyl 2-hydroxymethacrylate (2 g, 15.4 mmol) in ether (15 mL) at 0 °C. The reaction mixture was stirred at 0 °C for 3 h and subsequently warmed to room temperature. The reaction was quenched by the addition of water (5 mL) and the product was extracted with hexane (3 x 10 mL). The organic layers were combined, washed with brine (2 × 10 mL), dried over anhydrous MgSO4, filtered and concentrated in vacuum to afford ethyl 2-bromomethacrylate (2.4 g, 12.3 mmol, 82% yield) as a colorless liquid, which could be used in the next reaction without further purification. The product was characterized as follows: colorless oil; 1H NMR (400 MHz, CDCl3) δ 1.30 (t, J = 7.2 Hz, 3H, H6), 4.16 (s, 2H, H4), 4.24 (q, J = 7.0 Hz, 2H, H5), 5.92 (s, 1H, H1'), 6.30 (s, 1H, H1); 13C NMR ( 101 MHz, CDCl3) δ 14.1 (CH3, C6), 29.3 (CH2, C4), 61.2 (CH2, C5), 128.8 (CH2, C1), 137.6 (C, C2), 164.8 (C, C3); IR (νmax, cm-1) 1718 (C=O ester), 1628 (C=C alkene), 1182 (C-O ester), 523 (C-Br); HRMS-EI: m/z [M+H]+ calcd for C6H10BrO2: 192.9864, found: 192.6870.

If it contains some free acid, add H2O, cool, and neutralise with NaHCO3 until evolution of CO2 ceases. Extract the mixture with Et2O (3x) and dry the combined extracts (Na2SO4, 3hours). Evaporate Et2O and distil the ester collecting fraction b 39-40o/0.9mm and check spectra. [Preparation and NMR: Ramarajan et al. Org Synth Coll Vol VII 211 1990, Beilstein 2 IV 1541.]

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