Methanol → Methyl 3-bromocinnamate, predominantly trans

HRID 2393701Notes

Reaction equation

HRID 2393701 reaction equation
[Br:1][C:2]1[CH:3]=[C:4](/[CH:8]=[CH:9]/[C:10]([OH:12])=[O:11])[CH:5]=[CH:6][CH:7]=1.S(=O)(=O)(O)O.[CH3:18]O>>[Br:1][C:2]1[CH:3]=[C:4](/[CH:8]=[CH:9]/[C:10]([O:12][CH3:18])=[O:11])[CH:5]=[CH:6][CH:7]=1

Participants

4

Reactant 3

HCID 887MethanolHCID 1118Sulfuric AcidHCID 776461m-Bromocinnamic acid

Product 1

HCID 1482751Methyl 3-bromocinnamate, predominantly transYield 47%

Procedure

A solution of trans-3-(3-bromophenyl)-2-propenoic acid (0.405 mol) in methanol (300 ml) was treated with conc. sulfuric acid (6.0 ml) and heated under reflux for 10 h. The cooled mixture was filtered to afford the title compound (46.14 g, 47%) as brilliant white crystals, m.p. 53°-55° C. (Found: C, 50.10; H, 3.58; Br; 33.21. C10 H9BrO2 requires C, 49.82; H, 3.76; Br, 33.14%); νmax (nujol)/cm-1 1730.5, 1715.0, 1644; δH (270 MHz) 3.81 (3H, s, OCH3); 6.43 (1H, d, 2-H, 3J2,3 =16.2 Hz); 7.25 (1H, t, 5'-H, Jo =7.8 Hz); 7.43 (1H, dt, 4'-H, Jo =7.9, Jm =1.0 Hz); 7.50 (1H, dt, 6'-H, Jo =7.9, Jm =1.0 Hz); 7.60 (1H, d, 3-H, 3J3,2 =16.2 Hz); 7.66 (1H, t, 2'-H, Jm =1.7 Hz). δC (67.8 MHz) 51.8 (OCH3); 123.0 (3'-C); 133.0 (4'-C); 136.4 (1'-C); 143.1 (3-C); 166.9 (CO2Me). Remaining signals lie in the range 119.3-130.7 ppm; m/z 242.0, 240.0 (46.67, 47.64, M+), 211.0, 209.0 (72.69, 74.00), 182.9, 180.9 (15.67, 16.83), 161.0 (4.19), 130.0 (9.44), 102.1 (100).

Workup

  1. temperatureheated
  2. temperatureunder reflux for 10 h
  3. filtrationThe cooled mixture was filtered

Sources & evidence

ORD record
ord-fd48d88f8c394218b402d7b423434886
Source dataset
uspto-grants-1998_09
Patent number
US05807866

Reaction notes

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