Lawesson's reagent → 2-(6-Bromo-3-thioxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester

HRID 519199Notes

Reaction equation

HRID 519199 reaction equation
[CH2:1]([O:3][C:4](=[O:19])[CH:5]([N:7]1[C:12]2[CH:13]=[C:14]([Br:17])[CH:15]=[CH:16][C:11]=2[O:10][CH2:9][C:8]1=O)[CH3:6])[CH3:2].COC1C=CC(P2(SP(C3C=CC(OC)=CC=3)(=S)S2)=[S:29])=CC=1>C1(C)C=CC=CC=1>[CH2:1]([O:3][C:4](=[O:19])[CH:5]([N:7]1[C:12]2[CH:13]=[C:14]([Br:17])[CH:15]=[CH:16][C:11]=2[O:10][CH2:9][C:8]1=[S:29])[CH3:6])[CH3:2]

Participants

4

Reactant 2

HCID 87949Lawesson's reagentHCID 867276162-(6-Bromo-3-oxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester

Product 1

HCID 867276172-(6-Bromo-3-thioxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl esterYield 82%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A solution of 2-(6-bromo-3-oxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester (32.5 g, 100 mmol) and Lawesson reagent (80.1 g, 200 mmol) in toluene (200 mL) was heated at 120° C. for 3 h then cooled at ambient temperature. The solvent was removed in vacuo to give the crude product, which was purified by chromatography on silica gel (eluting with 1% EtOAc in petroleum ether) to give 2-(6-bromo-3-thioxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester (28 g, 81.4 mmol, 82%) as a yellow liquid. 1H NMR (CDCl3, 400 MHz): δ 7.18 (dd, J=8.8 Hz, J=2.0 Hz, 1H), 7.01 (d, J=2.0 Hz, 1H), 6.91 (s, J=8.8 Hz, 1H), 6.54 (s, 1H), 4.90 (q, J=15.2 Hz, 2H), 4.22 (m, 2H), 1.68 (d, J=7.2 Hz, 3H), 1.16 (t, J=7.2 Hz, 3H).

Workup

  1. customThe solvent was removed in vacuo
  2. customto give the crude product, which
  3. customwas purified by chromatography on silica gel (eluting with 1% EtOAc in petroleum ether)

Sources & evidence

ORD record
ord-c7d289d96bda41c09366ca9e0c31698b
Source dataset
uspto-grants-2015_08
Patent number
US09115151B2

Reaction notes

Loading…