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

HRID 519204Notes

Reaction equation

HRID 519204 reaction equation
[CH2:1]([O:3][C:4](=[O:21])[CH:5]([N:7]1[C:12]2[CH:13]=[C:14]([N+:17]([O-:19])=[O:18])[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:31])=CC=1>C1(C)C=CC=CC=1>[CH2:1]([O:3][C:4](=[O:21])[CH:5]([N:7]1[C:12]2[CH:13]=[C:14]([N+:17]([O-:19])=[O:18])[CH:15]=[CH:16][C:11]=2[O:10][CH2:9][C:8]1=[S:31])[CH3:6])[CH3:2]

Participants

4

Reactant 2

HCID 87949Lawesson's reagentHCID 867276182-(6-Nitro-3-oxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester

Product 1

HCID 867276192-(6-Nitro-3-thioxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl esterYield 72%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A solution of 2-(6-nitro-3-oxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester (185.0 g, 630 mmol) and Lawesson's reagent (279.4 g, 690 mmol) in toluene (1.5 L) was heated to 120° C. for 3 h. The reaction mixture was cooled to ambient temperature and the solvent was removed in vacuo to give the crude product which was purified by chromatography on silica gel (eluting with 5% EtOAc in petroleum ether) to give 2-(6-nitro-3-thioxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester (133.0 g, 72%) as a yellow liquid. 1H NMR (CDCl3, 400 MHz): δ 8.02 (dd, J=2.4 Hz, J=8.8 Hz, 1H), 7.85 (d, J=2.4 Hz, 1H), 7.15 (d, J=8.8 Hz, 1H), 6.70 (m, 1H), 5.07 (d, J=15.2 Hz, 2H), 4.28 (q, J=7.2 Hz, 2H), 1.75 (d, J=7.6 Hz, 3H), 1.24 (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 5% EtOAc in petroleum ether)

Sources & evidence

ORD record
ord-cdc3e802f9174674963fff02385624bd
Source dataset
uspto-grants-2015_08
Patent number
US09115151B2

Reaction notes

Loading…