Phosphorus oxychloride → Methyl 2,6-dichlorobenzoxazole-4-carboxylate

HRID 249826Notes

Reaction equation

[Cl:1][C:2]1[CH:3]=[C:4]2[O:8][C:7](=S)[NH:6][C:5]2=[C:10]([C:12]([O:14][CH3:15])=[O:13])[CH:11]=1.O=P(Cl)(Cl)[Cl:18].P(Cl)(Cl)(Cl)(Cl)Cl>>[Cl:18][C:7]1[O:8][C:4]2[C:5](=[C:10]([C:12]([O:14][CH3:15])=[O:13])[CH:11]=[C:2]([Cl:1])[CH:3]=2)[N:6]=1

Participants

Reactant 3

HCID 24813Phosphorus oxychloride

HCID 24819Phosphorus pentachloride

HCID 58085840Methyl 6-chloro-2-thioxo-2,3-dihydrobenzoxazole-4-carboxylate

Product 1

HCID 58085877Methyl 2,6-dichlorobenzoxazole-4-carboxylateYield 99.1%

Conditions

Temperature: 125 °C

Procedure

A mixture of the product from Step A (2.00 g, 8.20 mmol), POCl3 (1.26 g, 8.21 mmol), and PCl5 (1.71 g, 8.21 mmol) was heated to 125° C. for 2.5 hours. The reaction mixture was dried under high vacuum for 24 hours to afford methyl 2,6-dichlorobenzoxazole-4-carboxylate (2.00 g, 99%) as a brown solid: 1H NMR (300 MHz, CDCl3) δ 8.04 (d, J=2.0 Hz, 1H), 7.72 (d, J=2.0 Hz, 1H), 4.04 (s, 3H); MS (ESI+) m/z 247 (M+H).

Workup

customThe reaction mixture was dried under high vacuum for 24 hours

Sources & evidence

ORD record: ord-2485c042f8754c1c994b4a527a39b4c2
Source dataset: uspto-grants-2011_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07863271B2

Reaction notes

Loading…