Phosphorus pentachloride → 4-chloro-2,2-dimethyl-3H-1,3-benzoxazine

HRID 381255Notes

Reaction equation

HRID 381255 reaction equation
[CH3:1][C:2]1([CH3:13])[NH:7][C:6](=O)[C:5]2[CH:9]=[CH:10][CH:11]=[CH:12][C:4]=2[O:3]1.P(Cl)(Cl)(Cl)(Cl)[Cl:15]>O=P(Cl)(Cl)Cl>[Cl:15][CH:6]1[C:5]2[CH:9]=[CH:10][CH:11]=[CH:12][C:4]=2[O:3][C:2]([CH3:13])([CH3:1])[NH:7]1

Participants

4

Reactant 2

HCID 24819Phosphorus pentachlorideHCID 7174282,2-dimethyl-3,4-dihydro-2H-1,3-benzoxazin-4-one

Product 1

HCID 222447204-chloro-2,2-dimethyl-3H-1,3-benzoxazine

Reagents, catalysts & solvents 1

HCID 24813Phosphorus oxychlorideSolvent

Procedure

A solution of 2,2-dimethyl-4-keto-1,3-benzoxazine (1.77 g, 10.0 mmol) and PCl5 (2.09 g, 10.0 mmol) in POCl3 (3.0 mL) was stirred at RT for 1 h then at 50-60° C. for 2 h. The reaction was concentrated and the product distilled (90-95° C./2-3 mm Hg) to afford 4-chloro-2,2-dimethyl-3H-1,3-benzoxazine. (0.496 g, 25%) as a clear oil: 1H NMR (CDCl3, 300 MHz, ppm) 7.58 (d, 1H), 7.48 (m, 1H), 6.97 (m, 1H), 6.94 (d, 1H), 1.63 (s, 6H).

Workup

  1. concentrationThe reaction was concentrated
  2. distillationthe product distilled (90-95° C./2-3 mm Hg)

Sources & evidence

ORD record
ord-ead02719994342e38f90758e4574baa7
Source dataset
uspto-grants-2001_10
Patent number
US06306840B1

Reaction notes

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