Phosphorus tribromide → HCID 66905965, compound

HRID 1692181Notes

Reaction equation

[Cl:1][C:2]1[CH:3]=[C:4]([CH3:17])[C:5]([NH:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])=[C:6]([CH:10]=1)[C:7](O)=[O:8].P(Br)(Br)Br>C1(C)C=CC=CC=1>[Cl:1][C:2]1[CH:3]=[C:4]([CH3:17])[C:5]2[N:11]=[C:12]([O:14][CH2:15][CH3:16])[O:13][C:7](=[O:8])[C:6]=2[CH:10]=1

Participants

Conditions

Temperature: 65 °C

Procedure

A 1-L, three-necked flask equipped with an addition funnel, thermometer, condenser, nitrogen bubbler, and caustic scrubber was charged with 5-chloro-2-[(ethoxy-carbonyl)amino]-3-methylbenzoic acid (i.e. the product of Reference Example 1) (74.0 g, 0.288 mol) and toluene (300 mL). The mixture was heated at 60-65° C. while phosphorus tribromide (39 g, 0.144 mol) was added over about 60 minutes. The mixture was heated at 65° C. for about 30 minutes, which resulted in no more than 0.2% of the intermediate 6-chloro-2-ethoxy-8-methyl-4H-3,1-benzoxazin-4-one remaining according to HPLC analysis. The mixture was sparged with nitrogen to remove hydrogen bromide and ethyl bromide, and then cooled to 20° C. The product was collected under filtration, and the filter cake was successively washed with toluene (30 mL) and water (2×100 mL), and then suction dried. Drying the collected solid in a vacuum oven to constant weight provided the title compound (59 g, about 97% purity by HPLC analysis). A portion of the dried product was recrystallized by dissolving in N,N-dimethylformamide (4 volumes) at 60° C. and cooling to 20° C. to provide a sample of 99% purity melting at >250° C.

Workup

additionwas added over about 60 minutes

Sources & evidence

ORD record: ord-ad608d75813a4b92aa5efc462503d40b
Source dataset: uspto-grants-2012_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08153844B2

Reaction notes

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