Phosphoric Acid → 3-bromo-7-iodo-5H-chromeno[2,3-b]pyridin-5-one

HRID 931541Notes

Reaction equation

HRID 931541 reaction equation
OP(O)(O)=O.[Br:6][C:7]1[CH:8]=[N:9][C:10]([O:16][C:17]2[CH:22]=[CH:21][C:20]([I:23])=[CH:19][CH:18]=2)=[C:11]([CH:15]=1)[C:12]([OH:14])=O>O>[Br:6][C:7]1[CH:15]=[C:11]2[C:12](=[O:14])[C:22]3[C:17](=[CH:18][CH:19]=[C:20]([I:23])[CH:21]=3)[O:16][C:10]2=[N:9][CH:8]=1

Participants

4

Reactant 2

HCID 1004Phosphoric AcidHCID 574756375-Bromo-2-(4-iodophenoxy)nicotinic acid

Product 1

HCID 574756483-bromo-7-iodo-5H-chromeno[2,3-b]pyridin-5-oneYield 85.3%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
117.5 °C

Procedure

A 5 L 3-neck flask equipped with an overhead stirrer, a thermometer and nitrogen inlet was charged with PPA (4 Kg, 1942 mL) (115% H3PO4) and heated to 115-120° C. 5-Bromo-2-(4-iodophenoxy)nicotinic acid (400 g, 952 mmol) was charged portion wise to the hot PPA. The viscous mixture was then allowed to stir overnight (16-18 h) at 115-120° C. The dark viscous mixture was cooled to 60-65° C. and poured slowly onto a mixture of ice (3000 g) and water (2000 mL) under mechanical stirring. The light brown slurry was allowed to stir overnight and filtered at RT. The wet cake was washed with water (2×1000 mL) followed by IPA (1500 mL) and hexane (2×1000 mL). The solid was dried to obtain 326.4 g of 3-Bromo-7-iodo-5H-chromeno[2,3-b]pyridine-5-one as a grey solid.

Workup

  1. customA 5 L 3-neck flask equipped with an overhead stirrer
  2. temperatureThe dark viscous mixture was cooled to 60-65° C.
  3. stirringto stir overnight
  4. filtrationfiltered at RT
  5. washThe wet cake was washed with water (2×1000 mL)
  6. customThe solid was dried

Sources & evidence

ORD record
ord-5a8694ddc95b481ca88a55662daba587
Source dataset
uspto-grants-2016_03
Patent number
US09296759B2

Reaction notes

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