Thionyl Chloride → Chromone-3-carbonyl chloride

HRID 2379415Notes

Reaction equation

HRID 2379415 reaction equation
[O:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[C:4](=[O:11])[C:3]([C:12]([OH:14])=O)=[CH:2]1.S(Cl)([Cl:17])=O>C1CCCCC1>[O:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[C:4](=[O:11])[C:3]([C:12]([Cl:17])=[O:14])=[CH:2]1

Participants

4

Reactant 2

HCID 24386Thionyl ChlorideHCID 181620Chromone-3-carboxylic acid

Product 1

HCID 15041156Chromone-3-carbonyl chloride

Reagents, catalysts & solvents 1

HCID 8078CyclohexaneSolvent

Procedure

A mixture of chromone-3-carboxylic acid (1.25 g) and thionyl chloride (6 ml) was heated at reflux for 5 minutes. The reaction mixture was then diluted with cyclohexane (15 ml) and ice-cooled. The crystalline precipitate was collected by filtration, washed with cyclohexane and dried under vacuum to give chromone-3-carbonyl chloride (1.2 g). (b) A solution of chromone-3-carbonyl chloride (1.04 g, 5 mmol) in CH2Cl2 (20 ml) was added dropwise over about 5 minutes to an ice-cooled stirred mixture of (endo)-3-aminotropane (0.7 g., 5 mmol), anhydrous K2CO3 (3 g) and CH2Cl2 (20 ml). After addition was complete, stirring was continued for a further 0.5 hour and the mixture diluted With water (50 ml). The organic phase was separated, dried (Na2SO4) and evaporated to give a solid (1.7 g). The base was dissolved in ethanol (15 ml) and acidified with ethanolic HCl to precipitate crude hydrochloride (0.9 g). Recrystallization three times from ethanol gave the title compound as pure hydrochloride (0.3 g), mp. >300° C.

Workup

  1. temperaturewas heated
  2. temperatureat reflux for 5 minutes
  3. temperaturecooled
  4. filtrationThe crystalline precipitate was collected by filtration
  5. washwashed with cyclohexane
  6. customdried under vacuum

Sources & evidence

ORD record
ord-84d371ec89444b75a5dacf1dc0604777
Source dataset
uspto-grants-1994_11
Patent number
US05362734

Reaction notes

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