Thionyl Chloride → 2,3-dihydro-1,4-benzodioxine-6-carbonyl chloride

HRID 2108104Notes

Reaction equation

HRID 2108104 reaction equation
[O:1]1[C:6]2[CH:7]=[CH:8][C:9]([C:11]([OH:13])=O)=[CH:10][C:5]=2[O:4][CH2:3][CH2:2]1.S(Cl)([Cl:16])=O>C1C=CC=CC=1>[O:1]1[C:6]2[CH:7]=[CH:8][C:9]([C:11]([Cl:16])=[O:13])=[CH:10][C:5]=2[O:4][CH2:3][CH2:2]1

Participants

4

Reactant 2

HCID 24386Thionyl ChlorideHCID 27588331,4-Benzodioxane-6-carboxylic Acid

Product 1

HCID 27761682,3-dihydro-1,4-benzodioxine-6-carbonyl chloride

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

A mixture of 1,4-benzodioxane-6-carboxylic acid (0.5 g), benzene (20 ml) and thionyl chloride (5 ml) is heated for one hour under reflux. The reaction mixture is evaporated to dryness under reduced pressure. To the residue is added benzene (50 ml), then the solvent is again distilled off to leave 1,4-benzodioxane-6-carbonyl chloride. This compound dissolved in benzene (20 ml) is added dropwise, while stirring, to a mixture of 1-(3,4,5trimethoxybenzyl)piperazine dihydrochloride (1 g), triethylamine (1.5 g) and N,N-dimethylacetamide (20 ml), followed by stirring at room temperature for 30 minutes. To the reaction mixture are added water (100 ml), ethyl acetate (200 ml) and hexane (50 ml), then extraction is conducted. The extract is washed with water, dried, and concentrated under reduced pressure. The residue as purified by means of a silica gel column chromatography (hexane:acetone=1:1-2:3) to afford an oily product, which is dissolved in ethyl acetate. To the solution is added 1N hydrogen chloride - acetic acid solution (5 ml), and the mixture is left standing. The supernatant is removed by decantation, and the precipitates are recrystallized from ethyl acetate to give 1-(1,4-benzodioxan-6-ylcarbonyl)-4-(3,4,5-trimethoxybenzyl)piperazine hydrochloride (0.7 g) as colorless prisms, m.p. 180°-185° C.

Workup

  1. temperatureis heated for one hour
  2. temperatureunder reflux
  3. customThe reaction mixture is evaporated to dryness under reduced pressure
  4. additionTo the residue is added benzene (50 ml)
  5. distillationthe solvent is again distilled off

Sources & evidence

ORD record
ord-c1405817071047ddb83a4cf02a33fba2
Source dataset
uspto-grants-1990_06
Patent number
US04937246

Reaction notes

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