Reaction #3245

Reaction equation

1,2-dihydro-4-(3,4-methylenedioxyphenyl)-2-oxo-3-quinoline carboxylic acid

phosphorous oxychloride

→

title compound

Yield 59.9%

6-chloro-9,10-methylenedioxy-7H-indeno[2,1-c]quinoline-7-on

Yield 59.9%

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   Temperaturewas refluxed
2. 2
   Temperaturewith heat for 4 hours
3. 3
   workup.DISTILLATIONThe reaction mixture was distilled to dryness
4. 4
   Washwashed with n-hexane several times
5. 5
   OtherTo the residue obtained
6. 6
   Otherprecipitated
7. 7
   OtherThe crystal obtained
8. 8
   Filtrationto filter off undissolved substances
9. 9
   Otherpurified by silica gel column chromatography (eluent: chloroform)

Procedure

A mixture of 1,2-dihydro-4-(3,4-methylenedioxyphenyl)-2-oxo-3-quinoline carboxylic acid obtained in reference example 1 (10 g, 32.3 mmol) and phosphorous oxychloride (100 ml, 1.07 mol) was refluxed with heat for 4 hours. The reaction mixture was distilled to dryness and washed with n-hexane several times. To the residue obtained was added 50 g of polyphosphoric acid, and the mixture was heated at 90° C. for 2 hours. The reaction mixture was poured into ice water to filtrate a crystal precipitated. The crystal obtained was dissolved in tetrahydrofuran to filter off undissolved substances and purified by silica gel column chromatography (eluent: chloroform) to give 6.0 g (yield 59.9%) of the title compound.

Source