Method for producing 2,4-dihydroxyquinoline derivatives

• US 4,904,787 A
• Filed: 04/04/1988
• Issued: 02/27/1990
• Est. Priority Date: 10/06/1986
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Chemical Industries Limited (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Kasei Corp. (Mitsubishi Chemical Group Corp.)
• Inventors: Oishi, Mari, Takuma, Yuki, Imaki, Naoshi
• Primary Examiner(s): Dixon, Jr., William R.
• Assistant Examiner(s): Sohn, Miriam
• Application Number:
  US07/177,045
• Time in Patent Office: 694 Days
• Field of Search: 546/155
• US Class Current: 546/155
• CPC Class Codes: C07D 215/22 attached in position 2 or 4

Abstract

A method for producing a 2,4-dihydroxyquinoline derivative of the formula: ##STR1## wherein each of R¹, R², R³ and R⁴ is a hydrogen atom, a lower alkyl group, a lower alkoxy group or a halogen atom, and its tautomer, which comprises cyclizing an aryl malonic acid amide ester derivative of the formula: ##STR2## wherein R¹, R², R³ and R⁴ are as defined above, and R⁵ is a lower alkyl group, by means of polyphosphoric acid.

Claims

1. A method for producing a 2,4-dihydroxyquinoline compound of the formula:

wherein each of R¹, R², R³ and R⁴ is a hydrogen atom, a lower alkyl group, a lower alkoxy group or a halogen atom, and its tautomer, which comprises cyclizing an aryl malonic acid amide ester compound of the formula;

##STR9## wherein R¹, R², R³ and R⁴ are as defined above, and R⁵ is a lower alkyl group, by means of polyphosphoric acid at a temperature of from 50°

C. to 200°

C., wherein said polyphosphoric acid is prepared in a molar ratio of P₂ O₅ /H₃ PO₄ within a range of from 0.4 to 0.6.

2. The method of claim 1, wherein said cyclizing is carried out in a solvent which is selected from the group consisting of toluene and xylene.

3. The method of claim 1, wherein said temperature is from 100°

to 150°

C.

4. The method of claim 4, wherein said polyphosphoric acid is present in an amount of from 0.1 to 50 ml relative to 1.0 g of said aryl malonic acid amide ester compound.