Malonic Acid → 4-Hydroxy-7-methyl-benzo[h]chromen-2-one

HRID 1727271Notes

Reaction equation

HRID 1727271 reaction equation
[CH3:1][C:2]1[CH:11]=[CH:10][CH:9]=[C:8]2[C:3]=1[CH:4]=[CH:5][CH:6]=[C:7]2[OH:12].[C:13](O)(=[O:18])[CH2:14][C:15](O)=[O:16]>>[OH:18][C:13]1[C:6]2[C:7](=[C:8]3[CH:9]=[CH:10][CH:11]=[C:2]([CH3:1])[C:3]3=[CH:4][CH:5]=2)[O:12][C:15](=[O:16])[CH:14]=1

Participants

3

Reactant 2

HCID 867Malonic AcidHCID 113556405-Methylnaphthalen-1-ol

Product 1

HCID 547180894-Hydroxy-7-methyl-benzo[h]chromen-2-oneYield 43.3%

Conditions

Temperature
75 °C

Procedure

The mixture of 5-methyl-1-naphthol (6) (1.0 g, 6.33 mmol), malonic acid (658 mg, 6.33 mmol), and PPA (10 g) was heated at 75° C. for 3 h. After the reaction, ice-water was added to the black residue. The solid was filtered, dissolved in 10% Na2CO3 solution, and stirred overnight. The basic solution was filtered, and the filtrate was acidified with 2 N HCl solution until the pH was about 4. The precipitate was then filtered and purified by silica gel chromatography to yield 7 (620 mg, 43%) as a yellow solid. mp 223-225° C.; 1H NMR (DMSO-d6) δ 2.69 (s, 3H), 5.70 (s, 1H), 7.57-7.61 (m, 2H), 7.86 (d, J=9.0 Hz, 1H), 7.92 (d, J=9.0 Hz, 1H), 8.23 (d, J=7.5 Hz, 1H), 12.8 (br s, 1H).

Workup

  1. additionwas added to the black residue
  2. filtrationThe solid was filtered
  3. dissolutiondissolved in 10% Na2CO3 solution
  4. filtrationThe basic solution was filtered
  5. filtrationThe precipitate was then filtered
  6. custompurified by silica gel chromatography

Sources & evidence

ORD record
ord-dfe75e738cab4438b04347b1c3da4580
Source dataset
uspto-grants-2009_02
Patent number
US07495026B2

Reaction notes

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