Methanol → Pirquinozol

HRID 1763493Notes

Reaction equation

HRID 1763493 reaction equation
C([O:3][C:4]([C:6]1[CH:18]=[C:17]2[N:8]([C:9](=[O:19])[NH:10][C:11]3[CH:12]=[CH:13][CH:14]=[CH:15][C:16]=32)[N:7]=1)=O)C.[H-].C([Al+]CC(C)C)C(C)C.CO>O1CCCC1.CCCCCC>[OH:3][CH2:4][C:6]1[CH:18]=[C:17]2[N:8]([C:9](=[O:19])[NH:10][C:11]3[CH:12]=[CH:13][CH:14]=[CH:15][C:16]=32)[N:7]=1

Participants

6

Reactant 3

HCID 887MethanolHCID 21225700DiisobutylaluminumhydrideHCID 1360233445,6-Dihydro-5-oxopyrazolo[1,5-c]quinazoline-2-carboxylic acid ethyl ester

Product 1

HCID 135449340PirquinozolYield 99.1%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 8058HexaneSolvent

Procedure

A suspension of 3.84 g (0.015 mole) of 5,6-dihydro-5-oxopyrazolo[1,5-c]quinazoline-2-carboxylic acid ethyl ester prepared as described in part A above is stirred in 150 ml of tetrahydrofuran under nitrogen at room temperature. There is added 24 ml (0.034 mole) of a 20% solution of diisobutyl aluminum hydride in hexane. The resultant solution is stirred for 1 hour at room temperature whereupon 50 ml of methanol is added and the reaction mixture refluxed for 1 hour. The precipitate of aluminum alkoxide is filtered, air dried and Soxhlet extracted for 48 hours with boiling methanol. The extract is combined with the above filtrate and stripped to give 3.2 g of a white solid (quantitative yield). Recrystallization from methanol gives 2.7 g of pure title compound, m.p. 285°-287°.

Workup

  1. customprepared
  2. additionis added
  3. temperaturethe reaction mixture refluxed for 1 hour
  4. filtrationThe precipitate of aluminum alkoxide is filtered
  5. customair dried
  6. extractionSoxhlet extracted for 48 hours with boiling methanol

Sources & evidence

ORD record
ord-b3f4225059fb4dc0a11d16bc985e2345
Source dataset
uspto-grants-1978_09
Patent number
US04112096

Reaction notes

Loading…