Diethyl Ether → Prazosin

HRID 461336Notes

Reaction equation

HRID 461336 reaction equation
[C:1]([N:6]1[CH2:11][CH2:10][N:9]([C:12]2[N:21]=[C:20]([NH2:22])[C:19]3[C:14](=[CH:15][C:16]([O:25][CH3:26])=[C:17]([O:23][CH3:24])[CH:18]=3)[N:13]=2)[CH2:8][CH2:7]1)(OCC)=[O:2].[CH2:27]([O:29][CH2:30][CH3:31])[CH3:28]>>[O:29]1[CH:30]=[CH:31][CH:28]=[C:27]1[C:1]([N:6]1[CH2:7][CH2:8][N:9]([C:12]2[N:21]=[C:20]([NH2:22])[C:19]3[C:14](=[CH:15][C:16]([O:25][CH3:26])=[C:17]([O:23][CH3:24])[CH:18]=3)[N:13]=2)[CH2:10][CH2:11]1)=[O:2]

Participants

3

Reactant 2

HCID 3283Diethyl EtherHCID 133706732-(4-Carbethoxypiperazin-1-yl)-4-amino-6,7-dimethoxyquinazoline

Product 1

HCID 4893Prazosin

Conditions

Temperature
-20 °C

Procedure

To the above mixture is added slowly at -20° C., 32.9 g. (0.10 mole) of 2-(4-carbethoxypiperazin-1-yl)-4-amino-6,7-dimethoxyquinazoline dissolved in 300 ml. of ethyl ether. The reaction mixture is stirred at -20° C. for 2 hours, then allowed to warm to room temperature. The resulting mixture is hydrolyzed by addition of 100 ml. of water, and the ether layer separated. The aqueous layer is extracted with 300 ml. of ether and the combined extracts are dried over anhydrous magnesium sulfate. Evaporation of solvent affords 2-[4-(2-furoyl)piperazin-1-yl]-4-amino-6,7-dimethoxyquinazoline which can be further pruified if desired by silica gel column chromatography.

Workup

  1. additionTo the above mixture is added slowly at -20° C.
  2. temperatureto warm to room temperature
  3. additionThe resulting mixture is hydrolyzed by addition of 100 ml
  4. customof water, and the ether layer separated
  5. extractionThe aqueous layer is extracted with 300 ml
  6. dry with materialof ether and the combined extracts are dried over anhydrous magnesium sulfate
  7. customEvaporation of solvent

Sources & evidence

ORD record
ord-84e6ad6aa6d945eca003f793f969127e
Source dataset
uspto-grants-1977_12
Patent number
US04062844

Reaction notes

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