2-Amino-4,5-dimethoxybenzonitrile → Prazosin

HRID 1576327Notes

Reaction equation

HRID 1576327 reaction equation
[NH2:1][C:2]1[C:7]([C:8]#[N:9])=[CH:6][C:5]([O:10][CH3:11])=[C:4]([O:12][CH3:13])[CH:3]=1.C1([Li])C=CC=CC=1.[C:21]([N:23]1[CH2:28][CH2:27][N:26]([C:29]([C:31]2[O:32][CH:33]=[CH:34][CH:35]=2)=[O:30])[CH2:25][CH2:24]1)#[N:22]>C1C=CC=CC=1.C(OCC)C>[NH2:9][C:8]1[C:7]2[C:2](=[CH:3][C:4]([O:12][CH3:13])=[C:5]([O:10][CH3:11])[CH:6]=2)[N:1]=[C:21]([N:23]2[CH2:24][CH2:25][N:26]([C:29]([C:31]3[O:32][CH:33]=[CH:34][CH:35]=3)=[O:30])[CH2:27][CH2:28]2)[N:22]=1

Participants

6

Reactant 3

HCID 7359672-Amino-4,5-dimethoxybenzonitrileHCID 130593091-Cyano-4-(2-furoyl)piperazineHCID 178506676HCID 178506676, compound

Product 1

HCID 4893Prazosin

Reagents, catalysts & solvents 2

HCID 241BenzeneSolvent2×HCID 3283Diethyl EtherSolvent

Procedure

To 3.6 g. of 6-aminoveratronitrile, dissolved in 75 ml. of anhydrous benzene, a solution of phenyl lithium (prepared from 0.35 g. of lithium and 3.9 g. of bromobenzene) in 60 ml. of anhydrous diethyl ether is added under a nitrogen atmosphere. After 45 minutes 4.4 g. of 1-cyano-4-(2-furoyl)piperazine in 50 ml. of anhydrous benzene are added. The ether and part of the benzene are distilled off and 100 ml. of tetrahydrofuran are added. The mixture is refluxed under the nitrogen atmosphere for 20 hours and then decomposed with water. The liquid is distilled off and 75 ml. of water are added to the residue. The mixture is extracted with chloroform and the extract is concentrated by evaporation of the solvent. 1-(4-Amino-6,7-dimethoxy-2-quinazolinyl)4-(2-furoyl)piperazine is obtained. The product after crystallization from a mixture of ethanol and water melts at 258°-260°C.

Workup

  1. distillationThe ether and part of the benzene are distilled off
  2. additionof tetrahydrofuran are added
  3. temperatureThe mixture is refluxed under the nitrogen atmosphere for 20 hours
  4. distillationThe liquid is distilled off
  5. additionof water are added to the residue
  6. extractionThe mixture is extracted with chloroform
  7. concentrationthe extract is concentrated by evaporation of the solvent

Sources & evidence

ORD record
ord-125d9c43bad14efbb614cbf75ead5e2c
Source dataset
uspto-grants-1976_09
Patent number
US03980650

Reaction notes

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