Guanidine Hydrochloride → 5,6-dihydrobenzo[h]quinazolin-2-amine

HRID 1400091Notes

Reaction equation

HRID 1400091 reaction equation
[CH2:1]1[CH2:11][C:9](=O)[C:8]2[C:3](=[CH:4][CH:5]=[CH:6][CH:7]=2)[CH2:2]1.C(O[CH:17]([N:21]([CH3:23])C)[N:18](C)C)(C)(C)C.Cl.[NH2:25]C(N)=N.[Na]>C(O)C>[N:25]1[C:9]2[C:8]3[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=3[CH2:2][CH2:1][C:11]=2[CH:23]=[N:21][C:17]=1[NH2:18]

Participants

6

Reactant 4

HCID 5742Guanidine Hydrochloride2×HCID 107241-TetraloneHCID 79885tert-Butoxy bis(dimethylamino)methaneHCID 5360545Sodium3×

Product 1

HCID 27634835,6-dihydrobenzo[h]quinazolin-2-amine

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

α-Tetralone (5.00 g, 34.2 mmol) was heated with t-butoxy bis(dimethylamino)methane (5.96 g, 34.2 mMol) at 90° C. overnight. The solvent was removed under vacuum to give a brown oil. The oil was dissolved in anhydrous ethanol (80 mL) and treated with guanidine hydrochloride (6.53 g, 68.4 mmol) and sodium metal (1.64 g, 71.3 mmol). After the sodium dissolved, the mixture was heated under reflux for 46 h. The mixture was cooled to ambient temperature and guanidine hydrochloride (1.00 g) and sodium metal (0.4 g) were added. Heating was then continued for 24 h. The solvent was removed under vacuum. The residue was partitioned between chloroform and water. The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was crystallized from ethanol to give 5,6-dihydrobenzo[h]quinazolin-2-amine as brown needles, 3.07 g; 1H NMR (DMSO-d6, 300 MHz) 8.08 (m, 2H), 7.24-7.40 (m, 3H), 6.40 (s, 1H), 2.81 (m, 2H), 2.68 (m, 2H) ppm; 13C-NMR (DMSO-d6, 75 MHz) 163.60, 159.09, 157.54, 140.14, 133.22, 131.02, 128.80, 127.37, 125.16, 117.15, 28.46, 23.80; MS (ES) 198 (M+H).

Workup

  1. customThe solvent was removed under vacuum
  2. customto give a brown oil
  3. temperaturethe mixture was heated
  4. temperatureunder reflux for 46 h
  5. temperatureHeating
  6. customThe solvent was removed under vacuum
  7. customThe residue was partitioned between chloroform and water
  8. dry with materialThe organic layer was dried over anhydrous sodium sulfate
  9. concentrationconcentrated under vacuum
  10. customThe residue was crystallized from ethanol

Sources & evidence

ORD record
ord-d0be8728079e465d880eb874df7d70de
Source dataset
uspto-grants-2014_12
Patent number
US08906922B2

Reaction notes

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