* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
With copper(l) iodide; caesium carbonate In N,N-dimethyl-formamide at 110℃; for 24 h;
1.00 g (4.97mmol) of 2-bromobenzoic acid 44, 2.00 g (9.95 mmol) of guanidine hydrochloride, 6.48 g (19.9 mmol) of cesium carbonate and 95 mg (0.497mmol) of copper(I) iodide were dissolved in 20 ml of abs. DMF and stirred at 110 °C for 24 h. The solvent was distilled off in vacuo and the residue filtered through a short pad of silica gel using methanol as eluent. After recrystallization from ethanol 717 mg (52percent) of 2-aminoquinazolone 10 were obtained as a colorless solid. Mp.: >300°C. 1H-NMR(250 MHz, DMSO-d6): / ppm = 10.95 (s, 1H, NH); 7.87 (dd,J =7.9 Hz,J =1.5 Hz, 1H, Ar-H); 7.55 (ddd,J =8.5 Hz,J =7.2 Hz,J =1.6 Hz; 1H, Ar-H); 7.19 (d,J =8.2 Hz, 1H, Ar-H); 7.09 (t,J =7.5 Hz, 1H, Ar-H); 6.34 (br, 2H, NH2). 13C-NMR(75.4 MHz, DMSO-d6): / ppm = 163.2, 152.4, 150.2, 133.9, 125.9, 123.1, 121.4, 117.1. IR: ν = 3581 (w); 3399 (m); 3147 (m); 3063 (m); 2642 (m); 1801 (w); 1689 (m); 1657 (m); 1633 (m); 1608 (s); 1575 (m); 1558 (m); 1511 (m); 1473 (s); 1451 (m); 1402 (m); 1340 (m); 1248 (m); 1166 (m); 1153 (m); 1123 (m); 1041 (m); 1018 (m); 897 (m); 785 (m); 764 (s); 716 (w); 680 (m);623 (m); 591 (m); 537 (s); 491 (m); 465 (m). Anal. calcd. for C8H7N3O*1/3H2O(167,1): C 57.50; H 4.62; N 25.15; found: C 57.65; H 4.41; N 25.30.
Reference：
[1] Applied Organometallic Chemistry, 2014, vol. 28, # 9, p. 661 - 665
[2] Synthesis, 2009, # 16, p. 2679 - 2688
[3] Bioorganic and Medicinal Chemistry Letters, 2014, vol. 24, # 24, p. 5576 - 5580
2
[ 50-01-1 ]
[ 134-20-3 ]
[ 20198-19-0 ]
Yield
Reaction Conditions
Operation in experiment
19%
With sodium methylate In methanol; water; butan-1-ol
A. Preparation of 2-amino-4-(3H)-quinazolone Guanidine hydrochloride (47.77 g, 0.5 mol) was added portionwise to a stirred suspension of sodium methoxide (32.42 g, 0.60 mol) in n-butanol (450 ml) at ambient temperature over 0.5 hour. After a further 0.5 hour a solution of methyl anthranilate (15 g, 0.10 mol) in n-butanol (150 ml) was added dropwise and then slowly brought to reflux. After distilling off ca. 100 ml of solvent the reaction mixture was heated under reflux at 116° for 117 hours. The cooled suspension was filtered, excess solvent removed and the residue dissolved in water, acidified to pH 5 and extracted with diethyl ether. The aqueous suspension was reacidified to pH 5, filtered off, washed with water and dried. The solid was then triturated in methanol, filtered, washed with ether and dried to give 2-amino-4-(3H)-quinazolone (3.0 g, 19percent) m.p. >300°.
19%
With sodium methylate In methanol; water; butan-1-ol
A. Preparation of 2-amino-4-(3H)-quinazolone Guanidine hydrochloride (47.77 g, 0.5 mol) was added portionwise to a stirred suspension of sodium methoxide (32.42 g, 0.60 mol) in n-butanol (450 ml) at ambient temperature over 0.5 hour. After a further 0.5 hour a solution of methyl anthranilate (15 g, 0.10 mol) in n-butanol (150 ml) was added dropwise and then slowly brought to reflux. After distilling off ca. 100 ml of solvent the reaction mixture was heated under reflux at 116°C for 117 hours. The cooled suspension was filtered, excess solvent removed and the residue dissolved in water, acidified to pH 5 and extracted with diethyl ether. The aqueous suspension was reacidified to pH 5, filtered off, washed with water and dried. The solid was then triturated in methanol, filtered, washed with ether and dried to give 2-amino-4-(3H)-quinazolone (3.0 g, 19percent) m.p. >300°C.
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