Modified method for preparing (1,4,5,6-tetrahydro-2-pyrimidyl)thiourea or salts thereof
A technology for thiourea and pyrimidine amine, which is applied in the improved field of preparing thiourea or its salt, can solve the problems of long reaction time, high requirements on equipment and safeguard measures, etc., achieves good product quality, improves the preparation method, and is beneficial to industrialized production Effect
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Embodiment 1
[0039] Preparation of (1,4,5,6-tetrahydro-2-pyrimidinyl)thiourea (II) hydrochloride
[0040] In a 3L three-necked flask, add (1,4,5,6-tetrahydro-2-pyrimidinyl)aminonitrile (III) 124.0g (1.0mol), thioacetamide (IV) 113.0g (1.5mol) and about 10% (g / g) hydrogen chloride / N, N-dimethylformamide solution 1000ml, react at 80-85°C to the raw material (1,4,5,6-tetrahydro-2-pyrimidinyl)aminonitrile (III) disappeared (reaction progress monitored by TLC, developer: ethyl acetate: methanol = 10:1), it took about 2 hours. After the reaction solution was cooled, it was filtered, and the filter cake was dried to obtain 182.6 g of the title compound as a white solid.
[0041] HPLC: 98.66%;
[0042] Mp: 183~185℃;
[0043] IR (KBr): 3140, 3022, 1687, 1637, 1603, 1573, 1402, 1333, 1304, 1055, 986, 961, 686cm -1 ;
Embodiment 2
[0045] Preparation of (1,4,5,6-tetrahydro-2-pyrimidinyl)thiourea (II)
[0046] In a 2L three-necked flask, add (1,4,5,6-tetrahydro-2-pyrimidinyl)thiourea (II) hydrochloride 100.0 g obtained in Example 1, 10% (g / g) of carbonic acid 750ml of sodium solution was stirred at 40-45°C for 0.5h, cooled, filtered, and the filter cake was dried to obtain 76.5g of the title compound (II) as a white solid.
[0047] HPLC: 99.25%;
[0048] Mp: 173~175℃;
[0049] IR (KBr): 3424, 3301, 3104, 3028, 2967, 2870, 1615, 1590, 1457, 1420, 1374, 1324, 1171, 1079, 905, 736, 656cm -1 ;
[0050] (+) ESI-MS: 159 (M+1).
Embodiment 3
[0052] Preparation of (1,4,5,6-tetrahydro-2-pyrimidinyl)thiourea (II)
[0053] In a 2L three-necked flask, add (1,4,5,6-tetrahydro-2-pyrimidinyl)aminonitrile (III) 124.0g (1.0mol), thioacetamide (IV) 90.0g (1.2mol) and Saturated hydrogen chloride / tetrahydrofuran solution 1000ml, react at 45-50°C until the raw material (1,4,5,6-tetrahydro-2-pyrimidinyl)aminonitrile (III) disappears (TLC monitors the reaction progress, developer: acetic acid Ethyl ester: methanol = 10: 1), it takes about 4h. Add about 20% (g / g) sodium hydroxide aqueous solution to adjust the pH of the reaction solution to about 8, filter, and dry the filter cake to obtain 143.5 g of the title compound (II) as a white solid.
[0054] HPLC: 98.30%;
[0055] Mp: 172~174℃;
[0056] IR (KBr): 3425, 3301, 3105, 3028, 2967, 2870, 1618, 1591, 1458, 1422, 1374, 1323, 1172, 1078, 905, 735, 657cm -1 ;
[0057] 1 H NMR (400MHz, CDCl 3 ) δ (ppm): 1.97 ~ 2.03 (2H, quintet), 3.43 ~ 3.46 (4H, t);
[0058] (+) ESI-MS: 15...
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