Pyridine → Ethyl 2-(hydrazinecarboxamido)-4-methylthiazole-5-carboxylate

Temperature

0 °C

To a 2-neck round bottom flask (1 L) equipped with a mechanical stirrer was added ethyl 2-amino-4-methylthiazole-5-carboxylate (30.00 g, 161.00 mmol) in anhydrous tetrahydrofuran (750 mL) and pyridine (191.10 g, 242.00 mmol), followed by the dropwise addition of 4-nitrophenyl chloroformate (40.60 g, 202.00 mmol) in anhydrous dichloromethane (100 mL) at 0° C. The yellow reaction mixture was stirred at 0° C. for 2 h, followed by the addition of hydrazine monohydrate (25.50 g, 796.00 mmol). The resulting mixture was stirred at ambient temperature for 16 h. The yellow solid was collected by filtration and washed with cold methanol (100 mL) and diethyl ether (100 mL) to afford ethyl 2-(hydrazinecarboxamido)-4-methylthiazole-5-carboxylate as a yellow solid in quantitative yield (42.00 g): mp 225-230° C.; 1H NMR (300 MHz, DMSO-d6) δ 7.24 (br s, 4H), 4.21 (t, J=7.1 Hz, 2H), 2.48 (s, 3H), 1.26 (t, J=7.1 Hz, 3H); 13C NMR (75 MHz, DMSO-d6) δ 162.6, 156.8, 156.3, 156.3, 60.7, 17.5, 14.7; MS (ES+) m/z 245.0 (M+1).

1. customTo a 2-neck round bottom flask (1 L) equipped with a mechanical stirrer
2. stirringThe resulting mixture was stirred at ambient temperature for 16 h
3. filtrationThe yellow solid was collected by filtration
4. washwashed with cold methanol (100 mL) and diethyl ether (100 mL)

ORD record

ord-670a98da55e0428992df15a3d3cab4cd

Source dataset

uspto-grants-2011_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08049016B2