Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 148890-63-5, name is 5-Amino-2H-benzo[b][1,4]oxazin-3(4H)-one, A new synthetic method of this compound is introduced below., category: amides-buliding-blocks
Synthesis of 3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazine-5-sulfonyl chloride Into a 500 ml 3-necked round-bottom flask, was placed a solution of 5-amino-2H-benzo[b][1,4]oxazin-3(4H)-one (5 g, 28.96 mmol, 1.00 equiv 95%) in CH3CN (300 mL). To the above was added HOAc (24.9 g) dropwise with stirring, while cooling to a temperature of 0 C. To the above was added HCl (16.2 g, 36.5%) dropwise with stirring, while cooling to a temperature of 0 C. This was followed by the addition of a solution of NaNO2 (2.52 g, 36.52 mmol, 1.20 equiv) in H2O (2 mL), which was added dropwise with stirring, while cooling to a temperature of 0 C. The resulting solution was allowed to react with stirring, for 30 min while the temperature was maintained at 0 to 5 C. in a bath of H2O/ice. This was followed by and maintained with an atmosphere of sulfur dioxide, the resulting solution was allowed to react, with stirring, for an additional 2 h while the temperature was maintained at 0–5 C. in a bath of H2O/ice. To the mixture was added CuCl2.2H2O (5.11 g, 29.97 mmol, while cooling to a temperature of 0 to 5 C. The resulting solution was allowed to react, with stirring, maintained with an atmosphere of sulfur dioxide for an additional 2 h while the temperature was maintained at 0–5 C. in a bath of H2O/ice. The resulting solution was allowed to react, with stirring, overnight while the temperature was maintained at 25 C. The reaction progress was monitored by TLC (PE:EtOAc=1:1). The reaction mixture was then quenched by the adding 200 mL of H2O/ice. The resulting solution was extracted 3 times with 300 mL of dichloromethane and the organic layers combined. The resulting mixture was washed 5 times with 200 mL of brine. The mixture was dried over MgSO4. The residue was purified by eluding through a column with a 1:15 EtOAc/PE solvent system. This resulted in 0.9 g (11%) of 3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazine-5-sulfonyl chloride as a light yellow solid. LC-MS (ES, m/z): [M+C5H11N2-Cl]+ calcd for C13H17N3O4S 312, found 312 1H NMR (CDCl3, 300 MHz, delta): 9.06(1H,s), 7.69(1H,d), 7.36(1H,m), 7.18(1H,d), 4.75(2H),s)
The synthetic route of 148890-63-5 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; MEMORY PHARMACEUTICALS CORPORATION; US2008/200471; (2008); A1;,
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