methyl 2-amino-5-methyl-3-nitrobenzoate synthesis
- Product Name:methyl 2-amino-5-methyl-3-nitrobenzoate
- CAS Number:1248541-72-1
- Molecular formula:C9H10N2O4
- Molecular Weight:210.19
Yield: 32%
Reaction Conditions:
Stage #1:5-methyl-7-nitroindoline-2,3-dione with dihydrogen peroxide;sodium hydroxide in water at 20; for 5 h;
Stage #2:methanol with toluene-4-sulfonic acid for 36 h;Reflux;
Steps:
Methyl 2-amino-5-methyl-3-nitrobenzoate (94)
Step 1.To a suspension of 91 (1.5 g, 7.4 mmol) in NaOH aq. solution (5 N, 14.0 mL) was added H2O2 aq. solution (2.0 mL). After stirred for another 5 h at room temperature, the reaction mixture acidified with 2 N conc. HCl untill pH = 4.0. The formed precipitate was filtered and dried in a vacuum oven to give a crude product for use next step without further purification.Step 2. To the solution of crude product of step 1 in methol (15.0 mL) was added p-toluenesulfonic acid hydrate (1.33 g, 7.0 mmol). The reaction mixture was refluxed for 36 h. After cooled to room temperature, the reaction mixture was concentrated under vacuum to give crude product. The crude product was chromatographed on silica gel using petroleum ether/ethyl acetate (8:1, v/v) as the eluent to give a yellow solid (500 mg, 32% for two steps);1H NMR (300 MHz, Chloroform-d) δ 8.21 (s, 1 H), 8.08 (s, 1 H), 7.71 (brs, 2 H), 3.91 (s, 3 H), 2.29 (s, 3 H); MS (ESI) 211 [M+H]+.
References:
Chen, Xuxing;Huan, Xiajuan;Liu, Qiufeng;Wang, Yuqin;He, Qian;Tan, Cun;Chen, Yi;Ding, Jian;Xu, Yechun;Miao, Zehong;Yang, Chunhao [European Journal of Medicinal Chemistry,2018,vol. 145,p. 389 - 403] Location in patent:supporting information
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