Sodium Bicarbonate → Methyl 4-amino-3-(methylamino)benzoate

After dissolving 4-tert-butoxycarbonylamino-3-methylaminobenzoic acid methyl ester (794.3 mg, 2.83 mmol) in methanol (7.0 ml), a 4N hydrogen chloride-1,4-dioxane solution (3.54 ml, 14.3 mmol) was added in an ice bath, and the mixture was stirred at room temperature for 30 minutes. An equivalent amount of the 4N hydrogen chloride-1,4-dioxane solution was further added, and the mixture was stirred at 40° C. for 30 minutes. The reaction mixture was poured into ice-cooled saturated aqueous sodium bicarbonate, and was extracted with ethyl acetate (30 ml×3). The obtained organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. The residue obtained by concentration under reduced pressure was purified by silica gel column chromatography (n-hexane/ethyl acetate=4/1→3/2→1/1) to obtain 4-amino-3-methylaminobenzoic acid methyl ester. The compound was identified by LC-MS.

1. stirringthe mixture was stirred at 40° C. for 30 minutes
2. additionThe reaction mixture was poured into ice-
3. extractionwas extracted with ethyl acetate (30 ml×3)
4. washThe obtained organic layer was washed with saturated brine
5. dry with materialdried over anhydrous magnesium sulfate
6. customThe residue obtained by concentration under reduced pressure
7. customwas purified by silica gel column chromatography (n-hexane/ethyl acetate=4/1→3/2→1/1)

ORD record

ord-fb4da751d2dc4b95801a714cb887070b

Source dataset

uspto-grants-2009_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07517875B2