[N+:1]([C:4]1[CH:11]=[CH:10][CH:9]=[CH:8][C:5]=1[CH:6]=O)([O-:3])=[O:2].C(O)=O.[C:15]([OH:21])(=[O:20])[CH2:16]C(O)=O.C([O-])=O.[NH4+:25].Cl>O>[NH2:25][CH:6]([C:5]1[CH:8]=[CH:9][CH:10]=[CH:11][C:4]=1[N+:1]([O-:3])=[O:2])[CH2:16][C:15]([OH:21])=[O:20]o-Nitrobenzaldehyde (20.4 g, 0.135 mol), formic acid (20.3 mL, 0.539 mol) and malonic acid (18.3 g, 0.176 mol) were stirred at 45° C. for half an hour. Then ammonium formate (21.3 g, 0.338 mol) was added thereto, the reaction temperature was raised to 70° C. and stirred for 1 hour, and then stirred at 95° C. for another 4 hours. Then concentrated hydrochloric acid (50 mL) was added and further stirred maintaining this temperature for another 1 hour. It was cooled. 25 mL water was added, and washed twice with ethyl acetate (2×25 mL). The aqueous phase was adjusted to pH 4.2 with 50% potassium hydroxide solution. A solid precipitated. It was pumping filtered, and dried in vacuum to obtain a yellow solid 18.33 g, at a yield of 64.6%.
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