[S:1]1[C:5]2[CH:6]=[C:7]([CH2:10][C:11](O)=O)[CH:8]=[CH:9][C:4]=2[N:3]=[CH:2]1.[Cl:14][C:15]1[N:20]=[N:19][C:18]([NH:21][NH2:22])=[CH:17][CH:16]=1.Cl.CN(C)CCCN=C=NCC.O.OC1C2N=NNC=2C=CC=1.C(=O)([O-])[O-].[K+].[K+]>CN(C)C=O.ClCCl.C(O)(=O)C>[S:1]1[C:5]2[CH:6]=[C:7]([CH2:10][C:11]3[N:19]4[N:20]=[C:15]([Cl:14])[CH:16]=[CH:17][C:18]4=[N:21][N:22]=3)[CH:8]=[CH:9][C:4]=2[N:3]=[CH:2]1Benzothiazol-6-yl-acetic acid (44 g, 228 mmoles) and (6-chloro-pyridazin-3-yl)-hydrazine (36.2 g, 251 mmoles) were dissolved in a mixture of anhydrous dimethylformamide (40 mL) and anhydrous dichloromethane (600 ml). The mixture was under nitrogen and cooled to 0° C. in an ice bath, then N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (65.5 g, 342 mmoles), hydroxybenzotriazole hydrate (38.4 g, 251 mmoles) and potassium carbonate (157 g, 1.14 moles) was added into the mixture. The mixture was stirred at 5° C. for 4 h and at room temperature overnight. TLC showed that the SM disappeared. The mixture was filtered and the filtrate was washed with brine (400 mL×2). The organic phase was dried over anhydrous Na2SO4, concentrated to obtain a brown oil. The oil was dissolved in acetic acid (750 mL) and stirred at 50° C. for 4 hours. After such time the solvent was removed in vacuo and the residue was purified by a silica gel column eluting with ethyl acetate to obtain crude product (20 g). The crude product was recrystallized from ethyl acetate and petroleum ether to obtain the title compound (15 g). Analytical data presented in Table 1.
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