[NH2:1][C:2]1[S:3][C:4]2[C:10](=[O:11])[CH2:9][C:8]([CH3:13])([CH3:12])[CH2:7][C:5]=2[N:6]=1.C1N=[CH:17][N:16]([C:19](N2C=NC=C2)=[O:20])[CH:15]=1.C1CCN2C(=NCCC2)CC1.CNC>C(#N)C>[CH3:12][C:8]1([CH3:13])[CH2:7][C:5]2[N:6]=[C:2]([NH:1][C:19](=[O:20])[N:16]([CH3:17])[CH3:15])[S:3][C:4]=2[C:10](=[O:11])[CH2:9]1
To a solution of 2-amino-5,5-dimethyl-5,6-dihydro-4H-benzothiazol-7-one (151 g, 0.768 mol) in acetonitrile (5 L) are added CDI (249 g, 1.53 mol) and DBU (233 g, 1.53 mol). The reaction mixture is stirred overnight at 100° C. Dimethylamine (310 g, 3.83 mol) is added at RT and the stirring is continued overnight at 100° C. After cooling to RT, the reaction mixture is concentrated in vacuo and the residue is poured into ice water. The pH of the mixture is adjusted to pH 5 with HCl (6 M). The aqueous mixture is extracted with ethyl acetate (4×500 mL). The combined organic layers are washed with brine (500 mL) and dried over anhydrous Na2SO4. The solvent is evaporated in vacuo to give crude product. The crude product is washed with water to give 3-(5,5-dimethyl-7-oxo-4,5,6,7-tetrahydro-benzothiazol-2-yl)-1,1-dimethyl-urea (169 g, 82% yield).
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