Yield:-

Reaction Conditions:

with Si-dimethylamine in N,N-dimethyl-formamide; for 1 h;

Steps:

6

3-t-Butoxycarbonylamino-benzyl-ammonium chloride (103.5 mg, 0.4 mmol) was dissolved in 1 rnL DMF in a reaction vial, and Si-dimethylamine (350 mg, 0.525 mmol) was added. The resulting mixture was agitated for 1 h, after which time/?- cyanophenylisocyanate (52 mg, 0.36 mmol) was added and the reaction mixture was agitated 8 h. SCX (113 mg, 0.1 mmol) was added and the mixture was agitated an additional 30 minutes. The reaction mixture was filtered, the flrate was concentrated, and the residue was dissolved in 5 mL dichloromethane. TFA (1 mL) was added and the mixture was stirred at room temperature for 1.5 hours. The solvents were evaporated providing 96 mg of pure intermediate (l-(3-amino-benzyl)-3-(4-cyano-phenyl)-urea) which was used directly. Synthesis of the second reagent was carried out by treating l,2,3,4-tetrahydro-isoquinoline-7-carboxylic acid methyl ester (139 mg, 0.727 mmol) with formaldehyde (1 mL, 37% aqueous) in formic acid (1 mL) and heating the resulting mixture for 62 h at 60 ⁰C. The reaction mixture was evaporated to dryness, and the residue was taken up in dichloromethane and evaporated (3x). The intermediate, 2 -methyl- 1,2, 3, 4- tetrahydro-isoquinoline-7-carboxylic acid methyl ester, was then dissolved in methanol (2 mL) and treated with Amberlyst A26 (OH^" form) (polymer-supported hydroxide exchange resin; 2240 mg, 3 mmol), and the resulting mixture was agitated overnight, then heated in the microwave at 130 ⁰C for 40 min. After cooling to room temperature, the resin was then filtered and washed with 1 x 2 mL DMF and 3 x 2 mL methanol. The product acid was eluted with a solution of 20% formic acid in methanol (3x2 mL). The eluant solvents were evaporated to provide the pure acid (2 -methyl- 1,2,3, 4-tetrahydro- isoquinoline-7-carboxylic acid) as a formate salt (110 mg, 66% - 2 steps). Coupling of the two reagents prepared above proceeded by dissolution of the acid (86 mg, 0.45 mmol), EDC (143.8 mg, 0.75 mmol), and HOBt (74 mg, 0.55 mmol) in DMF (1 mL). Subsequently N-methylmorpholine (0.1 mL, 0.9 mmol) was added and the resulting reaction mixture was agitated for 30 min. The urea (l-(3-amino-benzyl)-3-(4-cyano- phenyl)-urea) (110 mg, 0.413 mmol) was added and the resulting mixture was agitated for 48 h. The reaction mixture was purified directly by preparative HPLC using an acetonitrile/water/formic acid gradient providing the title compound as a formate salt (53 mg, 27% yield), MS analysis electrospray, 440 (M+H).

References:

WO2008/86047,2008,A1 Location in patent:Page/Page column 83-84