diethyl 1-(1-cyanoethyl)-1H-indole-2,6-dicarboxylate → Ethyl 4-methyl-1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-7-carboxylate
Reaction equation
[C:1]([CH:3]([N:5]1[C:13]2[C:8](=[CH:9][CH:10]=[C:11]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[CH:12]=2)[CH:7]=[C:6]1[C:19]([O:21]CC)=O)[CH3:4])#[N:2]>C(O)C.[Pt]=O>[CH3:4][CH:3]1[N:5]2[C:13]3[CH:12]=[C:11]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[CH:10]=[CH:9][C:8]=3[CH:7]=[C:6]2[C:19](=[O:21])[NH:2][CH2:1]1Participants
4
Procedure
To a solution of diethyl 1-(1-cyanoethyl)-1H-indole-2,6-dicarboxylate (3.9 g, 12.4 mmol) in ethanol (500 mL) is added platinum oxide (2.0 g, 8.8 mmol). The reaction mixture is then shaken under 50 psi of H2 for 4 h. Additional platinum oxide (700 mg, 3.1 mmol) is added along with more ethanol (10 mL) and the mixture is shaken under 50 psi of H2 for another 16 h. The reaction mixture is filtered through Celite under a flow of N2 and the Celite is rinsed with EtOAc. The filtrates are combined and concentrated to afford the title compound (3.2 g, 95%) which is used in the next step without further purification.