To a solution of 5-isothiocyanato-1,3-dihydro-indol-2-one (2.3 g, 12.09 mmol) in dry dichloromethane (200 ml), 1,2-diamino-pyrazinium mesitylenate (5.21 g, 15.12 mmol), diisopropylethylamine (7.81 g, 60.45 mmol) and EDCI (4.63 g, 24.18 mmol) are added and stirred for 6 hours. The reaction mixture is concentrated and the residue is taken in water (100 ml), triturated and filtered, the crude solid is purified by silica column using (60-120) mesh to get the titled product as yellow solid (2.0 g, 55%);
