ethyl n tert butoxycarbonyl glycine 576 mg 1 2 mmol as per the procedure of example 9 1 h nmr 500 mhz dmso d 6 u03b4 8 28 d 1h 7 68 d 1h 4 16 dd 2h 3 99 s 3h 3 96 s 2h 3 56 dd 2h the title compound was synthesized from n 2 benzothiazole 2 sulfonylamino ethyl n tert butoxycarbonyl alanine as per the procedure of example 9 1 h nmr 500 mhz dmso d 6 u03b4 9 80 brs 2h 8 35 m 1h 8 25 m 1h 7 75 u02dc 7 70 m 2h 4 31 u02dc 4 25 m 2h 4 17 m 1h 3 70 m 1h 3 55 m 1h 1 34 d 3h the reaction mixture of cytosin 1 yl acetic acid 3 94 g 20 mmol and 1 1 u2032 carbonyldiimidazole 4 86 g 30 mmol in dmf was stirred for 25 min at 100 u00b0 c then piperonyl alcohol 6 08 g 40 mmol was added to the reaction mixture the resulting reaction mixture was allowed to cool to room temperature for 2 h the solvent was removed in vacuo and the residue was dissolved in ethyl acetate 100 ml the solution was washed with water 100 ml u00d7 2 dried over mgso 4 and filtered the filtrate was concentrated in vacuo and treated with ethyl ether to afford white solid the solid was filtered off and dried in vacuo to give the desired product 7 20 g 96 1 h nmr 500 mhz dmso d 6 u03b4 10 77 s 1h 8 04 d 1h 7 04 d 1h 7 00 s 1h 6.