solution of residue in supersaturated methanol ammonia 250 ml was stirred at 25 u02dc 30 u00b0 c for over 24 hours and white solid was precipitated crystal grew in an ice bath for 2 hours after filter the cake was dried under reduced pressure to give 44 4 g of white crystal yield 67 mp 190 u02dc 192 u00b0 c 1 h nmr 300 mhz dmso d 6 u03b4 4 29 d 1h 4 56 d 1h 7 56 s 1h 6 59 d 1h 7 34 t 1h 6 88 d 1h 4 70 m 1h 2 01 m 2h 2 20 m 1h 2 02 m 1h 6 59 s 1h 6 74 s 1h 4 38 s 2h 7 14 u02dc 7 40 m 7h 1 h nmr 300 mhz dmso d 6 d 2 o u03b4 4 29 d 1h 4 56 d 1h 6 59 d 1h 7 34 t 1h 6 88 d 1h 4 70 m 1h 2 01 m 2h 2 20 m 1h 2 02 m 1h 4 38 s 2h 7 14 u02dc 7 40 m 5h phenomenex luna 5 u c18 250 mm u00d7 4 6 mm velocity 1 0 ml min u03bb 230 nm 3 4.