the compound prepared in example 1 phthaloyl d cycloserine 9 28 g 40 mmole was dissolved in 100 ml of nitromethane phosphorous oxychloride 4 ml 43 mmole was added to the solution which was then heated up to 100 u00b0 c in a two hour period and kept at that temperature for an additional hour the mixture was cooled to room temperature and the solids were filtered off the filtrate was concentrated and the residue was extracted with ethyl acetate the solvent was removed and the product was purified by flash chromatography and eluted with 3 1 petroleum ether ethyl acetate to yield 3 chloro 4 phthalimido 4 5 dihydroisoxazole 5 49 g 3 chloro 4 phthalimido 4 5 dihydroisoxazole 1 0 g 4 mmole was dissolved in 25 ml of dried tetrahydrofuran and cooled to 0 u00b0 c diethylamine 25 ml was added to the solution which was then stirred at room temperature for 24 hours the product was concentrated and the residue purified by flash chromatography and eluted with 1 1 petroleum ether ethyl acetate the yield was 48 6 3 chloro 4 phthalimido 4 5 dihydroisoxazole 6 g 24 mmole was dissolved in 200 ml of dried tetrahydrofuran after which morpholine 20 9 g 240 mmole was added the reaction.