ms in the total ion chromatogram 1 h nmr 300 mhz cdcl 3 1 28 t j 6 9 hz 3h 1 86 1 96 m 2h 2 72 br 1h 3 09 3 48 m 7h 3 86 4 21 m 5h 6 75 dd j 1 2 7 8 hz 1h 6 82 t j 7 8 hz 1h 6 90 dd j 1 2 7 2 hz 1h 6br 10as ethyl 2 3 6b 9 10 10a hexahydro 3 methyl 1h pyrido 3 u2032 4 u2032 4 5 pyrrolo 1 2 3 de quinoxaline 8 carboxylate may be prepared by adding bh 3 thf 1m in thf 143 ml 143 mmol dropwise at room temperature over 15 minutes to a suspension of 6br 10as ethyl 2 3 6b 9 10 10a hexahydro 3 methyl 2 oxo 1h pyrido 3 u2032 4 u2032 4 5 pyrrolo 1 2 3 de quinoxaline 8 carboxylate 18 0 g ca 57 mmol in 50 ml of thf the resulting mixture is heated to a reflux for 3 hours the reaction mixture is cooled in an ice water bath and 150 ml of 6n hcl is added dropwise after thf is removed in vacuo 2n naoh is added until ph 9 followed by extraction with 500 ml of dcm the dcm layer is washed with brine and dried over na.