dropwise to the mixture and the cooling bath was removed after stirring at about 23 u00b0 for about 15 hours the reaction was quenched by the careful addition of saturated nh 4 cl solution the mixture was poured into water and extracted into ether the ether extracts were dried brine mgso 4 and concentrated in vacuo purification of the crude material by flash chromatography 20 1 hexanes et 2 o yielded the dihydroquinoline as a yellow oil 1 3 g 2 97 mmole 75 ir film 3372 2964 1652 1598 1448 1258 1168 cm 1 1 h nmr cdcl 3 u03b4 1 26 s 6h 1 59 s 9h 1 65 m 2h 1 67 s 3h 1 95 s 3h 1 95 2 15 m 10h 2 16 m 2h 2 86 t j 7 2 hz 2h 3 72 br s 1h 5 08 m 3h 5 26 s 1h 6 40 d j 1 8 hz 1h 6 57 d of d j 8 0 1 8 hz 1h 6 94 d j 8 0 hz 1h ms m e 438 mh anal calcd for c 29 h 43 n 1 s 1 4 nitrobenzyl chloride 5.