The 1,4-oxazin-3-one from Step B was dissolved in 50 ml of tetrahydrofuran and added dropwise to 0.3 g (0.008 m) of lithium aluminum hydride in 50 ml of tetrahydrofuran. The mixture was heated at reflux temperature for one hour, cooled and treated with sufficient saturated aqueous sodium sulfate solution to quench excess lithium aluminum hydride. The mixture was filtered and concentrated to dryness in vacuo. The residue was dissolved in methylene chloride, dried (Na2SO4), and concentrated to dryness in vacuo to a residue of crude product (2.1 g, 81%). The maleate salt was prepared by treating with a stoichiometric amount of maleic acid in a minimum of warm isopropanol and adding ether to the cooled solution to incipient cloudiness. After precipitation was complete the salt was collected and recrystallized from benzene to give trans-4-ethyl-2,3,4,4a,5,6,7,11b-octahydrobenzo[6,7]cyclohept[1,2-b]-1,4-oxazine hydrogen maleate, m.p. 132°-135° C.
