3,4-DIHYDRO-2H-PYRIDO[1,2-A]PYRIMIDIN-2-ONE

Dissolve it in CHCl3, filter, evaporate, then recrystallise the residue from EtOH/Me2CO (needles) which can be washed with Et2O and dried. It can also be recrystallised from CHCl3/pet ether or CHCl3/hexane. The hydrochloride has m 295-295o (dec, from EtOH or MeOH/Et2O), the hydrobromide has m 299-300o(dec) (from MeOH/Et2O) and the picrate has m 224-226o(corr), m 219-220o from EtOH. [Adams & Pachter J Am Chem Soc 74 4906 1952, Lappin J Org Chem 23 1358 1958, Hurd & Hayao J Am Chem Soc 77 115 1955, Beilstein 24 III/IV 299.]