[CH2:1]([NH2:5])[CH2:2][CH2:3][CH3:4].[N:6]1([C:15]2[O:20][C:19](=[O:21])[C:18]3[C:22]([CH2:26][CH3:27])=[CH:23][CH:24]=[CH:25][C:17]=3[N:16]=2)[C:10]2C=C[CH:13]=[CH:14][C:9]=2N=N1.C(OCC)(=O)C>C(Cl)Cl.C1(C)C=CC=CC=1>[CH2:1]([NH2:5])[CH2:2][CH2:3][CH3:4].[CH2:10]([NH:6][C:15]1[O:20][C:19](=[O:21])[C:18]2[C:22]([CH2:26][CH3:27])=[CH:23][CH:24]=[CH:25][C:17]=2[N:16]=1)[CH2:9][CH2:14][CH3:13]A standard solution of n-butylamine was prepared by adding 0.5 ml of n-butylamine to a 10 ml volumetric flask containing 10 ml dry methylene chloride. The n-butylamine solution (0.85 ml) was then added to 2-(1-benzotriazolyl)-5-ethyl-4H-3,1-benzoxazin-4-one (150 mg), prepared as described in Preparation VII above, in 21 mg of dry methylene chloride, and the mixture was stirred for 20 minutes. Analysis by TLC (20% ethyl acetate in toluene) indicated that the reaction was complete. The methylene chloride was then removed under reduced pressure and the remaining residue chromatographed over silica gel (10% ethyl acetate in toluene, flash column chromatography). All product fractions were combined and evaporated to give a solid that was recrystallized from pentane, yielding 40 mg of 2-n-butylamino-5-ethyl-4H-3,1-benzoxazin-4-one, m.p. 136°-137° C., IR, 330, 1725-1740 (broad), 1635, 1590, 1570 cm-1); 'H NMR(delta CDCl3): 1.0 (t, 3H, CH 3); 1.3 (t, 3H, CH3); 1.5 (m, 4H, CH2CH2); 3.2 (q, 2H, PhCH2); 3.4 (q, 2H, CH2NH); 4.8 (broad, s, 1H, NH); 6.9-7.6 (m, 3H, ArH).
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