Methyl (Z)-2-[(benzyloxycarbonyl)amino]-3-dimethylaminopropenoate (1) was used as a reagent for preparation of 3-[(benzyloxycarbonyl)amino] substituted 4H-pyrido[1,2-a]pyrimidin-4-ones 17-21, 4H-pyrimido[1,2-b]pyridazin-4-ones 22 and 23, 5H-[1,2,4]triazolo[2,3-a]- pyrimidin-5-one 24, 5H-thiazolo[3,2-a]pyrimidin-5-one 25, and 4H-pyrazino[1,2-a]pyrimidin-4-one 26. Removal of the benzyloxycarbonyl group by catalytical transfer hydrogenation with Pd/C in the presence of cyclohexene is selective to give 3-amino-4H-pyrido[1,2-a]- pyrimidin-4-ones 27-30 in 85-92% yields, or with hydrogen bromide in acetic acid to give 3-amino-4H-pyrimido[1,2-b]pyridazin-4-one (31) and 6-amino-5H-thiazolo[3,2-a]pyrimidin-5-one (32) in 80% yields.
甲基(Z)-2-[(苄氧羰基)氨基]-3-二甲基氨基丙烯酸酯(1)被用作3-[(苄氧羰基)氨基]取代的4H-吡啶并[1,2-a]嘧啶-4-酮17-21,4H-嘧啶并[1,2-b]吡啉并[1,2-b]吡啉-4-酮22和23,5H-[1,2,4]三唑并[2,3-a]嘧啶-5-酮24,5H-噻唑并[3,2-a]嘧啶-5-酮25和4H-吡嗪并[1,2-a]嘧啶-4-酮26的制备试剂。在Pd/C存在下和环己烯的存在下,通过催化转移氢化去除苄氧羰基团是选择性的,可以得到85-92%产率的3-氨基-4H-吡啶并[1,2-a]嘧啶-4-酮27-30,或者通过在乙酸中使用溴化氢得到3-氨基-4H-嘧啶并[1,2-b]吡啉并[1,2-b]吡啉-4-酮(31)和6-氨基-5H-噻唑并[3,2-a]嘧啶-5-酮(32)80%的产率。