A new synthetic route to 1, 4-dimorpholino-7-phenylpyrido [3, 4-d] pyridazine (1), a potent diuretic, has been investigated. Chlorination and the subsequent dechlorination by catalytic hydrogenation of ethyl 3-cyano-2-oxo-6-phenyl-4 (1H)-pyridinecarboxylate (2) gave ethyl 3-cyano-6-phenyl-4-pyridinecarboxylate (6), which was also obtained by desulfurization of ethyl 3-cyano-6-phenyl-2-thioxo-4 (1H)-pyridinecarboxylate (3). 6 was led to 7-phenylpyrido [3, 4-d] pyridazine-1, 4 (2H, 3H)-dione (12), a key intermediate in the synthesis of 1, by way of cyclic imide (10) or anhydride (11). Several homologs of 1 could also be prepared by employing these procedures. Reactivity of the three chloro groups in 1, 4, 5-trichloro-7-phenylpyrido [3, 4-d] pyridazine (18) towards nucleophilic substitution with morpholine is discussed.
一种新的合成路线用于1,4-二吗啉基-7-苯基
吡啶并[3,4-d]哒嗪(1)的合成,这是一种有效的利尿剂。通过催化氢化3-
氰基-2-氧代-6-苯基-4(1H)-
吡啶甲酸乙酯(2)进行
氯化反应和后续脱
氯反应,得到3-
氰基-6-苯基-4-
吡啶甲酸乙酯(6),该物质也可以通过3-
氰基-6-苯基-2-
硫代-4(1H)-
吡啶甲酸乙酯(3)的脱
硫反应得到。6通过环状
亚胺(10)或酸酐(11)转化为7-苯基
吡啶并[3,4-d]哒嗪-1,4(2H,3H)-二酮(12),后者是合成1的关键中间体。1的几种同系物也可以通过这些方法制备。1,4,5-三
氯-7-苯基
吡啶并[3,4-d]哒嗪(18)中的三个
氯基团与吗啉发生亲核