Studies on the syntheses of N-heterocyclic compounds. xxviii. syntheses of pyrido[3,4-d]pyridazine derivatives. (4).
作者:KIYOSHI OMURA、NORIO TADA、MITSUMI TOMIMOTO、YOSHIRO USUI、YOSHIKAZU OKA、SHOJIRO YURUGI
DOI:10.1248/cpb.24.2699
日期:——
A variety of 7, 8-disubstituted 1, 4-dimorpholinopyrido [3, 4-d] pyridazine derivatives were synthesized in connection with the structure-activity relationships on diuretic activity. 1, 4-Dipolar cycloaddition of 4-alkyl- and 4-benzyl-5-ethoxyoxazoles with dimethyl maleate afforded dimethyl 6-alkyl- and 6-benzyl-5-hydroxy-pyridine-3, 4-dicarboxylate (3), which were alkylated to give the corresponding 5-alkoxypyridine derivatives (4). The cycloaddition of 5-alkyl- or 5-benzyl-4-phenyloxazole (9) with N-phenylmaleimide gave an adduct (10), heating of which under acidic condition effected dehydration to give 5-alkyl- or 5-benzyl-N, 6-diphenylpyridine-3, 4-dicarboximide (11). Reactions of 4 and 11 with hydrazine gave pyrido [3, 4-d] pyridazine-1, 4 (2H, 3H)-dione derivatives (5 and 12), chlorination of which followed by substitution with morpholine afforded 7-alkyl- and 7-benzyl-8-alkoxy-pyrido [3, 4-d] pyridazine derivatives (7a-k) and 8-alkyl- and 8-benzyl-7-phenyl derivatives (14a, 14b, and 14c). Also prepared were 8-methyl-7-substituted phenyl (14d and 15), 8-chloro- (19 and 21), 8-alkoxy-7-phenyl (26a, 26b, and 26c), and 7-methyl-8-phenyl (43) derivatives. Stereochemistry of the adduct (8) obtained by the 1, 4-cyclo-addition reaction of 4-phenyloxazole and N-phenylmaleimide was discussed.
结合利尿活性的结构-活性关系,合成了多种 7,8-二取代的 1,4-二吗啉并吡啶并 [3,4-d] 哒嗪衍生物。将 4-烷基和 4-苄基-5-乙氧基噁唑与马来酸二甲酯进行 1,4-二极环化反应,可得到 6-烷基和 6-苄基-5-羟基吡啶-3,4-二甲酸二甲酯(3),将其烷基化可得到相应的 5-烷氧基吡啶衍生物(4)。5- 烷基或 5-苄基-4-苯基恶唑(9)与 N-苯基马来酰亚胺发生环加成反应,得到加合物(10),在酸性条件下加热使其脱水,得到 5-烷基或 5-苄基-N,6-二苯基吡啶-3,4-二甲酰亚胺(11)。4 和 11 与肼反应,得到吡啶并[3,4-d]哒嗪-1,4 (2H,3H)-二酮衍生物(5 和 12),将其氯化,然后用吗啉取代,得到 7-烷基和 7-苄基-8-烷氧基吡啶并[3,4-d]哒嗪衍生物(7a-k)和 8-烷基和 8-苄基-7-苯基衍生物(14a、14b 和 14c)。此外,还制备了 8-甲基-7-取代苯基(14d 和 15)、8-氯(19 和 21)、8-烷氧基-7-苯基(26a、26b 和 26c)以及 7-甲基-8-苯基(43)衍生物。讨论了 4-苯基噁唑和 N-苯基马来酰亚胺通过 1,4-环加成反应得到的加合物(8)的立体化学。