Studies on Quinazolines. VII. Reactions of Anthranilamide with .BETA.-Diketones; New Approaches toward the Synthesis of Tetrahydropyrido(2,1-b)quinazolin-11-one Derivatives.
作者:Ji-Wang CHERN、Hui-Ting CHEN、Nan-Yi LAI、Kuo-Rong WU、Yu-Chin CHERN
DOI:10.1248/cpb.46.928
日期:——
Condensation of anthranilamide and its derivatives with various 1, 3-cyclohexanediones 5a, b or 2, 4-pentanediones under acidic conditions produced a variety of heterocycles, leading to the synthesis of tetrahydropyrido[2, 1-b]-quinazolin-11-one derivatives. Condensation of anthranilamide with 5a or 5b in the presence of p-toluenesulfonic acid at the reflux temperature of tetrahydrofuran (THF) afforded compound 6a (40%) and compound 7a (22%) or compound 6b (47%) and compound 7b (39%), respectively. However, reflux of anthranilamide with 5a or 5b in 6% ethanolic hydrogen chloride provided compounds 6a and 6b in 77% and 73% yields, respectively. Heating 7a with 5a in 6% ethanolic hydrogen chloride furnished 6a in 82.4% yield. Reaction of anthranilamide with 5c under the same conditions resulted in the formation of 11 (57%). Treatment of compounds 6a and 6b with NaBH4 furnished 8a, b (89, 87% yields), which were subsequently subjected to the Mitsunobu reaction to produce 6, 7, 8, 9-tetrahydro-9-methyl-11H-pyrido[2, 1-b]quinazolin-11-one (9a) and 6, 7, 8, 9-tetrahydro-7, 7, 9-trimethyl-11H-pyrido[2, 1-b]quinazolin-11-one (9b) in 56 and 72% yields, respectively. However, heating 14 with 15a in CH3CN in the presence of p-toluenesulfonic acid furnished 19 in 31% yield. Under similar conditions, treatment of 21 with 15a provided 23a (42.4% yield), a key intermediate for the synthesis of rutaecarpine. Analogous reaction of 21 with 15b, 15c and 5a provided 22b-d in 63-99.3% yield, respectively.
在酸性条件下,蒽酰胺及其衍生物与各种1,3-环己二酮(5a, b)或2,4-戊二酮的缩合反应生成了多种杂环化合物,从而合成了四氢吡啶[2,1-b]喹唑啉-11-酮衍生物。在四氢呋喃(THF)回流温度下,蒽酰胺与5a或5b在对甲苯磺酸的存在下缩合,分别得到化合物6a(40%)和化合物7a(22%)或化合物6b(47%)和化合物7b(39%)。然而,在6%乙醇盐酸中回流蒽酰胺与5a或5b,分别得到了化合物6a和6b,产率为77%和73%。将7a与5a在6%乙醇盐酸中加热处理,得到了6a,产率为82.4%。在相同条件下,蒽酰胺与5c反应形成了11(57%)。对化合物6a和6b使用NaBH4处理,获得了8a、b(产率分别为89%和87%),随后进行了Mitsunobu反应,生成了6,7,8,9-四氢-9-甲基-11H-吡啶[2,1-b]喹唑啉-11-酮(9a)和6,7,8,9-四氢-7,7,9-三甲基-11H-吡啶[2,1-b]喹唑啉-11-酮(9b),产率分别为56%和72%。然而,在对甲苯磺酸存在下,在CH3CN中加热14与15a,得到了19,产率为31%。在类似条件下,将21与15a处理得到了23a(产率42.4%),这是合成鲁塔卡平的一个关键中间体。与21反应的15b、15c和5a的类似反应,分别得到了产率为63%-99.3%的22b-d。