Reactions of various substituted quinoline 1-oxides with cyanogen bromide in ethanol were investigated. The corresponding ethyl N-(8-quinolyl) carbamates were formed in most cases, but their yields were rather low except reactions of N-oxides of 4-quinolinol (If), 4-aminoquinoline (Ig), 2-quinolinol (IXf), 5-nitroquinoline (XXVI) and 6-chloroquinoline (XXX). In addition to 8-quinolylcarbamates, 2-quinolylcarbamates (VIc and VIe) were obtained from reactions of 4-ethoxyquinoline 1-oxide (Ic) and lepidine 1-oxide (Ie), and further the 6-quinolylcarbamate (VII) was also isolated in the latter case. The reaction of 4-quinolinol 1-oxide (If) gave the 3-quinolylcarbamate (VIII) as the main product besides 8-quinolyl derivatives, IIf and IIi. 2-Imino-1, 2, 4-oxadiazolo [2, 3-α] quinoline hydrobromide (XVI) was produced without the participation of ethanol in a good yield of 65% from the reaction of 2-aminoquinoline 1-oxide (IXg). From 8-ethoxycarbonylaminoquinoline 1-oxide (XX), a small amount of 2, 8-bis (ethoxycarbonylamino)-quinoline (XXI) was obtained. The features and mechanisms of some reactions were also discussed.
在
乙醇中对各种取代的
喹啉1-氧化物与
溴氰的反应进行了研究。在大多数情况下,生成了相应的乙基N-(8-
喹啉基)
氨基甲酸酯,但其产率相对较低,除了4-
喹啉醇(If)、
4-氨基喹啉(Ig)、
2-喹啉醇(IXf)、
5-硝基喹啉(XXVI)和
6-氯喹啉(XXX)的反应。除了8-
喹啉基
氨基甲酸酯外,
4-乙氧基喹啉1-氧化物(Ic)和雷必定1-氧化物(Ie)的反应还获得了
2-喹啉基氨基甲酸酯(VIc和VIe),另外在后者的反应中还分离得到了6-
喹啉基
氨基甲酸酯(VII)。4-
喹啉醇1-氧化物(If)的反应除了生成8-
喹啉基衍
生物IIf和IIi外,还主要生成了3-
喹啉基
氨基甲酸酯(VIII)。在没有
乙醇参与的情况下,从
2-氨基喹啉1-氧化物(IXg)的反应中以65%的良好产率生成了2-亚
氨基-1, 2, 4-噁二唑[2, 3-α]
喹啉溴化物(XVI)。从8-乙氧基羧
氨基
喹啉1-氧化物(XX)得到了一小部分2, 8-双(乙氧基羧
氨基)-
喹啉(XXI)。此外,还讨论了一些反应的特征和机理。