Studies on Heterocyclic Analogs of Azulene. VI. Cycloadditions of Styryl-substituted Aza Analogs of Azulene with Dimethyl Acetylenedicarboxylate
作者:Noritaka Abe、Tarozaemon Nishiwaki
DOI:10.1246/bcsj.53.1406
日期:1980.5
8-[(E)-Styryl]-1-azaazulenes stereospecifically react with dimethylacetylenedicarboxylate to form trans-7H-6a-azacyclobuta[j]cyclopent[cd]azulene (3), which undergoes thermal rearrangement into 3-[(E)-styryl]3H-2a-azacyclopent[cd]azulene and 3a,4-dihydro-3H-2a-azadicyclopent[cd, ij]azulene (7), or isomerization into 3H-2a-azacyclopenta[ef]heptalene by silica gel. Compound 7 is oxidized during the
Reactions of diethyl azulene-1,3-dicarboxylate derivatives and 1-azaazulene derivatives with Grignard reagents, and alkyl- and aryllithium
作者:Tadayoshi Morita、Noritaka Abe、Kahei Takase
DOI:10.1039/b003078n
日期:——
Reactions of diethyl azulene-1,3-dicarboxylate (1) and diethyl 2-chloroazulene-1,3-dicarboxylate (11) with Grignard reagents, followed by dehydration with tetrachloro-1,2-benzoquinone, gave 2-, 4,- and 6-substituted addition–oxidation products. Grignards reagents have a tendency to react with 1 at the positions in the order of 2 > 4 > 6, while steric hindrance has a greater influence at the positions in order of 2 > 4 > 6. Reactions of 1 and 11 with phenyllithium and methyllithium gave similar results. On the other hand, on the reaction of diethyl 2-methoxyazulene-1,3-dicarboxylate (15), Grignard reagents attacked preferentially at the methoxy group, and 2-substituted products were obtained. Use of excess molar equivalents of Grignard reagents led to diaryl-substituted products. Reaction of 2-chloro-1-azaazulenes with Grignard reagents also gave similar addition–oxidation products, and reacted at the positions in the order 8 ≫ 4 > 6, whereas reaction of 2-methoxy-1-azaazulene with a Grignard reagent gave 1-azaazulen-2(1H)-one.
The title azaazulene 3 was synthesized either by reaction of tropone with N-(2-pyridyl)acetyl}pyridinium iodide in the presence of ammonium acetate or by palladium-catalyzed cross-coupling between 2-halo-1-azaazulene and 2-substituted pyridine. The compound shows relatively stronger basicity compared with 2,2′-bipyridyl. While 3 showed no emission from the S1 state but from the S2 state like azulene
Synthesis of 1,2,5a-Triazacyclohept[<i>a</i>]azulen-5(2<i>H</i>)-ones
作者:Noritaka Abe、Yoshifumi Emoto
DOI:10.1246/bcsj.61.1440
日期:1988.4
Reactions of 2-hydrazino-1-azaazulenes with acetylacetone gave 2-(3,5-dimethyl-1-pyrazolyl)-1-azaazulenes. Cyclizations of diethyl (1-azaazulen-2-yl)hydrazinomethylenemalonates in refluxing t-butylbenzene or on silica gel gave 1,2,5a-triazacyclohept[a]azulen-5(2H)-ones.
We herein report the synthesis of 2-(2-methoxyphenyl)-1-azaazulene (8) by a Suzuki–Miyaura cross-coupling reaction between 2-chloro-1-azaazulene and 2-methoxyphenylboronic acid and also by the condensation of tropone and the ylide derived from 1-(o-methoxyphenacyl)pyridinium iodide. Demethylation of 8 afforded the title compound 6. X-ray crystallographic analysis of 6 provided evidence for an intramolecular