[Formations and reactions of aromatic furazan compounds].
A reaction from various kinds of nitroquinoline with hydroxylamine in potassium hydroxide alkalinity produced a novel product, furazanoquinoline, besides the known amino derivatives. The products obtained were furazano [3,4-f] quinoline (5) from 5-nitroquinoline (1) and 6-nitroquinoline (6), and furazano [3,4-h] quinoline (10) from 7-nitroquinoline (8) and 8-nitroquinoline (11). The reaction mechanism was believed to be as shown in Figs. 2 and 3. The photoreaction of benzofuroxan (19) in acetonitrile containing a little water, under a high pressure mercury lamp, produced 1H-azepine-2,7-dione (20), while under irradiation using a low pressure lamp, 6H-furazano [4,5-c] carbazole-3-oxide (21) and compound 20 were obtained. Then the photoproduct 20 produced photodimer 22 by irradiation in acetonitrile: water (9:1, v/v) using a high or low pressure mercury lamp, while photolysis with alkali proceeded as in the photoreaction of N-alkylimide to give 7-hydroxy-1H-azepine-2-one (23). When pyrido [2,3-c] furoxan (24) was irradiated in acetonitrile containing a little water with a low pressure mercury lamp, 3-nitro-2-pyridone (25) was obtained. When compound 24 was irradiated in the presence of morpholine with a low pressure mercury lamp in an argon atmosphere, 6-morpholinopyridine 2,3-dioxime (26) was produced. Quinoxaline 1,4-dioxide derivatives (31, 33), phenazine 5,10-dioxide derivatives (36, 37) and pyrido [2,3-b] pyrazine derivatives (38, 39) were synthesized from the corresponding furoxan catalyzed by silica gel or molecular sieves, and their antibacterial properties were evaluated. The results of antibacterial screening tests in vitro, revealed strong activity against Bacteroides fragilis.
The reactions of benzofuroxan with carbonyl compounds on the surface of solid catalysts
The cyclocondensations of benzofuroxan (1a) with carbonyl compounds were smoothly and efficiently carried out by the adsorption of the components on the surface of silica gel or a molecular sieve to form a 2,3-disubstituted quinoxaline 1,4-dioxide. When the reactions using a molecular sieve 3A (powder) were carried out at 90 o , the actual reaction times were reduced to 0.5-2 hours. Although Duerckheimer has reported the isolation of only the 7-substituted quinoxaline 1,4-dioxide when 5-methoxybenzofuroxan (1e) was allowed to react with ethyl acetoacetate (2j), it produced only the 6-methoxy isomer as the reaction product by our method. 5-Carboxybenzofuroxan (1f) did not react with the carbonyl compound
Kleine Kohlenstoff-Ringe, VIII Valenzisomerisierung von cis- und trans-2-Vinyl-cyclopropylisocyanat†
cis- und trans-2-Vinyl-cyclopropylisocyanat wurden ausgehend von dem Addukt aus Butadien und Diazoessigester nach herkommlichen Methoden synthetisiert. Das cis-2-Vinyl-cyclopropylisocyanat konnte allerdings nicht in Substanz gefast werden, da es sich bereits unter seinen Bildungsbedingungen (70°) durch eine Valenzisomerisierung vom Typus der Cope-Umlagerung, gefolgt von einer Prototropie, in das zweifach ungesattigte Siebenring-Lactam III umwandelt. Die Isomerisierung des trans-2-Vinyl-cyclopropylisocyanats, die ebenfalls III liefert, erfordert demgegenuber eine Pyrolyse bei 350°. cis- und trans-2-Vinyl-cyclopropylisocyanat entsprechen somit in ihrem thermischen Verhalten vollig dem Isomerenpaar cis- und trans-1.2-Divinyl-cyclopropan. Es werden weiterhin Versuche zur Uberfuhrung des Lactams III in Azepine beschrieben.