4-Chloro-3- cinnoline

Atkinson and Taylor summarized the evidence in support of the earlier assumption, arising from the evidence discussed above, that quatemization occurs on N-1 and also showed that 4-amino-, 4-amino-6-nitro-, and 4-amino-7-chloro-cinnoline gave two salts with methyl iodide, while 4-amino-8-nitrocinnoline gave only one salt and the... 

Even though data for a quantitative comparison are lacking, the effect of the position of benzo-fusion onto pyridazines is analogous to that with pyridines in producing the very poorly reactive 3-chloro-cinnoline (396) and highly reactive 1-chlorophthalazine (Table XV, lines 8 and 9). 

Vinogradova OV, Sorokoumov VN, Balova lA (2009) A short route to 3-alkynyl-4-bromo (chloro)cinnolines by Richter-type cyclization of OTtho-(dodeca-l,3-diynyl)aryltriaz-l-enes. Tetrahedron Lett 50 6358-6360... 

Cinnolin-4(lF/)-one and its 6-chloro, 6-bromo, 6-nitro and 8-nitro derivatives react with sulfuryl chloride or bromine in acetic acid to give the corresponding 3-halo derivatives in about 20% yields. lodination of 8-hydroxycinnolin-4(lF/)-one with a mixture of potassium iodide and potassium iodate gives the 5,7-diiodo derivative the 6,8-diiodo derivative is formed from 5-hydroxycinnolin-4(lF/)-one. 

Vasilevsky et al. reported that diazotization of phenylethynylaminopyrazole 19 in hydrochloric or hydrobromic acid furnished the 4-chloro- or 4-bromo cinnoline derivative... 

Aryloxy, hydroxy arylsulfonyloxy, and phosphoryloxy. The 4-toluenesulfonyloxy and 4-nitrophenyloxy groups approximate the chloro group in replaceability in benzene derivatives. The former appears to be less reactive than chloro toward hydroxide on quinoline and -phenoxy on pyrimidine is relatively unreactive toward sulfanilamide anion or ammonia. On cinnoline, quinazoline, or quinoline, a 4-phenoxy group is less reactive than a chloro group. 

The rate of amination and of alkoxylation increases 1.5-3-fold for a 10° rise in the temperature of reaction for naphthalenes (Table X, lines 1, 2, 7 and 8), quinolines, isoquinolines, l-halo-2-nitro-naphthalenes, and diazanaphthalenes. The relation of reactivity can vary or be reversed, depending on the temperature at which rates are mathematically or experimentally compared (cf. naphthalene discussion above and Section III,A, 1). For example, the rate ratio of piperidination of 4-chloroquinazoline to that of 1-chloroisoquino-line varies 100-fold over a relatively small temperature range 10 at 20°, and 10 at 100°. The ratio of rates of ethoxylation of 2-chloro-pyridine and 3-chloroisoquinoline is 9 at 140° and 180 at 20°. Comparison of 2-chloro-with 4-chloro-quinoline gives a ratio of 2.1 at 90° and 0.97 at 20° the ratio for 4-chloro-quinoline and -cinnoline is 3200 at 60° and 7300 at 20° and piperidination of 2-chloroquinoline vs. 1-chloroisoquinoline has a rate ratio of 1.0 at 110° and 1.7 at 20°. The change in the rate ratio with temperature will depend on the difference in the heats of activation of the two reactions (Section III,A,1). 

Diazine A -oxides can be regioselectively formed with H2O2 in formic acid as exemplified by the reaction of 2-chlorobenzo[/]cinnolines, 2-chloro-5,6-dihydrobenzo[/]cinnolines, and 3-chloro-9//-indeno[2,l-f]pyridazines <2000AP341>. This area was extensively discussed in CHEC(1984) <1984CHEC(2)1>. 

A Suzuki coupling of 5-chloro-2-methyl-6-phenyl-2H-pyridazin-3-one (10) ultimately led to diazino-fused indole 11 and cinnoline 12 and allowed access to a novel pyrimidoisoquinoline ring system in a one-pot fashion <02T10137>. Mn(II)-azido networks of the type [Mn(N3)2(L)] like 13 with new 3-D topologies were obtained using both pyridazine and pyrimidine ligands <02CC64>. 

Illuminati and co-workers have recently reported additional data on the effects of benzo-ring substituents on the rate of methoxy-dechlorination of quinolines, quinoxalines, and cinnolines the accelerations and decelerations reflect the decreases and increases in activation energy. Both 6- and 7-chloro groups increase the rate (by 6- and... 

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