Quinolines 6-alkoxy

Quinazoline methiodide, 29 Quinazoline 3-oxides, 31 Quinazoline-thiones, 31, 51 4-Quinazolone, 3-alkyl-, 31 Quindolines, 103, 134, 144, 146 Quindoline-11-carboxylic acid, 144 Quinindoline, 135, 144 Quinolines, alkoxy-, reactions of, 311 2-alkyl-, reaction with carbenes, 77 aza-effects in, 318 basicity of, 244, 245, 247, 288, 289... 

Friedlander synthesis, 2, 445 Quinoline, alkenyl-1,2-dihydro-disproportionation, 2, 369 Quinoline, 2-alkoxy-reactions, 2, 351 Quinoline, 4-alkoxy-reactions, 2, 351 Quinoline, 2-alkoxy-4-hydroxy-synthesis... 

An acid-catalyzed substitution of a 6-oxo group on 2-aminopteridine-4,6-dione with hydrogen chloride in alcohols (65-100°, 3 hr, 80% yield) represents a convenient synthesis of the 6-alkoxy analogs. The reaction proceeds also with pteridine-2,4,6-trione and its 1-methyl and 1,3-dimethyl derivatives. While methoxylation of 2,4,7-trichloro-quinoline gives about equal amounts of 2- and 4-substitution, acid-catalyzed hydrolysis gives specific reaction at the 2-position only. ... 

Indirect deactivation by an alkoxy group is apparent in the sluggish reaction of 4-butoxy-2-chloroquinoline with w-butylamine (EtOH, 5 hr, 180°, but not at 80°). The chloro group in 2-chloro-4-ethoxy-quinoline is more reactive than that in the 4-chloro-2-ethoxy isomer toward alkoxides or amines in spite of the usually more effective para indirect deactivation in the former. For kinetic data on quinolines see Tables X and XI, pp. 336 and 338, respectively. 

Reaction of 2,4,7-trichloroquinoline with sodium methoxide (65°, 30 min) yielded an equal mixture of 2,7-dichloro-4-methoxy- (40%) and 4,7-dichloro-2-methoxy-derivatives (31%). The activating effect of the chloro groups is evident from the inertness of 4-chloro-quinoUne to methoxide ion at 65°. Alteration of the relative reactivity by cationization of the azine ring is again noted here in the acid-catalyzed hydrolysis (dilute HCl, 100°, 1.5 hr) of the trichloro compound to give 72% of the 2-hydroxylation product.Similarly, acid-hydrolysis of the alkoxy group proceeds much more readily in 2-ethoxy-4-chloro- than in 4-ethoxy-2-chloro-quinoline. ... 

Several 7-substituted (H, halogen, alkoxy, alkylthio, halogen, alkyl, carboxyl) oxazolo[5,4-/i]quinolines were found to be very effective against broadleaf weeds (90EUP1, 90GEP1). 

Since various substituents are tolerated, the Friedlander reaction is of preparative value for the synthesis of a large variety of quinoline derivatives. The benzene ring may bear for example alkyl, alkoxy, nitro or halogen substituents. Substituents R, R and R" also are variable. The reaction can be carried out with various carbonyl compounds, that contain an enolizable a-methylene group. The reactivity of that group is an important factor for a successful reaction. 

Acidic conditions are more favorable than thermal ring-closure for the formation of 5-substituted isomers. The isomeric ratio of 5- and 7-substi-tuted quinolines is less sensitive to conditions of ring closure in the case of A/r-(3-alkoxy- or 3,4-dialkoxy- or 3,4-alkylenedioxophenyl)aminomethy-lenemalonates (see Table V and following discussion). 

The 6-benzofuranylaminomethylenemalonate (928) can be regarded as both a /we/o-alkoxy-substituted and an aromatic ring condensed phenyla-mine derivative. On thermal ring closure in boiling Dowtherm A for 30 min, a 1 1 mixture of furo[3,2-g]quinoline-6-carboxylate (929) and furo [2,3-/]quinoline-8-carboxylate (930) was obtained in 70-80% yield (70GEP2021100 71BRP1240446), indicating that both the alkoxy substituted and the aromatic moiety exerted an influence. 

The Reissert-Henze and the Feely-Beavers-Tani reactions are considered together in this section because of their similarity. The former involves cyanation of acyloxy (formed in situ) (Scheme 113), and the latter alkoxy (Scheme 114), quaternary salts. The Reissert-Henze reaction is a facile, fairly general reaction for quinoline and isoquinoline AT-oxides (Table 19) with cyanation occurring a to the ring nitrogen. Certain substituents inhibit reaction, for example a 1-methyl group (equation 125), and others undergo replacement (Scheme 130) (81H(15)98l). Reaction of 1-methylisoquinoline 2-oxide with benzoyl chloride... 

There are a few routes to quinolines which can be viewed as modified Doebner-von Miller syntheses. When 4-alkoxydiphenylamines are treated with enol ethers or esters it is reported that 7V-(4-alkoxyphenyl)-2-methylquinolinium salts (599) are obtained (79ZOR1299) the alkoxy group must have an adverse effect on the cyclization. Arylamines... 

The principal type of ether cleavage classically employed in bisbenzyliso-quinoline alkaloid research is reductive reaction with Na/NH3, which cleaves diphenyl ether linkages, providing characterizable fragments. Numerous examples are to be found in Section II,C. A drawback is that methylenedioxy (e.g., see Section II,C, 131) and certain alkoxy (e.g., see Section II,C, 130) functions are also attacked, leading occasionally to ambiguous results quaternary alkaloids also suffer Hofmanmelimination (e.g., see Section II,C,131). 

Another chromophore, 8-alkoxy-5-chloroquinoline, was appended to the narrower rim of a calix[4]arene triamide, 44a and 44b (see fig. 38). If Nd111, Er111, and Ybm nitrates are added to acetonitrile solutions of these receptors, quenching of the methoxy quinoline luminescence oc-... 

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