Quinoline iodides

B) Methiodi s. Members of Classes (i), (ii) and (iv) combine wdth methyl iodide (some very vigorously) to form quaternary methiodides. It is best to add the amine to an excess of methyl iodide dissolved in about twice its volume of methanol, allow any spontaneous reaction to subside, and then boil under reflux for 30 minutes (extend to 1 hour for Class (iv) except pyridine and quinoline). The methiodide may crystallise when the reaction-mixture cools if not, evaporate the latter to small bulk or to dryness, and recrystallise, (M.ps., pp. 553-554 )... 

An alternative method of removing the aniline is to add 30 ml. of concentrated sulphuric acid carefully to the steam distillate, cool the solution to 0-5°, and add a concentrated solution of sodium nitrite until a drop of the reaction mixture colours potassium iodide - starch paper a deep blue instantly. As the diazotisation approaches completion, the reaction becomes slow it will therefore be necessary to teat for excess of nitrous acid after an interval of 5 minutes, stirring all the whUe. About 12 g. of sodium nitrite are usually required. The diazotised solution is then heated on a boiling water bath for an hour (or until active evolution of nitrogen ceases), treated with a solution of 60 g. of sodium hydroxide in 200 ml. of water, the mixture steam-distilled, and the quinoline isolated from the distillate by extrsM-tion with ether as above. 

Excellent yields of the former product are also obtained with quinoline N-oxide. Improved yields of Reissert compounds are found under phase-transfer conditions (29). The regiochemistry of the method changes dramatically with /V-alkyl quin olinium salts, eg, /V-methy1quino1inium iodide [3947-76-0] (12), which form 4-cyanoquinoline [23395-72-4] (13) (30), through the intermediary in this example of A[-methyl-4-cyano-l,4-dihydroquinoline... 

Ewins has synthesised both substances from m-methoxybenzoic acid, which on nitration gave 2-nitro-3-methoxybenzoic acid, and this, on reduction and treatment with methyl iodide, yielded damasceninic acid, which, by esterification with methyl alcohol, furnished damascenine. Kaufmann and Rothlen found that the additive product of 8-methoxy-quinoline and methyl sulphate, on oxidation with permanganate, yields formyldamasceninic acid, MeO. CgH3(NMe. CHO). COOH, which can be transformed into damasceninic acid by warming with dilute hydrochloric acid. ... 

Primary halides are more reactive than secondary compounds quaternary salt formation does not occur with tertiary halides, elimination always occurring to give the hydriodide and an olefln, Also, the larger the alkyl group the slower is the reaction this is shown by the very slow reaction of dodecyl bromide with quinoline, and even butyl iodide is much slower to react than methyl iodide. The longer chain primary halides commonly undergo elimination rather than cause quaternization for example, n-octyl and cetyl iodides give only the hydriodides when heated with 9-aminoacridine. ... 

Methyl-thiazolo[4,5-/]quinoline 19 was methylated by methyl iodide on the nitrogen atom of pyridine giving the appropriate methodide. A subsequent oxidation with potassium hexacyanoferrate in alkaline media gave the 2,6-dimethyl-7-0x0-6,7-dihydrothiazolo[4,5-/]quinoline 21 (37LA60). 

The 2-methyl-4,9-dioxo-4,9-dihydrothiazolo[4,5-.g]quinoline was first quar-temized with methyl iodide on pyridine nitrogen and then treated with IV-methyl-quinolinium-4-yl salt, affording monomethine cyanine dyes 41 to study solva-tochromism, acid-base properties, and antimicrobial activities (95MI1). 

The nitration of l,2,5-selenadiazolo[3,4-/] quinoline 77 with benzoyl nitrate affords the 8-nitro derivative 78, whereas methylation with methyl iodide or methyl sulfate afforded the corresponding 6-pyridinium methiodide 79 or methosulfate 80, respectively (Scheme 29). The pyridinium salt 80 was submitted to oxidation with potassium hexacyanoferrate and provided 7-oxo-6,7-dihydro derivative 81 or, by reaction of pyridinium salt 79 with phenylmagnesium bromide, the 7-phenyl-6,7-dihydro derivative 82. Nucleophilic substitution of the methiodide 79 with potassium cyanide resulted in the formation of 9-cyano-6,9-dihydroderivative 83, which can be oxidized by iodine to 9-cyano-l,2,5-selenadiazolo [3,4-/]quinoline methiodide 84. All the reactions proceeded in moderate yields (81IJC648). 

When 2-amino-4-methylimidazo[4,5-/]quinoline (R = Me, R = H) was alkylated with methyl iodide in K2CO3-DMSO, a mixture of both 1//-1,4-dimethyl- and 3//-3,4-dimethyl derivatives was obtained (80CL1391). In the case of DMF-DMA or its bis-trideuterio analogue, methylation in the ratio 8 1 in favor of the 3//-isomer is preferred (88SC973). 

The yellow colored, sparcely soluble 5-ethyl-2-methyl-l l/f-pyrido[3,4-u] carbazolium 347 isolated from Aspidosperma gilbertii exists as a hydroxide after filtration of the corresponding iodide over basic aluminum oxide. A short synthesis was described (80CB3245). The Pyrido[3,4-a]carbazole ring system is present in the alkaloid AG-1, whereas Cryptolepine (348) possesses the indolo[3,2-b]quinoline moiety (65MI1). 

Treatment of 4-arylamino-8-iodoquinoline 268 with propargyl alcohol in presence of iodo(phenyl)bis(triphenylphosphine) palladium and copper (I)iodide afforded 269 which upon catalytic reduction using Linder s catalyst gave 4//-pyrrolo[3,2,l-(/]quinoline 270 (97H2395) (Scheme 48). 

The Parham cyclization of the iodinated imide 270 by BuLi in dry THF at —78°C afforded 1 lZ -hydroxy-l,3,4,6,7,l lZ -hexahydro[l,4]oxazine[3,4-a]iso-quinolin-4-one 258 (97JOC2080). Iodide-lithium exchange was faster then addition to the carbonyl group of imide 270 and intramolecular cyclization of the initially formed anion gave compound 258. 

Halocyclization of 8-(allylamino)quinolines 408 with I2 afforded 3-iodomethyl-2,3-dihydro-l//-pyrido[l,2,3-[Pg.318]

A mixture of 26 parts of 3-carbethoxy-6,7-methylenedioxy-4-hydroxy-quinoline, 16 parts of sodium hydroxide and 50 parts of dimethylformamide is heated at 70° to 75°C for 2 hours, then 31 parts of ethyl iodide is added over 1 hour with continued heating and stirring. After an additional 3 to 4 hours of heating (at 70° to 75°C) and stirring, the mixture is diluted with 500 parts of water, refluxed for 3 to 4 hours, acidified with concentrated hydrochloric acid and filtered to yield 18 to 22 parts of 1-ethyl-1,4-dihydro-6,7-methylene-dioxy-4-oxo-3-quinoline-carboxylic acid, MP 309° to 314°C (decomposes). The analytical sample from dimethylformamide melts at 314° to 316°C (decomposes). 

N— compounds used as acid inhibitors include heterocyclic bases, such as pyridine, quinoline and various amines. Carassiti describes the inhibitive action of decylamine and quinoline, as well as phenylthiourea and dibenzyl-sulphoxides for the protection of stainless steels in hydrochloric acid pickling. Hudson e/a/. refer to coal tar base fractions for inhibition in sulphuric and hydrochloric acid solutions. Good results are reported with 0-25 vol. Vo of distilled quinoline bases with addition of 0 05m sodium chloride in 4n sulphuric acid at 93°C. The sodium chloride is acting synergistically, e.g. 0-05m NaCl raises the percentage inhibition given by 0-1% quinoline in 2n H2SO4 from 43 to 79%. Similarly, potassium iodide improves the action of phenylthiourea . 

Methyl-4-phenyl thiazole-2)( 1-methyl quinoline-4)monomethine cyanine iodide, formation. 40... 

Indium metal reduces the pyridine ring in quinoline in aqueou sethanol solution.Samarium iodide (Sml2) reduces pyridine in aqueous THF ° and phenol in MeOH/KOH. ... 

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