    
|
 Helping San Diego, California and beyond since 1997 |
|
|
Helping San Diego, California and beyond since 1997 |
Click here and add this page to your favorites!
|
Encyclopedia Britannica - Main :: PYR-RAY |
|
|
QUINOLINE (Benzopyridine), C9H7N , an organic base first obtained from coal-tar in 1834 by F. Runge (Fogg. Ann., 1834, 31, p. 68), and later by C. Gerhardt by the distillation
oxide
CH2CH2 CH=CCl CH=CH C6H4\ C6114\\ -->C6H4 \ I i NHCO N =C.Cl N = CH and by the so-called "Skraup " reaction, which consists in oxidizing a mixture of aniline, glycerin and concentrated sulphuric acid, with nitrobenzene (Z. Skraup, Monats., 188o, 1, p. 316; 1881, 2, p. 141). This reaction is a very violent one, and its mechanism may probably be explained as follows: The glycerin is first converted into acrolein, which combines with the aniline to form acrolein-aniline, and this product is then oxidized by the nitrobenzene: C3HSO3>C3H4O (C6H5NH2)--sC6H5N: CH . CH: CH2-*C9H7N. The nitrobenzene may be replaced by arsenic acid, when the reaction proceeds much more quietly and a cleaner product is obtained (C. A. Knueppel, Ber., 1896, 29, p. 703). The Skraup reaction is a perfectly general one for primary amino-compounds; the halogen-, nitro- and oxy-anilines (aminophenols) react similarly, as do also the toluidines, naphthylamines, aminoanthracene, meta- and para-phenylene diamines, and orthoand y-aminoquinoline. Quinoline
quinoline
a y It is reduced by the action of zinc and ammonia ,/\/Ns to di-and tetra-hydroquinolines. A hexahydro- and a decahydroquinoline have been obtained m\/\N/a by heating tetrahydroquinoline with hydri- o odic acid and phosphorus to high temperatures (E. Bamberger, Ber., 189o, 23, p. 1138). Numerous substitution products of quinoline are known, and the positions in the molecule are generally designated in accordance with the scheme shown in the inset formula
standing
The oxvquinolines possess a certain importance owing to their relationship to the alkaloids. Those with the hydroxyl group in the benzene nucleus are prepared from the aminophenols by the Skraup reaction. Only two are known containing the hydroxyl group in the pyridine nucleus, namely, carbostyril (a-oxyquinoline), which is formed by the reduction of ortho-aminocinnamic acid with ammonium sulphide (L. Chiozza, Ann., 1852, 83, p. m8) or with ferrous sulphate and baryta, and kynurine (y-oxyquinoline), which is obtained by the action of nitrous acid on y-aminoquinoline (A. Claus and H. Howitz, Jour. prak. Chem., 1894, 158, p. 232). It is also formed by the condensation of anthranilic acid with acetaldehyde (S. Niemeritowski, Ber., 1895, 28, p. 2811). They are both crystalline solids, the former melting when anhydrous at 199-200, and the latter at 52 C. Of the homologues of quinoline, the most important are quinaldine, lepidine, -y-phenylquinoline, and flavoline. Quinaldine (a-methylquinoline) is present in coal-tar; it may be prepared by condensing aniline with paraldehyde and concentrated hydrochloric acid (O. Doebner and W. v. Miller, Bet., 1881, 14, pp. 2812 et seq.). The reaction is a perfectly general one, for the aniline may be replaced by other aromatic amines and the aldehyde by other aldehydes, and so a large number of quinoline homologues may be prepared in this way. Quinaldine may also be obtained by condensing ortho-aminobenzaldehyde with acetone
acetone
The oxy derivatives of the quinoline homologues are best obtained from the aniline derivatives of 0-ketonic acids. At 110 C. aniline and acetoacetic ester condense to form anilido-acetoacetic ester, CH3COCH2CO.NHC6H5, which is converted by concentrated ' acids into a-oxy-y-methylquinoline (L. Knorr, Ann., 1886, 236, p. 73). On the other hand, at about 240 C., the amine and ester react to form 13-anilidocrotonic ester, CH3C(NHC6H5) : CHCOOC2H5, which yields -y-oxy-a-methylquinoline (M. Conrad
Numerous carboxylic acids of quinoline are known,' the most important of which are quinaldic, cinchoninic and acridinic acids. Quinaldic acid (quinoline-a-carboxylic acid) is produced when quinaldine is oxidized by chromic acid. It crystallizes in needles, which contain two molecules of water of crystallization, and melt at 156 C. When heated above the melting-point it loses carbon dioxide and yields quinoline. Alkaline potassium pernanganate oxidizes it to pyridine tricarboxylic acid (2.3.6). Cinchoninic acid (quinoline-y-carboxylic acid) is formed when cinchonine is oxidized by nitric acid, or by the oxidation of lepidine. It crystallizes from water in needles or prisms and in the anhydrous state melts at 253-254 C. Potassium permanganate oxidizes it to pyridine tricarboxylic acid (2.3.4). Acridinic acid (quinoline-a$-dicarboxylic acid) is formed when acridine is oxidized by potassium permanganate (C. Graebe and H. Caro , Ber., 188o, 13, p. 100). It crystallizes in needles, which are easily soluble in alcohol, and when heated above 13o C. lose carbon dioxide and leave a residue of quinoline-0-carboxylic acid.Isoquinoline, isomeric with quinoline, was first discovered in coal-tar in 1885 by S. Hoogewerff and W. A. v. Dorp (Rec. Pays Bas, 1885, 4, 125) ; its formula
distillation
quinoline wiIthorhydgH4 I Criodic acid (S. Gabriel, Bet., 1886, 19, pp. 1655, 2355): CHz-CO CH = C(OH) CfiH4CH=CCI CHCH Ce5H4 \CO- NH \C(OH): N C CI=NI > C6H41 \CH= It is also formed from isobenzalphthalide by the action of ammonia, followed by phosphorus oxychlorid-*eCanH ,d, reduction of the chlorinated product (S. Gabriel), CH= CC5H5 /CH= CC6H5 C6He < \CO - CO-NH CH= GC6H5 CH= C C,H6 >c6H.,I - sC,H9 I \CCI=N CH=Nl and from isocoumarin carboxylic acid by conversion into isocarbostyril on heating, and subsequent reduction by distillation with zinc dust (E. Bamberger, Bet., 1892, 25, p. 1138). It melts at 22-23 C. and boils at 240 C., and behaves in most respects similarly to quinoline. By oxidation with alkaline potassium permanganate it yields phthalic acid and cinchomeronic acid. Reduction by means of tin and hydrochloric acid gives a tetrahydro derivative. Numerous derivatives of isoquinoline are obtained in the de-composition of various vegetable alkaloids. Papaverine on fusion with alkalis yields a dimethoxyisoquinoline, whilst hydrohydrastinine, hydrocotarnine and the salts of cotarnine may be considered as derivatives of reduced isoquinoliaes (see OP1uM). End of Article: QUINOLINE (Benzopyridine), C9H7N If you wish, you can link directly to this article.
<a href="http://jcsm.org/StudyCenter/Encyclopedia/PYR_RAY/QUINOLINE_Benzopyridine_C9H7N.html"> QUINOLINE (Benzopyridine), C9H7N </a> |
|
|
(Previous) QUININE |
(Next) QUINONES |
Jesus Christ Saves Ministries, P.O. Box 70696, Pasadena, CA 91117JCSM is a 501(c)(3), non-profit organization. Copyright © 1997-present. |
Free & Cheap Cell
Phones |
Cheap Long Distance
Phone Service Carriers |
Talk America Local Phone Service
|
Ztel & MCI - Unlimited Long Distance
Compare
Cell Phone Plans & Companies |
International Calling Cards & Prepaid Phone Cards |
Voice Over IP Broadband Internet Phone
Service | Wireless
Phone Plans & Cheap Cell Phones
|
_____________________________________________________________________________
