Page:Encyclopædia Britannica, Ninth Edition, v. 5.djvu/588

Rh 576 CHEMISTRY [ORGANIC. less, oily liquid, having a peculiar odour ; it boils at 182 C., and solidifies at - 8 C. The replacement of the phenylic hydrogen by halogens gradually destroys the basic character of aniline. Thus, chloraniline, C 6 H 4 C1(NH 2 ), and dichlor- aniline, C 6 H 3 C1 2 (NH 2 ), form crystalline salts with acids ; but trichloraniline, C 6 H 2 C1 3 (NH 2 ), possesses no basic properties. By the action of the iodides of CJH^+j radicles upon aniline, the amido-hydrogen can be replaced by these radicles, giving rise to the formation of secondary and tertiary mcnamines containing different radicles, such, for example, as ethyl-aniline, (C 6 H 5 )(C.,H 5 )NH 7 produced by the action of C 2 H 5 I upon aniline, and subsequent treatment with KHO; ethyl-amyl-aniline, (C 6 H 5 )(C 2 H 5 )(C 5 H n )N, formed by the action of C 5 H U I upon ethyl-aniline, &c. These tertiary amines combine directly with C n H 2, t+1 I, producing stable iodides N(C 6 H 5 )(aH 2n+1 )(C M H 2M+1 )(C p H 2p+1 )I, which are not decomposed by KHO, but by the action of Ag 2 O and water are converted into alkaline hydroxides, analogous to NH 4 HO. It will be seen that the iodides of CH 2n+1 radicles can thus be employed to determine whether the amine is primary, secondary, or tertiary. When aniline hydrochloride and methyl alcohol are heated together in a sealed tube, the amido-hydrogen is partially or entirely re placed by methyl, giving rise to the formation of methyl and dimethyl-aniline hydrochlorides. When both atoms of amido-hydrogen have been thus replaced, if the heating is continued the phenylic hydrogen becomes replaced by methyl giving rise to dimethyl-toluidine and its homologues. This interesting intra-molecular substitution was discovered by Hofmann. The nature of the transformation will be seen from the following formulae : N(C 6 H 5 )(CH,)(CH 3 ) N[C 6 H 4 (CH )](CH 3 )(CH 3 ) Dimethylaniline. Dimethyltoluidine. N[C 6 H 3 (CH 3 ) 2 ](CH 3 XCH 3, Dimetliylxylidine. (The last atom of phenylic hydrogen does not appear to be removed by this reaction.) Nitrous acid acts upon aniline in a manner similar to its action upon the C n H 2n+1 primary monamines, converting it into the corresponding alcohol (phenol) : C 6 H 5 (NH 2 ) + HN0 2 = C 6 H 5 (HO) + OH 2 If the aniline is diluted with alcohol, however, intermediate products are formed + HN0 2 - C 12 H n N 3 + 20H 2 Azodiphenyldiamine. HNO 2 = C 12 H 8 N 4 + Diazo-diphenyldiamine. 20H 2 . C 12 H n N 3 Azodiphenyldiainine. If salts of aniline are employed, salts of these azo-derivatives are produced. Aniline combines with aldehydes with the elimination of water, producing pkenaldines : 2C 6 H 5 NH 2 + CH 3 .COH - OH 2 = C 14 H 16 N 2 . Paraniline a polymeride of aniline, having the composition C 12 H 14 N 2 , is known. Allied to the present group of amines is naphthalidine, C 10 H T (NH 2 ), produced by the reduction of nitronaphtha- lene. Natural Alkaloids. These compounds are organic bases existing already formed in plants. With the exception of piperwZwie (CgHjjN) and conine, which are secondary mona- mifles, the alkaloids at present known are tertiary com pounds. The following are some of the more important of this group of amines : - From the ba/rJc of species of Cinchona. Quinamine C 20 H 06 X 2 2 Pay tine C 21 H 24 N 8 O Quinine C 2 oH 24 N 2 2 Cinchonine C 20 H 24 N 2 O Morphine C 17 H 19 N0 3 From Opium. ,NO. 23 N0 7 H 01 NO, Codeine C 3 8 H Narcotine C 22 H Thebaine C 19 Papaverine C 20 H 2 jN0 4 Narceine C 23 H 29 N0 9 Hydrocotarnine. . . C 12 H 15 N 3 Pseudoinorphine. .C 17 H 19 N0 4 Codamine C 20 H 25 NO 4 Lanthopine C 23 H 25 N0 4 Laudanine 20 H 25 N0 4 Meconidine C 21 H 23 N0 4 Cryptopine C 21 H 23 N0 5 Protopine C 20 H 19 N0 5 From various Plants. Strychnine C 21 H 22 N 2 2 Brucine C 2:j H 26 N 2 4 Nicotine C 10 H 14 N 2 Conine C 8 H 15 N Sparteine C 10 H 26 N&quot; 2 Atropine C 17 H 23 N0 3 Aconitiue C 30 H 47 N0 7 Theobromine C 7 H 8 N 4 2 Caffeine andTheine..CoH in N,09 From Nux Yoinica, St Ignatius s bean, &c. From tobacco. From hemlock. From broom. From nightshade From monkshood: From cocoa seeds. From tea, cofl ee, Ilex para- guensis, &c. The constitution of the radicles contained in these various bases has not hitherto been made clear. Among the cinchona alkaloids of which the valuable medicine quinine is a member some interesting cases of physical isomerism occur. Many bases have been obtained by the action of reagents on the opium alkaloids. A base isomeric with conine has been prepared artificially by heating normal butyl aldehyde with an alcoholic solution of ammonia so as to produce dilufyraldine : 2C 3 H 7 .COH + IS T H 3 - OH 2 = C 8 H ir NO, and then submitting this latter substance to dry distillation : C 8 H 1V NO - OH 2 = C 8 H ]5 N. Bases from varioits Sources. The following are a few bases of animal origin : Creatine C 4 H 9 N 3 2 Creatinine C 4 H 7 N 3 Guanine C 5 H S 1S T 5 Xanthine C 5 H 4 N 4 2 Sarcine C 5 H 4 X 4 From juice of raw flesh. From creatine by the action of strong acids. From guano and pancreatic juice of mammalia. From guanine and urinary cal culi. From flesh of vertebrata. Many bases have been obtained by the destructive distillation of organic matter containing nitrogen. These compounds are tertiary monamines: Chinoline .. , ..C a H 7 N | By distilling cinchona alkaloids a | with caustic potash. Pyrrol C 4 H 6 N From coal-tar and animal oil. Others are derived from oil produced by the destructive distillation of bones, &c., and coal-tar naphtha : Pyridine C 5 H 5 N Picoline C 6 H 7 N Lutidine C 7 H 9 N Collidine .. ...C.H^X C re H 2n Br 2 R&quot; dibromide. Parvoline ........... C 9 H 13 N Coridine ....... ...... C 10 H J5 N Eubidine ............ C U H 17 N Yiridine .............. C 12 H 19 N Hydramides (p. 568), when boiled with potash solution, are converted into basic compounds. Amarine, C 21 H 18 N 2 , is a substance formed in this manner from hydrobenzamide. Diamines are formed by reactions analogous to those employed in the preparation of monamines : 2NH 3 = N 2 (C B H 2n )H 4 .2HBr R&quot;-d~iamine dihydrobromide. As in the preparation of monamines, secondary diamines are at the same time formed : 2C n H 2n Br 2 + 4NH 3 = N 2 (C n H 2rl ) 2 H 2. 2HBr + 2NH 4 Br. R&quot; dibromide. Di-R&quot;-diamine dihydrobromide. The action of KHO upon the primary diamine dihydro bromide is different from its action upon the corresponding monamine compound, inasmuch as an oxide of the diamine is formed : N 2 (C n H 2n )H 6 Br 2 + 2KHO = N 2 (C n H 2n )H 6 O + 2KBr + OH 2 R&quot;-diamine dihydro- R-&quot;diammonium oxida bromide. The diamines corresponding to benzene and its homo logues are produced by the reduction of the dinitro- derivatives of the respective hydrocarbons C 6 H 4 (N0 2 ) 2 Dinitrobenzene. 6H = C 6 H 4 (NH 2 ) 2 Phenylene diamine. 40H