The position of the amino groups in pararosaniline was determined by the work of H.
By the entrance of amino or hydroxyl groups into the molecule dyestuffs are formed.
Cystin (protein-cystin) or a-amino-,-thioglyceric acid " disulphide," (S.
Since it does not form an addition product with bromine, reduction must have taken place in one of the nuclei only, and on account of the aromatic character of the compound it must be in that nucleus which does not contain the amino group. This tetrahydro compound yields adipic acid, (CH 2) 4 (CO 2 H) 2, when oxidized by potassium permanganate.
The amino derivatives are stable bases which readily yield substitution derivatives when acted upon by the halogen elements.
The meta-nitrocompound, which is precipitated last, is then reduced, and the amino group so formed is replaced by the hydroxyl group by means of the Sandmeyer reaction.
By replacing the chlorine in the imido-chloride by an oxyalkyl group we obtain the imido-ethers, R C(OR') :NH; and by an amino group, the amidines, R C(NH 2): NH.
From meta-brombenzoicacid two nitrobrombenzoic ac i ds are obtained on direct nitration; elimination of the bromine atom and the reduction of the nitro to an amino group in these two acids results in the formation of the same ortho-aminobenzoic acid.
He assumed that if we have one atom 1 It is now established that ortho compounds do exist in isomeric forms, instances being provided by chlor-, brom-, and amino-toluene, chlorphenol, and chloraniline; but arguments, e.g.
The same increase accompanies the introduction of the amino group into aromatic nuclei.
The acid finds considerable use in organic chemistry, being employed to discriminate between the different types of alcohols and of amines, and also in the production of diazo, azo and diazo-amino compounds.
The mono-amino derivatives or eurhodines are obtained when the arylmonamines are condensed with orthoamino zo compounds; by condensing quinone dichlorimide or para-nitrosodimethyl aniline with monamines containing a free para position, or by oxidizing ortho-hydroxydiaminodiphenylamines (R.
When heated with concentrated hydrochloric acid the amino group is replaced by the hydroxyl group and the phenolic eurhodols are produced.
The fate of these inorganiccompounds has not been certainly traced, but they give rise later on to the presence in the plant of various amino acid amides, such as leucin, glycin, asparagin, &c. That these are stages on the way to proteids has been inferred from the fact that when proteids are split up by various means, and especially by the digestive secretions, these nitrogen-containing acids are among the products which result.
The other group attacks these peptones and breaks them down into the amino-acids of which we have spoken before.
It is frequently used as a reducing agent: in acid solutions it reduces ferric to ferrous salts, arsenates to arsenites, permanganates to manganous salts, &c., whilst in alkaline solution it converts many organic nitro compounds into the corresponding amino derivatives.
Lactic acid and alanine were shown to be oxyand amino-propionic acids respectively; glycollic acid and glycocoll, oxyand amino-acetic acids; salicylic and benzamic acids, oxyand amino-benzoic acids.
By the action of hydroxylamine or phenylhydrazine on aldehydes or ketones, condensation occurs between the carbonyl oxygen of the aldehyde or ketone and the amino group of the hydroxylamine or hydrazine.
Considering derivatives primarily concerned with transformations of the hydroxyl group, we may regard our typical acid as a fusion of a radical R CO - (named acetyl, propionyl, butyl, &c., generally according to the name of the hydrocarbon containing the same number of carbon atoms) and a hydroxyl group. By replacing the hydroxyl group by a halogen, acid-haloids result; by the elimination of the elements of water between two molecules, acid-anhydrides, which may be oxidized to acid-peroxides; by replacing the hydroxyl group by the group. SH, thio-acids; by replacing it by the amino group, acid-amides (q.v.); by replacing it by the group - NH NH2, acid-hydrazides.
It is necessary clearly to distinguish such compounds as the amino- (or amido-) acids and acid-amides; in the first case the amino group is substituted in the hydrocarbon residue, in the second it is substituted in the carboxyl group.
The amino group is more powerful than the hydroxyl, and the substituted amino group more powerful still; the repeated substitution of hydroxyl groups sometimes causes an intensification and sometimes a diminution of colour.
Wallach (Ann., 1900, 312, p. 171) has shown that the saturated cyclic ketones yield oximes which by an application of the Beckmann reaction are converted into isoximes, and these latter on hydrolysis with dilute mineral acids are transformed into acyclic amino-acids; thus from cyclohexanone, e-amidocaproic acid (e-leucine) may be obtained: CH2" C NOH C CH 2 CH 2 7: ?12?CH2 CH2 NH /CH2 CH2 C02H CH2', An ingenious application of the fact that oximes easily lose the elements of water and form nitriles was used by A.
CH(NH 2) ï¿½ Cooh, isoleucin, probably 0-aminocaproic acid, serin or a-amino-(-hydroxy propionic acid, aspartic acid or aminosuccinic acid, HOOCï¿½CH 2 ï¿½CH(NH 2)ï¿½Cooh, glutaminic acid or a-amino-n-glutaric acid,HOOCï¿½ (CH 2) ï¿½ CH(NH 2) ï¿½ Cooh, diaminoacetic acid, a-O-diaminopropionic acid, lysin.
CH(NH 2) ï¿½ Cooh, arginin or guanidine-a-amino-n-valerianic acid, (NH)(NH2)Cï¿½NHï¿½ (CH 2) 3 ï¿½CH(NH 2)ï¿½Cooh, ornithin or aa-diamino valerianic acid, ï¿½ (CH 2) 3 ï¿½ CH(NH 2) ï¿½ Coon, -(3-imidazol propionic acid, [[Hoocï¿½ Ch(Nh 2) ï¿½Ch 2 ï¿½ C: Chï¿½N:Chï¿½Nh]], proline or a-pyrrolidin carboxylic acid, [[Hoocï¿½ Ch.
Nucleic acid is at present of unknown constitution; decomposition products are: phosphoric acid, uracil or 2.6-dioxy-pyrimidin,1 cytosin or 2-oxy-6-amino-pyrimidin, thymin (nucleosin) or 2.6-dioxy-5-methyl pyrimidin hypoxanthin 1 or 6-oxypurin, xanthin or 2.6-dioxypurin, adenine or 6 amino-purin, guanine or 2amino-6-oxypurin, pentoses (l-xylose), laevulinic acid, ammonia, etc. The nucleic acids vary with the source of the proteids, there being considerable differences in chemical composition.
Chemically they resemble the albumins, being split up by acids or ferments into albumoses, peptones and amino-acids, forming salts, and giving N =C6 1 The pyrimidin ring is numbered 2C "C5.
Amino derivatives similarly result from thio-ureas and a-haloid ketones; the oxy derivatives from a-sulphocyanoketones by the action of caustic alkali; and the carboxylic acids from chloro-aceto-acetic ester, &c. and thioamides.
The orthocompound melts at Io 5° C. and boils at 218° C., the para-compound melts at 54° C. and boils at 230° C. Meta-nitrotoluene (melting at 16° C.) is obtained by nitrating acetparatoluidide and then replacing the amino group by hydrogen.
In a similar manner, formic acid and dicyanophenylhydrazine yields a phenyl-triazole carboxylic acid, in which the phenyl group may be nitrated, the nitro group reduced to the amino group, and the product oxidized to a triazole carboxylic acid, which, by elimination of carbon dioxide, yields the free triazole: HO 2 C C=N H02C C =N, NPh-> N :CH N :CH They also result when the acidylthiosemicarbazides are strongly heated, the mercapto-triazoles so formed being converted into triazoles on oxidation with hydrogen peroxide (M.
(-anthrol and anthranol give the corresponding amino compounds (anthramines) when heated with ammonia.
This followed from a study of the decomposition products, there being obtained hemipinic acid (CH 3 0) 2 C 6 H 2 (000H) 2, and a substance which proved to be co - amino - ethyl - piperonyl carboxylic acid, CH 2 O 2 :C 6 H 2 [[Cooh-Ch 2 Ch 2 Nh]] 2.
Diamines.-The diamines contain two amino groups and bear the same relation to the glycols that the primary monamines bear to the primary alcohols.
It is to be noted that only traces of the aromatic amines are produced by heating the halogen substituted benzenes with ammonia, unless the amino group be situated in the side chain, as in the case of benzylamine.
Concentrated nitric acid attacks them violently, producing various oxidation products, but if the amino group be "protected" by being previously acetylated, then nitro derivatives are obtained.
With substances prone to discolorization, as, for example, certain amino compounds, the operation may be conducted in an atmosphere of carbon dioxide, or the water may be saturated with sulphuretted hydrogen.
Oxamic acid, HO 2 C CONH 2, is obtained on heating acid ammonium oxalate; by boiling oxamide with ammonia; and among the products produced when amino-acids are oxidized with potassium permanganate (J.
The most important is naphthionic acid, I-amino-4sulphonic acid, produced by heating a-naphthylamine and sulphuric acid to 170-180° C. with about 3% of crystallized oxalic acid.
3, p. 319.) Ammonia finds a wide application in organic chemistry as a synthetic reagent; it reacts with alkyl iodides to form amines, with esters to form acid amides, with halogen fatty acids to form amino-acids; while it also combines with isocyanic esters to form alkyl ureas and with the mustard oils to form alkyl thioureas.
Paraquinones also combine with ammonia and with amines yielding amino-derivatives and hydroquinones.
It is a powerful reducing agent, and is frequently employed for this purpose in organic chemistry; thus hydroxy acids are readily reduced on heating with the concentrated acid, and nitro compounds are reduced to amino compounds, &c. It is preferable to use the acid in the presence of amorphous phosphorus, for the iodine liberated during the reduction is then utilized in forming more hydriodic acid, and consequently the original amount of acid goes much further.
Amino-azo Compounds may be prepared as shown above.
They are usually yellowish brown or red in colour, the presence of more amino groups leading to browner shades, whilst the introduction of alkylated amino groups gives redder shades.
Amino-azo-benzene, C6H5 N2 C 6 H 4 NH 2, crystallizes in yellow plates or needles and melts at 126° C. Its constitution is determined by the facts that it may be prepared by reducing nitro-azo-benzene by ammonium sulphide and that by reduction with stannous chloride it yields aniline and.
Position with respect to the amino group. In these cases it has.
As the hydroxyl groups in aurin correspond to the amino groups in pararosaniline, two of these in the latter compound must be in the para position.
The diazonium salts are characterized by their great reactivity and consequently are important reagents in synthetical processes, since by their agency the amino group in a primary amine may be exchanged for other elements or radicals.
The diazo group preferably going into the para-position to the amino group. When the para-position is occupied, the diazo group takes the orthoposition.
The esters of the aliphatic amino acids may be diazotized in a manner similar to the primary aromatic amines, a fact discovered by T.
Ortho-amino-benzoic acid, C 6 H 4 NH 2 000H (anthranilic acid), is closely related to indigo.
It may be synthetically prepared by the fusion of cymol sulphonic acid with caustic potash; by the action of nitrous acid on 1-methyl-2-amino-4-propyl benzene; by prolonged heating of 5 parts of camphor with r part of iodine; or by heating carvol with glacial phosphoric acid.
Experience has shown that such mono-derivatives as nitro compounds, sulphonic acids, carboxylic acids, aldehydes, and ketones yield as a general rule chiefly the meta-compounds, and this is independent of the nature of the second group introduced; on the other hand, benzene haloids, amino-, homologous-, and hydroxy-benzenes yield principally a mixture of the orthoand para-compounds.
Thus ortho-phenylene diamine yields the following products: N H N ./`N; Xn NZ In some cases oxidation of condensed benzenoid-heterocyclic nuclei results in the rupture of the heterocyclic ring with the formation of a benzene dicarboxylic acid; but if the aromatic nucleus be weakened by the introduction of an amino group, then it is the benzenoid nucleus which is destroyed and a dicarboxylic acid of the heterocyclic ring system obtained.
As a useful preliminary it is convenient to divide heterocyclic ring systems into two leading groups: (I) systems resulting from simple internal dehydration (or similar condensations) of saturated aliphatic compounds - such compounds are: the internal anhydrides or cyclic ethers of the glycols and thioglycols (ethylene oxide, &c.); the cyclic alkyleneimides resulting from the splitting off of ammonia between the amino groups of diaminoparaffins (pyrrolidine, piperazine, &c.); the cyclic esters of oxycarboxylic acids (lactones, lactides); the internal anhydrides of aminocarboxylic acids (lactams, betaines); cyclic derivatives of dicarboxylic acids (anhydrides, imides, alkylen-esters, alkylenamides, &c.).
Alkylated amino-azo-benzenes are also known, and are formed by the coupling of diazonium salts with alkylated amines, provided they contain a free para.
The third is also in the para position; for if benzaldehyde be condensed with aniline, condensation occurs in the para position, for the compound formed may be converted into para-dioxybenzophenone, C6H5CHO -)C6H5CH(C6H4NH2)2 - >C6H5CH(C6H40H)2 -->CO(C6H40H)2 but if para-nitrobenzaldehyde be used in the above reaction and the resulting nitro compound N02 C6H4 CH(C6H4NH2)2 be reduced, then pararosaniline is the final product, and consequently the third amino group occupies the para position.
36; De amino, 9).