ORGANIC BASES. Under the definition of the term BASE, the organic bases—or the bases derived from animals and vegetables—have been alluded to. The source, preparation, properties, &c., of these nature bases or alkaloids are detailed under their respective names, [CINCHONA, ALKALOIDS OF; CON1NE; NICOTINE; Nux VOIIICA, ALKA LOIDS OF; OPIUM, ALKALOIDS OF, &c.] The artificial organic bases have not been so fully described, and indeed in most cases only curso rily noticed in the article on the body from which they are derived. The present article will therefore be devoted to a description of the modes of formation and general properties of the artificial organic bases, prefaced by a brief review of the probable constitution of the organic bases generally.
A prominent characteristic of organic bases is the presence of nitro gen ; they all contain nitrogen. The nitrogenous principles in animals are, of course, directly or indirectly obtained from vegetables ; and the nitrogen in vegetables is known to be derived from ammonia. Nearly all artificial organic bases are actually built up from ammonia ; and, moreover, artificially or naturally formed, they all retain the character of basicity, which is the chief chemical property of ammonia. Follow ing then such strong presumptive evidence, chemists have of late years referred the organic bases to the simple typical body ammonia, and have in most cases succeeded in showing how they are constructed upon, or at all events derived from, the type NH, (amines). Berzelius was the first to suggest that the basic character of the alkaloids was inti mately connected with ammonia. To the prophetic sagacity of Liebig, however, are we indebted for the idea that they were derivatives of ammonia ; that they were, in fact, amidogen bases or ammonia (NH,) in which an equivalent of hydrogen is replaced by an electropositive radical. Following out this idea Wurtz succeeded in obtaining several such bodies; but it is chiefly to the remarkable and laborious investi gations of Dr. Hofmann that we are indebted for the very complete knowledge which we possess of this interesting class of organic com pounds.
Amines, is a frequent collective title of the organic bases that are derivatives of NH,. The amines may be :—l. Monamines; 2. Dia mines ; 3. Triamines ; 4. Tetramines ; or, 5. l'entamines, according as they seem to be constructed upon a single, double, triple, quadruple, or quintuple atom of NH,.
I. Monamines. This class is constructed upon a single typical atom of ammonia, namely, H N. Primary mom/mines contain only one of the three atoms of hydrogen (H) replaced by a radical (It); their It general formula is therefore 11 N. Secondary monamines contain
two atoms of radical, thus, It N; and moreover the radicals may be similar or different ones. Here we get the first glimpse, and a very faint one, too, of the inconceivable numbers of organic bases that possibly exist ; for of twenty radicals the first may be occupying the place of one equivalent of hydrogen in a secondary monamine, while each of the remaining nineteen successively occupy the place of the other equivalent of hydrogen, a new organic base being each time produced. Similarly the second of the twenty radicals may be keeping its place, while the remaining eighteen are consecutively introduced, and another batch of bases formed ; and thus with only twenty simple radicals nearly two hundred secondary monamine bases may be ob tained. But there are many mere than twenty radicals, and each successive one would of course introduce a greater number of changes, and produce, therefore, a greater number of compounds than its pre decessor. each simple radical possesses its own chlorine, bromine, iodine, peroxide of nitrogen, &c., derivative, and of course each of these might keel) its place in a secondary monamine, while innumerable changes were being rung upon the second radical. Indeed it is useless endeavouring to pursue these calculations farther; we have only got into the second of twelve classes, and already view such a number of organic bases as would defy the powers of the most zealous experimenter to produce and examine. When, again, it is remembered that the next class, the tertiary monamiucs N must contain a far It greater variety, an indistinct notion can be obtained of the number of changes that may take place in the still higher classes. Tho general formula) of the taonamines are obviously six :— been termed—containing a diatomic radical (R") In the place of two equivalents of hydrogen, e.g., con lamina (cosine) N.
c. Tertiary monamines containing a diatomic radical, as, for instance, tnethyl-conykunine (methyl-conine) } N. f. Tertiary mona mines containing a triatomic radical in the place of three equiva lents of hydrogen, examples of them are seen in picoline (C„11,)"'1 N, and leueoline N.
2. Piamines. These bodies are formed upon the type of two atoms H, H H of ammonia, or diammonia- 11, N„ or H H N N. A great number 11, If H of organic bases belonging to t iis type have already been formed; not only primary, secondary, and tertiary, but belonging to intermediate divisions, the construction of which will be readily understood on looking over the annexed list of the general formulae of diamines:— R