* * * * *

SYNTHESIS OF THE ALKALOIDS.

In the note on the constitution of alkaloids in a recent issue, we referred more especially to what we may term the less highly organized bases.  Most of our knowledge, as we now have it, regarding such alkaloids as muscarine and choline has been acquired during the past dozen years.  This is not exactly the case with the higher groups of alkaloids—­the derivatives of pyridine and quinoline.  It so happens that the oldest alkaloids are in these groups.  They have, almost necessarily, been subjected to a longer period of attack, but the extreme complexity of their molecules, and the infinite number of differing parts or substances into which these molecules split up when attacked, are the main cause of the small progress which has been made in this department.  All, however, yield one or more bodies or bases in common, while each has its distinctive and peculiar decomposition product.  For example, cinchonine and quinine both afford the basic quinoline under certain conditions, but on oxidation of cinchonine, an acid—­cinchoninic acid (C_{10}H_{7}NO_{2})—­is the principal body formed, while in the case of quinine, quininic acid (C_{10}H_{9}NO_{3}) is the principal product.  The acquirement through experiment of such knowledge as that is, however, so much gained.  We find, indeed, that obstacles are gradually being cleared away, and the actual synthetic formation of such alkaloids as piperidine and coniine is a proof that the chemist is on the right track in studying the decomposition products, and building up from them, theoretically, bodies of similar constitution.  It is noteworthy that the synthesis of the alkaloids has led to some of the most brilliant discoveries of the present day, especially in the discovery of dye stuffs.  Many of our quinine substitutes, such as thalline, for example, are the result of endeavors to make quinine artificially.  If there is romance in chemistry at all, it is to be found certainly in this branch of it, which is generally considered the most uninteresting and unfathomable.  We may take piperidine and coniine as examples of the methods followed in alkaloidal synthesis; these are pyridine bases.  Pyridine has the formula C_{5}H_{5}N, that is, it is benzene with CH replaced by N. The relationship between these and piperidine is seen in the following formulae: 

CH            N                NH
/  \          /  \             /  \
HC    CH      HC    CH     H_{2}C    CH_{2}
|    |        |    |           |    |
HC    CH      HC    CH     H_{2}C    CH_{2}
\  /          \  /             \  /
CH            CH               CH_{2}

    (Benzene,) (Pyridine,) (Piperidine,)
    (C_{6}H_{6}) (C_{5}H_{5}N) (C_{5}H_{11}N)