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IT KINK BASES. 187
I IX—CO
I I
For example, uric acid, OC —NH\ ,
is 2, P>, S-trioxvpurine; adenine,
I II
>co
HN-C—XJT
N=CHN, •
IIX-CO
II M.
HC C
—
XI k , is G-aminopurine, and heteroxanthine, OC C—X.CH3 , is
H II
>CH I II
>CH
X -(
’
X^ II x-c-x/tn
7-methyl-2, 6-dioxypurine, etc.
The starting-point used by Fischer for the synthetical preparation of the
purine bases was 2, 6, S-triehlorpurine, which is obtained, with N-oxy-2, (i-dichlor-
purine as an intermediary product, from potassium urate and phosphorus oxychlo-
ride.
The purine bodies or alloxuric bodies, found in the animal body or its
excreta are as follows: Uric acid, xanthine, heteroxanthine, \-methylxan-
paraxanthine, guanine, epiguanine, hypoxanthine, episarkine,
adenine. The bodies theobromine, theophylline, and caffeine, occurring in
the vegetable kingdom, stand in close relation to this group.
The composition of the purine bodies most important from a physio-
logical standpoint is as follows:
Uric acid, C5H4X4O3 2, 6, 8-trioxypurine
Xanthine C5H4X4O2 2, 6-dioxypurine
l-methylxanthine, C6H6X402 1-methyl "
Heteroxanthine, C6 H6 X402 7 " "
Theophylline, C7 H8X4()2 1, 3-dimethyl
Paraxanthine, C7H8X4O2 1.7- "
Theobromine C7H8X4O2 3, 7-
Caffeine, C8 H,oX402 1,3, 7-trimethyl
Hypoxanthine, Cs^X^O 6-oxypurine
Guanine C5 H5 X5 2-amino " "
Epiguanine, C6 H7 X5 7-methyl " " " "
Adenine CsHsX’j 6-aminoourine
Episarkine, C4H6X30(?)
After Salomon !
had shown the occurrence of xanthine bodies in
young cells, the importance of the purine bases as decomposition prod-
ucts of cell nuclei and of nucleins was shown by the pioneering researches
of Kossel, who discovered adenine and theophylline. In those tissues
in which, as in the glands, the cells have kept their original state, the
purine bases are not found free, but in combination with other atomic
groups (nucleic acids). In such tissues, on the contrary, as in muscles,
which are poor in cell nuclei, the purine bases are found in the free state.
Since the purine bases, as suggested by Kossel, stand in close relation-
ship to the cell nucleus, it is easy to understand why the quantity of
these bodies is so greatly increased when large quantities of nucleated
1
Sitzungsber. d. Bot. Verein der Provinz Brandenburg, 1880.
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