The present experiments were undertaken according to the same reaction theory as the partial reduction of pyridine derivatives which are the active group of cozymase and coferment reported at the General Meeting of the Pharmaceutical Society of Japan in 1940. The compounds taken up were quinoline methiodide, quinaldine methiodide and lepidine ethiodide which are part of the structure of cyanine dyestuffs. According to the equation
Na
2S
2O
4+2H
2O→2NaHSO
3+H
22NaHSO
3+2NaHCO
3→2Na
2SO
3+2H
2O+2CO
2the amount of CO
2 here formed was determined volumetrically by Warburg's manometer, and following results were obtained.
1) Approximately 1mol. H
2 was absorbed by 1mol. quinoline methiodide.
2) Approximately 2mol. H
2 was absorbed by 1mol. quinaldine methiodide.
3) Approximately 1mol. H
2 was absorbed by 1mol. lepidine ethiodide.
The reduction products of (1) and (2) were experimentally prepared as the known
N-melhyl-1, 2, 3, 4-tetrahydroquinoline,
N-methyl-
o-dihydroquinaldine and
N-methyl-1, 2, 3, 4-tetrahydroquinaldine. Comparative studies showed that quinoline methiodide formed a dihydro compound if treated with hydrosulfite in NaHCO
3 solution, although it was difficult to decide whether the compound was an ortho or a para substance. It was proved that quinaldine methiodide was reduced to
N-methyl-1, 2, 3, 4-tetrahydroquinaldine, via dihydro compound by the action of hydrosulfite in NaHCO
3 solution. Lepidine ethiodide reacted very slowly, the determination having made solely by manometer although it is assumed that it forms a dihydro compound.
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