Coniine and the Hemlock Alkaloids

 

 

 

 

Introduction

The hemlock alkaloids are (+)-coniine, N-methylconiine(+)-conhydrine,  psuedoconhydrine and g-conice´ne.  They are all  monocyclic alkaloids.  Of these coniine is the most important and most toxic.

(+)-Coniine is a liquid, boiling point 166o - 187oC, [a]D +15.7o, and is the main constituent of oil of hemlock.  Socrates drunk this liquid when he was condemned to death in 399 B.C. and it is this which gives rise to the material's notoriety.  It was also the first alkaloid to be synthesised.  The structure of coniine,  2-propylpiperidine, is shown below:

click for 3D structure

The four remaining hemlock alkaloids are less important.  They are Conhydrine, 1-piperidin-2-yl-propan-1-ol,   g-conice´ne, 2-propyl-2,3,4,5- tetrahydropyridine,  N-methylconiine and psuedoconhydrine.  Their structures are shown below:

click for 3D structure click for 3D structure click for 3D structure click for 3D structure

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