Page:Outlines of Physical Chemistry - 1899.djvu/111

 Two Asymmetric Carbon Atoms

C b — CJ f I ^ our ^ 2 ) ac ^ ve modifications are possible. ~ rue/-" ^or * ne simpler type Cabc — Gabc the

��(Xc — GdJ)

��forms 2 and 3 are identical and inactive.

��Three, Asymmetric Carbon Atoms

Ga h c— Gd'— Gf g h\ Ca b c-Cd<— Cf g h Ca b c—Cd e —Cf h Ga b c—Cd e —Cf g h Ga b c—Cd e --Cf g h Gckc— Cd e — Gf g h Catc—Cde—Cf'h Ga h c—Gd e —Gf g h!

��Eight (2 3 ) active modifications v are possible.

��A few examples may now be quoted in support of the theory the outlines of which have just been given.

Substances with One Asymmetric Carbon Atom. — We foresee two active modifications and one inactive (by mixture of the active ones).

Ethylidene-lactic acid :

ch 3 — Ghoh— co 2 h

We know :

1. the inactive acid : ordinary lactic acid.

2. the dextro-rotatory acid. This exists in the substance of the muscles. It can be artificially prepared by cultiva- ting Penicillium glaucum in fermentation ammonium lactate; the laevo-rotatory modification is destroyed in greater quantity, causing the residue to become dextro- rotatory.

8. The IcBVO-r'otatory acid. This is produced by the action of a certain bacillus, found in some Hungarian wells, on cane sugar. It can also be obtained by crystallisation of the strychnine salt of the inactive acid, when the salt of the laevo-rotatory form separates out first.

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