See also, the discussion on p. 427.
3. Biochemical methods. In a series of similar compounds, such as amino acids
or certain types of steroids, a given enzyme will usually attack only molecules
with one kind of configuration. If the enzyme attacks only the L form of eight
amino acids, say, then attack on the unknown ninth amino acid will also be on
the L form.
4. Optical comparison. It is sometimes possible to use the sign and extent of
rotation to determine which isomer has which configuration. In a homologous
series, the rotation usually changes gradually and in one direction. If the
configurations of enough members of the series are known, the configurations
of the missing ones can be determined by extrapolation. Also certain groups
contribute more or less fixed amounts to the rotation of the parent molecule,
especially when the parent is a rigid system, such as a steroid.
5. The special X-ray method of Bijvoet gives direct answers and has been used
in a number of cases
See also, the discussion on p. 427.
3. Biochemical methods. In a series of similar compounds, such as amino acids
or certain types of steroids, a given enzyme will usually attack only molecules
with one kind of configuration. If the enzyme attacks only the L form of eight
amino acids, say, then attack on the unknown ninth amino acid will also be on
the L form.
4. Optical comparison. It is sometimes possible to use the sign and extent of
rotation to determine which isomer has which configuration. In a homologous
series, the rotation usually changes gradually and in one direction. If the
configurations of enough members of the series are known, the configurations
of the missing ones can be determined by extrapolation. Also certain groups
contribute more or less fixed amounts to the rotation of the parent molecule,
especially when the parent is a rigid system, such as a steroid.
5. The special X-ray method of Bijvoet gives direct answers and has been used
in a number of cases
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