1) Methadone exists as a racemic mixture of two enantiomers in a 1:1 ratio, with the dextrorotary form having potent antitussive properties but lacking analgesic effects, while the levorotary form is twice as effective an analgesic. 2) Methadone can be chemically synthesized from nitrile using the Kolbe synthesis and diphenylacetonitrile, and a racemic mixture can be obtained using tartaric acid. 3) Oxazolidinedione forms the core structure of several anticonvulsant drugs, including paramethadione which is associated with fetal trimethadione syndrome.

1. Methadone, Carbamazepine
and oxazolidinedione
By
Dr. Nidhi Gupta
M.M. University, Mullana, Ambala, India

2. Methadone synthesis
• Methadone is a chiral substance, therefore, presents itself as a
racemic mixture of two enantiomers in mutual relationship of 1:1,
respectively the levorotatory form of methadone (L)-methadone and
dextrorotary shape (D)-methadone: the dextrorotatory form
possesses potent antitussive properties, but is almost completely
devoid of analgesic properties; the levorotary one is about two times
more effective as an analgesic, than the racemic form of methadone.

3. Methadone synthesis

4. Methadone synthesis contd.
• The process of chemical synthesis of racemic methadone is obtained
from the nitrile with the synthesis of Kolbe and with the
diphenylacetonitrile. One can obtain the formation of a racemate L-
(+) with the tartaric acid.

6. Oxazolidinedione anticonvulsants
• Oxazolidinedione is a heterocyclic chemical compound that forms the
core structure of a variety anticonvulsant drugs including:
• Paramethadione is an anticonvulsant in the oxazolidinedione class. It
is associated with fetal trimethadione syndrome, which is also known
as paramethadione syndrome.
Paramethadione

7. 2,4-oxazolidinedione Dimethadione

8. Methyldopa structure
Methyldopa