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Functional Chemical Groups that May Likely Become a Source for the Synthesis of Novel Central Nervous System (CNS) Acting Drugs.

INTRODUCTION
Central Nervous System (CNS) disorders are on increase perhaps due to genetic, enviromental, social and dietetic factors. Unfortunately, a large number of CNS drugs have adverse effects such as addiction, tolerance, psychological and physical dependence. In view of this, literature search was carried out with a view to identify functional chemical groups that may serve as lead molecules for synthesis of compounds that may have CNS activity.


METHODS
The search revealed that heterocycles that have heteroatoms such as nitrogen (N), sulphur (S) and oxygen (O) form the largest class of organic compounds. They replace carbon in a benzene ring to form pyridine. Compounds with furan, thiophene, pyrrole, pyridine, azole, imidazole, indole, purine, pyrimidine, esters, carboxylic acid, aldehyde, pyrylium, pyrone, pyrodine, barbituric acid, barbiturate, quinoline, quinolone, isoquinolone, coumarin, alkylpyridine, picoline, piperidine, diazine, carboxamide, flavonoid glycoside, oxindole, aminophenol, benzimidazole, benzoxazole, benzothiazole, and chromone chemical groups among others may have CNS effects ranging from depression passing through euphoria to convulsion.


RESULTS AND CONCLUSION
Examples of the compounds with the functional groups include but not limited to coal tar, pyridostigmine, pralidoxime, quinine, mefloquine, pyrilamine, pyronaridine, ciprofloxacin and piroxicam. A number of them can undergo keto-enol tautomerism. Chiral amines may be used for derivation of chiral carboxylic acids which are components of tautomers. Some tautomers may cause parkinsonism and Stevens Johnson syndrome.