Compounds with a Single Heterocyclic Atom

Dopamine, the free catechol corresponding to (1-1), plays an important role as a neurotransmitter, particularly in the CNS. The synthesis of a dopamine-related sedative agent starts with the condensation of homoveratramine (1-1) with styrene oxide (1-2) to afford the carbinol (1-3). Treatment of that product with a strong acid leads to an attack on the electron-rich aromatic ring by the resulting carbocation there is thus obtained the benzazocine (1-4). The secondary amine is then methylated by reaction with formaldehyde and formic acid to yield trepipam (1-5) [1]. 

Strategies for Organic Drug Synthesis and Design, Second Edition. By Daniel Lednicer Copyright 2009 John Wiley Sons, Inc. 

Dopamine itself has long been used as an inotropic agent in acute treatment of congestive heart failure. Both that compound and a number of its analogues have a positive action on contractility as a consequence of their adrenergic agonist activity. 

The addiction to nicotine that makes smoking withdrawal so difficult for many is believed to be mediated by a subset of nicotinic acetylcholine receptors. A bridged bicylcic aryl-benzepine that acts as a partial agonist at those sites is now approved as an aid for tobacco smoking withdrawal. The synthesis starts with the known ben-zonorbomenone (3-1). Treatment of that compound with selenium dioxide leads to the oxidation of the carbon adjacent to the carbonyl group and thus the formation 

SEVEN-MEMBERED HETEROCYCLIC RINGS FUSED TO BENZENE 

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