4-Chloro-5-hydroxytryptamine

When 5-HT is oxidized at potentials equal to or more positive than Ep for peak Ila only a single product, tryptamine-4,5-dione (B), is initially formed. This indicates that at such potentials the primary oxidation product, radical 1, is oxidized to quinone imine 6 more rapidly than it can dimerize. At peak Ila potentials 4-chloro-5-hydroxytryptamine (C) is oxidized to dione B. It is probable that this process involves oxidation of C (2e", 2H ) to the 4-chloro quinone imine 7 which is attacked by water with loss of HCl to yield dione B (Figure 8). 

Suzuki, T., Imanishi, N., Itahana, H., Watanuki, S., Miyata, K., Ohta, M., Nakahara, H., Yamagiwa, Y., and Mase, T., Novel 5-hydroxytryptamine 4 (5-HT4) receptor agonists. Synthesis and gastropro-kinetic activity of 4-amino-V-[2-(l-aminocycloaIkan-l-yl)ethyl]-5-chloro-2-methoxybenzamides., Chem. Pharm. Bull., 46, 1116, 1998. 

ACh acetylcholine 2-methyl-5>Hl 2-methyl-5-hydroxytryptamine 3>chloro-PBG l-(3-chloro-phenyl)-biguanide 5-HT 5-hydroigrtryptamine Azasetron N-(l-azabicyclo[2.2.2.]oct-3-yl)-6-chloro-4-methyl-3-oxo-3,4-dihydro-2H-l,4 -benzoxazine-8-carboxamide Batanopride 4-amino-5-chloro-N-[2-([Pg.258]

Attempts to extend the reaction to the syntheses of 5-chloro and 5-bromo derivatives have led us to discover that treating 1-hydroxytryptamines simply with aqueous hydrogen halides at room temperature is sufficient to meet our end (99H2815). 

When 54 is treated with hydrogen halides, rapid nucleophilic substitution reactions take place within 10 min at room temperature (Table 7). In the reaction with HCl/f-BuOH, 5-chloro- (131, 60%), 7-chlorotryptamines (132, 4%), and tryptamine (55, 3%) are produced. The reaction of 54 with HBr/f-BuOH affords 5-bromo- (36), 7-bromotryptamines (59), and tryptamine (55) (entry 1). In the same reaction, the employment of formamide as a solvent dramatically changes the reaction pathway to yield 1-hydroxytryptamine (52) as a sole product (entry 2) [24]. 

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