Pharmacological studies on tandamine hydrochloride, a potential heterocyclic antidepressant

Update on thiopyran-fused heterocycle synthesis (2013-2024)

Thiopyrans and their fused derivatives have significant synthetic relevance owing to their biological importance and occurrence in natural products. The current article provides an overview of synthetic strategies employed for the construction of thiopyran-fused heterocycles. In particular, this article discusses synthetic methods for the fusion of thiopyran with heterocycles such as indole, quinoline, pyrimidine, pyridine, thiophene, chromene, oxazole, pyrazole, pyran and furan and covers the literature from 2013 to 2024. The most common precursors for thiopyrano[2,3-b]indoles, thiopyranoquinolines and thiopyranothiazoles are indoline-2-thione, 2-mercaptoquinoline-3-carbaldehyde and thiazolidinone, respectively, and various reactions involving these are described in detail here. Asymmetric syntheses of thiopyranoindoles achieved using chiral catalysts based on thiourea, proline and metal complexes are also included. The biological activity associated with some compounds is also discussed.

Lithium-Promoted Cycloaddition of Indole-2,3-dienolates and Carbon Disulfide as a One-Pot Route to Thiopyrano[4,3-b]indole-3(5H)-thiones

A new approach for the annulation of a thiopyrane ring to an indole core under mild conditions was developed. Treating 2-methyl-3-acylindoles with lithium diisopropyl amide leads to the elimination of a proton from the 2-methyl group. The lithium indole-2,3-dienolates obtained were found to react with CS₂ to give the corresponding thiopyrano[4,3-b]indole-3(5H)-thiones. The mechanism represents a stepwise addition through ion-pair formation, according to PCM/B3LYP/6-311++G**, PBE1PBE/6-311++G**, and MP2//HF/6-311++G** quantum chemical calculations. AIM calculations revealed the essential role of the Li atom at all stages of the process.

Effect of acute and chronic treatment of tandamine, a new heterocyclic antidepressant, on biogenic amine metabolism and related activities

The effects of tandamine, a clinically effective heterocyclic antidepressant, administered either acutely (10 mg/kg i.p.) or chronically (10 mg/kg i.p. daily for 21 days) on biogenic amine uptake and metabolism in the rat were determined and a comparison with desipramine was made. Tandamine, similarly to desipramine, blocked norepinephrine (NE) uptake in rat brain and heart following both acute and chronic administration. No effect of tandamine on dopamine (DA) or serotonin (5-HT) uptake was observed. Both drugs lowered endogenous brain NE when given chronically but not acutely. In contrast, no such effect on brain DA and 5-HT or heart NE was observed. Tandamine, like desipramine, administered chronically prior to an intraventricular injection of 3H-NE, produced increases in the decline of 3H-NE as indicated by decreased 3H-NE with increased levels of 3H-normetanephrine in brain stem of rats, suggesting an increased turnover of NE. No such effect was observed following acute treatment. Both drugs increased the behavioural effects of L-Dopa following and acute oral administration, with tandamine appearing superior to desipramine at the lower dose examined (10 mg/kg). Tandamine was 57--833 times less effective in binding to rat brain muscarinic receptors than desipramine, imipramine, butriptyline and amitriptyline, respectively. Thus, tandamine affects biogenic amine mechanism following either acute or chronic administration in a fashion similar to desipramine, but unlike desipramine, it exhibits relatively little anticholinergic properties, a further indication of the potential use of tandamine in the treatment of human depression, particularly where an increase in drive is desired.