1,2,3,4-Tetrahydroquinoline Derivatives and its Significance in Medicinal Chemistry

Headnote

ABSTRACT:

1,2,3,4-Tetrahydroquinoline derivatives are the most important class of compounds in the pharmaceutical and agrochemical industries and play important role in the field of medicinal chemistry with so many Pharmacological activities such as anti-cancer, anti-diabetic, anti-parasitic, anti-inflammatory, anti-oxidant, adrenergic, anti-HIV, antialzheimer, anti-hyperlipidemic, activities. The tetrahydroquinoline ring containing system found in numerous biologically active natural products and pharmacologically relevant therapeutic agents and very common structure motif. Because of the significance of these scaffolds in medicinal chemistry, the development of some potent and important amalgams continues to be a very active field in development of a promising target for new drug development. 1,2,3,4-Tetrahydroquinoline is one such important part of pharmacophore and having different pharmacological activities. Here we have introduced different 1,2,3,4-tetrahydroquinoline derivatives which possess different biological activities depends on its types and position of substituted functional groups. This review is summarized to know about the chemistry of different 1,2,3,4-tetrahydroquinoline derivatives along with their pharmacological activities.

KEYWORDS: 1,2,3,4-Tetrahydroquinoline, anti-cancer, anti-cancer, anti-diabetic, anti-parasitic, antiinflammatory.

INTRODUCTION:

Rapid recent developments in the chemistry of 1,2,3,4tetrahydroquinolines has prompted us to review and classify all their major synthetic methods currently in use. We restrict this report to 1,2,3,4-tetrahydroquinolines in which the C-2, C-3, and C-4 atoms are all sp3" hybridized.1Tetrahydroquinolines is one such important molecular scaffold in medicinal chemistry which serves as an inert carrier for holding various biologically activity. Substituted tetrahydroquinolines are the core structures in many important pharmacological agents and drug molecules, such as anti-arrhythmic and cardiovascular agents, anti-cancer drugs, immunosuppressants, ligands for 5-HT1A and NMDA receptors.2

The greatest interest in 1,2,3,4-tetrahydroquinolines is due to their biological activities such as anti-cancer, antidiabetic, anti-parasitic, anti-inflammatory, anti-oxidant, adrenergic, anti-HIV, anti-alzheimer.

Several of these compounds are naturally occurring like 2Methyl1,2,3,4-tetrahydroquinoline is present in human brain. In fact 2-substituted tetrahydroquinoline Oxamniquine has been used in clinic to treat Manson's schistosomiasis since 1979.2Dynemycin, a natural antitumor, antibiotic, has a complex structure built on the basis of tetrahydroquinoline system.

Synthesis of 1,2,3,4-tetrahydroquinolines moiety:

Reduction of the heterocyclic ring in quinolones

Direct reduction of the heterocyclic ring can still be the best option for the preparation of tetrahydroquinolines through hydrogenation of quinolones over platinum dioxide in methanol proceeds well under very mild conditions, at room temperature and under atmospheric pressure (Fig.1).1

Conversions of quinolones to 1,2,3,4-tetrahydroquinolines...