Unexpected Formation of 3-Substituted 1,2,3,4-Tetrahydroisoquinolines during Tosylation of N,N-dibenzylaminols

Tetrahydroisoquinolines - an updated patent review for cancer treatment (2016 - present)

INTRODUCTION

Cancer is a prominent cause of death globally, triggered by both non-genetic and genetic alterations in genes influenced by various environmental factors. The tetrahydroisoquinoline (THIQ), specifically 1,2,3,4-tetrahydroisoquinoline serves as fundamental element in various alkaloids, prevalent in proximity to quinoline and indole alkaloids.

AREA COVERED

In this review, the therapeutic applications of THIQ derivatives as an anticancer agent from 2016 to 2024 have been examined. The patents were gathered through comprehensive searches of the Espacenet, Google patent, WIPO, and Sci Finder databases. The therapeutic areas encompassed in the patents include numerous targets of cancer.

EXPERT OPINION

THIQ analogues play a crucial role in medicinal chemistry, with many being integral to pharmacological processes and clinical trials. Numerous THIQ compounds have been synthesized for therapeutic purposes, notably in cancer treatment. They show great promise for developing anticancer drugs, demonstrating strong affinity and efficacy against various cancer targets. The creation of multi-target ligands is a compelling avenue for THIQ-based anticancer drug discovery.

A novel and practical synthesis of CAT3: a phenanthroindolizidine alkaloid with potential in treating glioblastoma

CAT3, one of the (+)-deoxytylophorinine-based phenanthroindolizidine alkaloids, is a promising therapeutic agent for the treatment of hedgehog (Hh)-driven glioblastoma and is currently being evaluated in preclinical studies. In this paper, a novel and practical synthetic route for CAT3 was firstly demonstrated with 10% overall yield in 11 steps and has been successfully validated for pilot-plant scale preparation. Investigation of the substitution at the 3-position of phenanthrene revealed that the electron-donating functionality can well preserve the S configuration. In particular, the excellent enantiomeric excess of CAT3 (≥99% ee) was achieved by introducing the strongly electron-donating tert-butyldimethylsilyl (TBS) group.

Treatment of N,N-dibenzylamino alcohols with sulfonyl chloride leads to rearranged beta-chloro amines, precursors to beta-amino acids, and not to tetrahydroisoquinolines

[reaction: see text] Very recently, the unexpected formation of 3-substituted 1,2,3,4-tetrahydroisoquinolines starting from N,N-dibenzyl-protected beta-amino alcohols was reported. The authors claimed that treatment with tosyl chlorides induced intramolecular Friedel-Crafts alkylation. Reexamination of the reactions in our laboratory clearly proved rearranged chloro amines instead of the initially assumed tetrahydoisoquinoline structures. The chloro amines investigated can be employed as highly useful intermediates for an EPC synthesis of beta-amino nitriles and beta-amino acids.