RESUMO
We report herein the development of two pathways for the preparation of levo-praziquantel (R-PZQ), which involves three-/four-step processes of a mechanochemical (asymmetric) aza-Henry/acylation reaction, a hydrogenation reaction, (chiral resolution) and a solvent-free acylation-ring closing reaction. The key intermediate (R)-1-aminomethyl tetrahydroisoquinoline could be obtained either by chiral resolution with a rational reuse of the S-isomer or by mechanochemical enantioselective synthesis that refrained from using a bulky toxic solvent. The efficiency and scalability of both the developed routes were demonstrated and desired target product was obtained in a satisfactory yield with excellent enantiopurity (>99%), offering practical, concise and environmentally friendly alternatives to access R-PZQ.
RESUMO
More than 55 million individuals are suffering from Alzheimer's disease (AD), while the effective therapeutic strategies remain elusive. Our previous study identified a lysosome-enhancing lead compound LH2-051 with a tetrahydroisoquinoline scaffold through a novel dopamine transporter-cyclin-dependent kinase 9-transcription factor EB (DAT-CDK9-TFEB) regulation mechanism to promote TFEB activation and lysosome biogenesis. Here, we launched a comprehensive structure-activity relationship study for LH2-051, and 47 new derivatives were designed and synthesized, in which several compounds exhibited remarkable lysosome-enhancing activities. Notably, compounds 37 and 45 exhibited more favorable TFEB activation and lysosome biogenesis capabilities, good safety profiles, and excellent pharmacokinetic profiles with high brain penetration. Further investigations demonstrated that both compounds significantly enhance the clearance of Aß aggregates and ameliorate the impairment of learning, memory, and cognition in APP/PS1 mice. Overall, these results indicated that compounds 37 and 45 are promising preclinical drug candidates for the treatment of AD.