55375-91-2

Upstream product

• 55375-97-8 N-(1,2,3,4-tetrahydro-1-isoquinolinylmethyl)benzamide 
• 79-04-9 chloroacetyl chloride 
• 55375-94-5 1-(benzoylamino-methyl)-2-chloroacetyl-1,2,3,4-tetrahydro-isoquinoline 
• 98-88-4 benzoyl chloride 
• 495-69-2 Hippuric Acid 
• 17376-04-4 2-phenethyl iodide 
• 87693-78-5 4-benzoyl-2,6-dioxo-1-phenethyl piperazine 
• 90142-12-4 C₂₁H₂₆N₂O₄ 
• 59795-89-0 phenethyl isocyanide 
• 65-85-0 benzoic acid 
• 55268-74-1 2-cyclohexanecarbonyl-1,2,3,6,7,11b-hexahydro-pyrazino[2,1-a]isoquinolin-4-one 
• 61196-37-0 2,3,6,7-tetrahydro-1H-pyrazino[2,1-a]isoquinolin-4(11bH)-one 
• 100-52-7 benzaldehyde 
• 87693-76-3 4-benzoylpiperazine-2,6-dione 

Downstream Products

• 55268-74-1 2-cyclohexanecarbonyl-1,2,3,6,7,11b-hexahydro-pyrazino[2,1-a]isoquinolin-4-one 
• 105279-85-4 2-benzyl-1,2,3,6,7,11b-hexahydro-4H-pyrazino<2,1-a>isoquinolin-4-one 
• 61196-37-0 2,3,6,7-tetrahydro-1H-pyrazino[2,1-a]isoquinolin-4(11bH)-one 

Relevant academic research and scientific papers

Combining Incompatible Processes for Deracemization of a Praziquantel Derivative under Flow Conditions

An efficient deracemization method for conversion of the racemate to the desirable (R)-enantiomer of Praziquantel has been developed by coupling incompatible racemization and crystallization processes. By a library approach, a derivative that crystallizes as a conglomerate has been identified. Racemization occurs via reversible hydrogenation over a palladium on carbon (Pd/C) packed column at 130 °C, whereas deracemization is achieved by alternating crystal growth/dissolution steps with temperature cycling between 5–15 °C. These incompatible processes are combined by means of a flow system resulting in complete deracemization of the solid phase to the desired (R)-enantiomer (98 % ee). Such an unprecedented deracemization by a decoupled crystallization/racemization approach can readily be turned into a practical process and opens new opportunities for the development of essential enantiomerically pure building blocks that require harsh methods for racemization.

Synthesis and SAR studies of praziquantel derivatives with activity against Schistosoma japonicum

The synthesis and structure-activity relationship (SAR) studies of praziquantel derivatives with activity against adult Schistosoma japonicum are described. Several of them showed better worm killing activity than praziquantel and could serve as leads for further optimization.

MCR Synthesis of Praziquantel Derivatives

Schistosomiasis, a high volume neglected tropical disease affecting more than 200 million people worldwide, can only be effectively treated by the tetrahydroisoquinoline drug praziquantel (PZQ). Herein, we describe an efficient approach to access PZQ derivatives by the Ugi 4-component reaction followed by the Pictet-Spengler reaction in a two-step, one-pot procedure. 30 novel PZQ derivatives are described based on the Ugi 4-component reaction and an X-ray structure of a novel derivative revealing different conformation compared with PZQ is discussed. Several analogues comparable in activity to the drug PZQ have been identified based on an in vitro Schistosoma mansoni worm viability assay.

A NEW SYNTHESIS 2-ACYL-1,2,3,6,7,11b-HEXAHYDROPYRAZINOISOQUINOLIN-4-ONES BASED ON N-CYANOMETHYL DERIVATIVES OF 2-PHENYL-ETHYLAMIDES OF ACYLGLYCINES

A new route for the synthesis of 2-acyl-1,2,3,6,7,11b-hexahydropyrazinoisoquinolin-4-ones has been studied which includes a stage in which substituted piperazinones are obtained by reductive cyclization of N-cyanomethyl derivatives of 2-phenylethylamides of acylglycines under influence of Raney alloy in formic acid.

USE OF INTERPHASE CATALYSIS IN THE SYNTHESIS OF 2-ACYL-4-OXOPYRAZINOISOQUINOLINES AND 4-ACYL-2-PIPERAZINONES

2-acetyl-4-oxopyrazinoisoquinolines and 4-acyl-2-piperazinones have been synthesized, with interphase catalysis, by the intramolecular N-alkylation of the corresponding diamides.

4-Acyl-2,6-dioxo-1-phenethyl piperozines

2-Acyl-1,3,4,6,7,11b-hexahydro-2H-pyrazino-[2,1-a]-4-isoquinoleinones having anthelmintic activity of the formula STR1 are prepared from 4-acyl-2,6-dioxopierazines by reaction with a phenethyl halide, selective reduction of one of the oxo groups and cyclization, by the novel intermediates of formula STR2 in which Y represents O or H, OH.

Process for the production of (±)-4-oxo-1,2,3,6,7,11b-hexahydro-4H-pyrazino[2,1-a]isoquinoline derivatives

This invention discloses a process for the preparation of (±)-4-oxo-1,2,3,6,7,11b-hexahydro-4H-pyrazino[2,1-a]isoquinoline derivatives which comprises conducting an intramolecular cyclization reaction of the compounds of formulas II III in an acid medium. STR1

NEW SYNTHESES OF PRAZIQUANTEL : 2-(CYCLOHEXYLCARBONYL)-1,2,3,6,7,11b-HEXAHYDRO-4H-PYRAZINOISOQUINOLIN-4-ONE

This paper describes two different synthetic pathways for praziquantel, a new broad spectrum schistosomicide and cestocide.Easy to apply on an industrial scale, they involve a selective reduction of 4-acyl-1-phenethylpiperazine-2,6-dione in 4-acyl-6-hydroxy-1-phenethylpiperazin-2-one, the cyclisation of wchich in acetic medium gives tricyclic compounds 2-acyl-1,2,3,6,7,11b-hexahydro-4H-pyrazinisoquinolin-4-one.