87098-80-4

Upstream product

• 621-59-0 isovanillin 
• 55323-55-2 2-(5-(benzyloxy)-4-methoxyphenyl)-ethan-1-ol 
• 5487-33-2 O-benzylhomoisovanillic acid 
• 160857-74-9 (3-benzyloxy-4-methoxyphenyl)ketene 
• 697803-51-3 1-(3-Hydroxy-4-methoxy-benzyl)-7-methoxy-3,4-dihydro-isoquinolin-8-ol 
• 50-00-0 formaldehyd 
• 6346-05-0 3-benzyloxy-4-methoxybenzaldehyde 
• 158838-05-2 8-Benzyloxy-1-(3-benzyloxy-4-methoxy-benzyl)-7-methoxy-3,4-dihydro-isoquinoline 
• 160857-71-6 (3-benzyloxy-4-methoxyphenethylimino)triphenylphosphorane 
• 36455-21-7 3-benzyloxy-4-methoxyphenylethylamine 
• 63909-29-5 (E)-2-(benzyloxy)-1-methoxy-4-(2-nitrovinyl)benzene 

Downstream Products

• 104420-84-0 (+)-Enneaphylline 
• 87069-33-8 (+)-Sarcocapnidine 
• 81874-23-9 sarcocapnine 
• 87035-68-5 oxosarcocapnidine 

Relevant academic research and scientific papers

Total Synthesis of the Ortho-Hydroxylated Protoberberines (S)-Govaniadine, (S)-Caseamine, and (S)-Clarkeanidine via a Solvent-Directed Pictet-Spengler Reaction

The common para regioselectivity in Pictet-Spengler reactions with dopamine derivatives is redirected to the ortho position by a simple change of solvents. In combination with a chiral auxiliary on nitrogen, this ortho-selective Pictet-Spengler produced the 1-benzyltetrahydroisoquinoline alkaloids (S)-crassifoline and (S)-norcrassifoline and the bioactive 1,2-dioxygenated tetrahydroprotoberberine alkaloids (S)-govaniadine, (S)-caseamine, and (S)-clarkeanidine with high enantiopurity. Ortho/para ratios up to 89:19 and diastereomeric ratios up to 85:15 were obtained during formation of the B-ring. The general applicability of this solvent-directed regioselectivity was demonstrated with a second Pictet-Spengler reaction as required for C-ring formation of caseamine (o/p = 14:86 in trifluoroethanol) and clarkeanidine (o/p = 86:14 in toluene).

Diastereoselective Synthesis of Cularine Alkaloids via Enium Ions and an Easy Entry to Isoquinolines by Aza-Wittig Electrocyclic Ring Closure

In preliminary communications, we reported the diastereoselective synthesis of cularine and sarcocapnine via the intramolecular ring closure of nitrenium and oxenium ions, a new highly diastereoselective reductive methylation with (+)-8-phenylmenthyl chloroacetate followed by reduction with sodium borohydride, and a facile entry to the isoquinoline precursors by aza-Wittig electrocyclic ring closure. We now report the full details of the syntheses of (+)-O-demethylcularine, (+)-cularine, (+)-sarcocapnidine, (+)-sarcocapnine, and (+)-crassifoline and describe different methods of synthesis of their precursors.