81397-08-2

Upstream product

• 1373877-72-5 C₂₀H₁₉NO₆ 
• 99855-57-9 1,2,3,4-tetrahydro-1-hydroxymethylene-6,7-methylenedioxyisoquinoline 
• 93-07-2 Veratric acid 
• 84573-54-6 11,12-dimethoxy-2,3-methylenedioxy-berbine 
• 73609-07-1 ethyl 8-chloro-9,10-dimethoxy-2,3-methylenedioxy-13-oxonorochotensane-7-carboxylate 
• 81397-13-9 ethyl 9,10-dimethoxy-2,3-methylenedioxy-13-oxonorochotensane-7-carboxylate 
• 81397-14-0 9,10-dimethoxy-2,3-methylenedioxynorochotensan-13-one 

Relevant academic research and scientific papers

Synthesis of 8-oxoprotoberberines using acid-mediated cyclization or the Heck reaction

A facile method of synthesizing 8-oxoprotoberberines is described from 6-benzoyl-5,6,7,8-tetrahydro-[1,3]dioxolo[4,5-g]isoquinoline-5-carbaldehyde via acid-mediated cyclization or from 2-(2-iodophenethyl)isoquinolin-1(2H)-one via the Heck reaction. The present method offers several advantages, such as good yields and a simple procedure. Springer-Verlag 2011.

Chemical Transformation of Protoberberines. VI. Ring D Inversion of Protoberberine Alkaloids. Conversion of Berberine into Nonnaturally Occurring 11,12-Oxygenated Protoberberines via Spirobenzylisoquinolines

Three methods were developed for the transformation of naturally occurring 9,10-oxygenated protoberberines into non-naturally occurring 11,12-oxygenated protoberberines through ring D inversion via spirobenzylisoquinolines.Berberine (14) was converted to the spirobenzylisoquinoline (18) through regioselective cleavage of the 8,14-cycloberbine (17).Alkalinehydrolysis of the oxazolidinone (20) derived from 18 efficiently afforded the 11,12-oxygenated protoberberine (23), wich was also obtained from 8-methoxyberberinephenolbetaine (24) through treatment of the keto-hydroxy-spirobenzylisoquinoline (25) with alkali.The spirobenzylisoquinoline (26) derived from the 8,14-cycloberbine (16) was subjected to hydrogenolysis and subsequent hydrolysis to give the amino-ketone (28), photolysis of which furnished the 11,12-oxygenated protoberberine (29).Keywords - 11,12-oxygenated protoberberine; ring D inversion; retro-aldol reaction; protoberberine; spirobenzylisoquinoline; berberine; oxazolidinone ring.

RING D INVERSION OF PROTOBERBERINE ALKALOIDS. CONVERSION OF BERBERINE INTO NON-NATURALLY OCCURRING 11,12-OXYGENATED PROTOBERBERINES

Three methods were developed for the transformation of a naturally occurring 9,10-oxygenated protoberberine, berberine into a non-naturally occurring 11,12-oxygenated protoberberine through ring D inversion via a corresponding spirobenzylisoquinoline.