117370-38-4

Upstream product

• 1779-49-3 Methyltriphenylphosphonium bromide 
• 149296-18-4 2-(2-Formyl-3,4,5-trimethoxy-benzyl)-malonic acid bis-(2,2,2-trichloro-ethyl) ester 
• 18833-38-0 bis(2,2,2-trichloroethyl) propanedioate 
• 3840-30-0 5-(chloromethyl)-1,2,3-trimethoxybenzene 
• 149296-17-3 2-(3,4,5-Trimethoxy-benzyl)-malonic acid bis-(2,2,2-trichloro-ethyl) ester 

Downstream Products

• 149296-01-5 Bis(2,2,2-trichloroethyl) <(5-acetoxy-4-oxo-4H-pyran-2-yl)carbonyl>-(2-ethenyl-3,4,5-trimethoxybenzyl)propanedioate 

Relevant academic research and scientific papers

Cycloadditions of 4-pyrones. An approach to colchicine

The 4-pyrone, [5-acetoxy-4-oxo-4H-pyran-2-yl]carbonyl chloride was coupled with the malonate anion of bis(2,2,2-trichloroethyl) 2-ethenyl-3,4,5-trimethoxybenzylpropanedioate and analogs thereof. These adducts then underwent intramolecular thermal cyclizations (61-100% yield) to form the two fused seven member rings of the carbon skeleton of colchicine. The malonate moiety was deprotected and decarboxylated quantitatively to provide the desired ring system which contained a bridging ether, from C7a to C11 in the C ring, and a ketone at the 7 position. Removal of the bridging ether as H2O would yield the desired tropolone. Our attempts to remove the ether bridge were unsuccessful.