Reaction #1328422

Reaction equation

methyl 2-(2-hydroxycarbonyleth-1-yl)thio-4-chlorobenzoate

→

Methyl 5-chloro-4-oxothiochromane-8-carboxylate

Solvents

water

Conditions

Workup

1. 1
   Filtrationthe resulting precipitate was filtered off with suction
2. 2
   Otherdried

Procedure

At 70° C., 50 g (0.18 mol) of methyl 2-(2-hydroxycarbonyleth-1-yl)thio-4-chlorobenzoate were added to 500 g of polyphosphoric acid, and the mixture was stirred for a further 30 minutes. The reaction mixture was then stirred into water and the resulting precipitate was filtered off with suction and dried. This gave 41.1 g (88%) of methyl 5-chloro-4-oxothiochromane-8-carboxylate.

Source