Manufacturing Process
To 1170 g ethyl acetoacetate at 100-110°C was added a little at time 1605 g
bromosuccinimide. After cooling to the mixture was added 300 ml of carbon
tetrachloride. From the mixture was isolated ethyl ester of bromoacetoacetic
acid which was distilled at 105-125°C/18 mm; yield 67%.
By condensation of the mixture 1400 g ethyl ester of bromoacetoacetic acid,
700 g bromosuccineimide, 500 ml benzene and 350 mg zinc was prepared
(R)-5,6-dihydro-4-methoxy-6-styryl-2H-pyran-2-one; melting point 157°C,
yield 60-70%.
