反应详情

To a stirred and cooled (<10° C.) solution of 9.65 parts of 5-methoxy-2H-3,1-benzoxazine-2,4(1H)-dione in 54 parts of N,N-dimethylformamide were added portionwise 2.64 parts of a sodium hydride dispersion 50%. After stirring for 1 hour in an ice bath. 7.81 parts of iodomethane were added dropwise at <15° C. When the reaction mixture was solidified, 45 parts of N,N-dimethylformamide were added and a sodium hydride dispersion 50% was further added dropwise. Upon complete addition, stirring was continued overnight while the reaction mixture was allowed to reach room temperature. The reaction mixture was poured into ice water and 2,2'-oxybispropane was added. The precipitated product was filtered off, washed with water and dried, yielding 8.37 parts (80.7%) of 5-methoxy-1-methyl-2H-3,1-benzoxazine-2,4(1H)-dione; mp. 215.8° C. (interm. 2)

1. stirringAfter stirring for 1 hour in an ice bath
2. additionUpon complete addition
3. stirringstirring
4. customto reach room temperature
5. additionwas added
6. filtrationThe precipitated product was filtered off
7. washwashed with water
8. customdried