INFLUENCE OF EMBEDDED PHENOL GROUPS INSIDE BETA-CYCLODEXTRIN CAVITY IN SELECTIVE METHYLATION OF 2,4-DIHYDROXYBENZALDEHYDE

Although the yields of 2-hydroxy-4-methoxybenzaldehyde (2) formed with one equivalent of BCD and control are comparable, the proportions of compound 2 formed with 0.2 equivalents of heptakis-2,6-di-o-methyl-bet a-cyclodextrin (DMBCD) and 0.5 equivalents of water-insoluble BCD-poly mer (BCD-polymer) are definitely higher (80.9% and 90.3% respectively) . It is observed that while the extent of conversion of 2,4-dihydroxyb enzaldehyde increases, the proportions of 2,4-dimethoxybenzaldehyde fo rmed decreases when BCD and its derivatives are used. The observed sel ectivities have been discussed in terms of specific orientation of 2,4 -dihydroxybeenzaldehyde inside beta-cyclodextrin cavity.