REDUCTION OF TRANS-CINNAMALDEHYDE BY HYDROGENATION OVER RANEY-NICKEL MEDIATED BY DERIVATIVES OF BETA-CYCLODEXTRIN

The extent and rates of reduction of both olefinic double bond and the aldehyde functions have been found to be altered in the reduction of cinnamaldehyde over Raney nickel. The formation of 3-phenylpropanol is found to be faster in the presence of BCD than the control and is slo wer in the case of DMBCD and BCD-polymer mediated reactions than the c ontrol. The reactions mediated by BCD, BCD-polymer and DMBCD have been found to maintain a certain proportion of equilibrium concentration o f 3-phenylpropanal, i.e. 18-29%, 34-37% and 45-48% respectively for so metime after which complete conversion to 3-phenylpropanol is effected . The reduction of double bond is found to be faster than that of the aldehydic function in all the four cases. UV, H-1 and C-13 NMR spectro scopic studies of both BCD and DMBCD complexes indicate more than one mode of disposition for cinnamaldehyde inside the cyclodextrin cavity. Although the phenyl ring is found to be embedded inside the cavity in both the cases, alpha, beta-unsaturated aldehydic function is found t o be partially exposed. In the case of DMBCD a 1:2 (DMBCD: cinnamaldeh yde) complex is detected and in the case of BCD, a 1:1 complex is dete cted with binding constant values of 17370 +/- 1000 M(-1) and 27390 +/ - 2600 M(-1), respectively.