Some substituted 9-phenylxanthen-9-yl protecting groups

Abstract
Xanthen-9-one 8 was converted into 9-(4-methoxyphenyl)-, 9-(4-methylphenyl)- and 9-[3(trifluoromethyl)phenyl]-xanthen-9-ol (10; R1= OMe, R2= H, 10; R1= Me, R2= H, and 10; R1= H, R2= CF3, respectively). The corresponding 5′-protected thymidine derivatives (13; R1= OMe, R2= H, 13; R1= Me, R2= H and 13; R1= H, R2= CF3) were obtained in satisfactory yields from thymidine 12 and the appropriate 9-chloro compounds (11; R1= OMe, R2= H, 11; R1= Me, R2= H and 11; R1= H, R2= CF3). In the same way, 2,7-dibromoxanthen-9-one 14 was converted into two 9-aryl-2,7-dibromoxanthen-9-ols (compounds 15a and 15b). Reaction between thymidine 12 and the corresponding 9-chlorocompounds gave the 5′-protected thymidine derivatives 16a and 16b, also in satisfactory yields. The rates of acid-catalysed cleavage of the above five 5′-protected thymidine derivatives (13; R1= OMe, R2= H, 13; R1= Me, R2= H and 13; R1= H, R2= CF3), 16a and 16b were compared with those of 5′-O-(9-phenylxanthen-9-yl)thymidine 13; R1= R2= H and 5′-O-(triphenylmethyl)thymidine 3a; B = thymin-1-yl under the same conditions.

This publication has 0 references indexed in Scilit: