4, R= CI nucleoside series that structurally can be considered a ring-contracted analogue of pseudouridine or an analogue of the sulfhydryl reagent N-ethylmaleimide (7). Although 1 and 7 inhibit cellular growth in a similar manner, the former is not simply an indiscriminate alkylating agent as is the latter: nucleosides prevent the inhibitory effects of showdomycin but not those of N-eth~ lmaleimide.~ Apparently, the ribose moiety of 1 contributes to a ...
![[3,4-diacetyloxy-5-(2,5-dioxopyrrol-1-yl)oxolan-2-yl]methyl acetate Structure](https://image.chemsrc.com/caspic/382/53209-76-0.png)