A Novel Type of Spironucleosides: 2′,5′-O-Bis-TBDMS Uridine-3′-spiro-3′ ′-isoxazolidin-5′′-one and Its Thymidine Congener.

Abstract TSAO analogues, 2′,5′-O-bis-TBDMS uridine-3′-spiro-3′-isoxazolidin-5′-one (9) and its thymidine congener 10, as well as model spiro sugar derivatives (3 and 4) have been prepared from the corresponding nitrones through a stereospecific tandem nucleophilic attack. Compounds 9 and 10 which are bioisosters of TSAO-U and T respectively but which lack an amino group on the spiro ring, were found inactive against both HIV-1 and HIV-2. +This paper is dedicated to Prof. Y. Mizuno on the occasion of his 75th birthday.