The metathesis reaction for side chain construction in carbocyclic sinefungin analogue synthesis

Sequential iodine-mediated diallylsilane rearrangement/asymmetric dihydroxylation: Synthesis and reactions of enantioenriched oxasilacycles

Products from an iodine-mediated diallylsilane rearrangement were taken into an asymmetric dihydroxylation (AD) reaction resulting in the formation of diastereomeric 6-membered oxasilacycles. Removal of the epimeric stereocenter among this mixture of diastereomers by elimination of iodine produced a single enantioenriched cyclic allyl silyl ether. The resulting allyl silane was then successfully engaged in several further transformations, providing an alternative means to prepare useful intermediates for enantioselective synthesis.

Enantiomeric 4'-truncated 6'-fluoro-3-deazaneplanocin and its 3-bromo derivative: Synthesis and antiviral properties, including Ebola and Marburg

In seeking to increase the library of fluorine containing adenine-derived carbocyclic nucleoside antiviral candidates, d-like and l-like 6'-fluoro-3-deazaneplanocin and its 3-bromo derivative lacking the 4'-hydroxylmethylene substituent (2/3 and 4/5, respectively) are presented. Their synthesis was accomplished from d-ribose by developing a more facile precursor route than suggested by the literature. The 2/4d-like pair displayed significant anti-filo virial properties while the enantiomeric l-like congeners 3/5 were inactive. Target compounds 2/4 also were active towards measles and norovirus. The effect of 2/4 is further evidence of the role fluoro-derived adenine carbocyclic nucleoside can play in antiviral drug discovery. Furthermore, the simplicity of their synthesis lends them to more efficacious analogs and to scale-up optimization. There were no other relevant antiviral properties for 2/3 and 4/5 (except BK polyomavirus for 3/5).

Enantiomeric 4'-Truncated 3-deaza-1',6'-isoneplanocins: Synthesis and antiviral properties including Ebola

Enantiomeric 3-deaza-1',6'-isoneplanocins (C-3 unsubstituted 7a/7b and C-3 with a bromine 8a/8b) lacking the 4'-hydroxymethyl as mechanistically designed anti-viral targets have been prepared by utilizing the Ullmann reaction. Anti-Ebola properties were found for the D-like 7a and 8a and L-like 8b. All four products showed effects against human cytomegalovirus while D-like 7a/8a affected measles; 7a was effective versus norovirus and 8a inhibited Pichinde. Both 7a and 8a produced SAHase inhibitory effects. However, the anti-EBOV activity of 7a and 8a cannot be readily correlated with this observation due with their contrasting IC₅₀ values (8a > 7a). It is to be noted that 7b showed no effects on this enzyme and 8b was minimally inhibitory. These results offer preliminary insight into the differing mechanisms of action of D- and L- like structures and enlighten structural features to guide additional antiviral agent pursuit in the isoneplanocin series.

A convergent synthesis of carbocyclic sinefungin and its C5 epimer

A convergent synthesis of carbocyclic sinefungin 2 and its C5 epimer 3 is described. The key features in our synthesis include the use of commercial available L-methionine and readily available (1R, 4S)-4-hydroxy-2-cyclopentenyl acetate as starting materials, cross-metathesis coupling, enzymatic kinetic resolution and Staudinger reduction. The current synthesis is flexible and therefore provides convenient access to the synthesis of various carbocyclic SIN analogues for biological evaluation.