REACTION OF ARSENIC TRIHALIDES WITH NUCLEOSIDES . HALOMETHYLENE DIMETHYLAMMONIUM HALIDE . A NEW HALOGENATING AGENT FOR NUCLEOSIDES

The reaction of 2′,3′-O-isopropylideneuridine (1) and uridine (6) with arsenic trichloride and arsenic tribromide gave good yields of 5′-deoxy-5′-chloro(bromo)-2′,3′-O-isopropylideneuridine (3a and b) and 5′-deoxy-5′-chloro-(bromo)uridine (7a and b) when carried out in N,N-dimethylformamide (DMF). Arsenic triiodide gave poor results. Specificity for the 5′ position was found in the case of uridine. Two new nucleoside halogenating agents, chloromethylenedimethylammonium chloride (2a) and bromomethylenedimethylammonium bromide (2b), were found to be the actual halogenating agents. These agents gave excellent halogenation at the 5′ position of both 1 and 6. Comparison was made of the facility by which these chloro and bromo derivatives cyclized to 5′-O2-cyclo nucleosides 4 and 8. Attempts at the synthesis of nucleoside 5′-arsenate 5 indicated that these compounds may be too unstable to be isolated. © 1969, American Chemical Society. All rights reserved.