Preparation of the enantiomeric forms of 9-(5-deoxy-.alpha.-threo-pent-4-enofuranosyl)adenine and 9-(3,5-dideoxy-.beta.-D-glycero-pent-4-enofuranosyl)adenine and in vitro antileukemic screening

The preparation and use of 5-deoxy-5-iodo-1,2-O-isopropylidene-alpha-D-xylofuranose and 5-deoxy-5-iodo-1,2-O-isopropylidene-alpha-D-arabinofuranose in the synthesis of the L and D forms of 9-(5-deoxy-alpha-threo-pent-4-enofuranosyl)adenine, respectively, are described. The preparation of 9-(3,5-dideoxy-beta-D-glycero-pent-4-enofuranosyl)adenine (19) was accomplished from either 3,5-dideoxy-5-iodo-1,2-O-isopropylidene-alpha-D-erythro-pentofuranose or 3,5-dideoxy-5-iodo-1,2-O-isopropylidene-beta-L-threo-pentofuranose. In each case, acetolysis was performed to obtain the acetates which were condensed with 6-(benzamidochloromercuri)purine by the titanium tetrachloride method. Treatment with 1,5-diazabicyclo[5.4.0]undec-5-ene and removal of the blocking groups produced the desired nucleosides. Only 19 showed inhibitory activity toward leukemia L1210 in vitro.