Total synthesis of Q Base (Queuine)

The total synthesis of Q Base (Queuine) has been accomplished in eleven ste ps from ribose. Mitsunobu reaction of nosyl protected amine 12 with known c yclopentenol 7, derived from ribose, gave 13, the first key intermediate in the synthesis. The pyrrolo[2,3-d]pyrimidine ring system of Q Base was buil t via a cyclocondensation reaction between a beta -aminobromoaldehyde 16, d erived from the Mitsunobu product 13, and 2,4-diamino-6-hydroxypyrimidine. Deprotection of the product from the cycloccondensation reaction (17) gave Q Base. (C) 2000 Elsevier Science Ltd. All rights reserved.