Ylides of heterocycles. VII.. I‐, N‐, P‐ and S‐ylides of pyrimidones

Abstract

Abstract The reaction of pyrimidone derivatives 1a‐d with iodosobenzene prepared in situ from diacetoxyiodobenzene or dichloroiodobenzene afforded the iodonium‐ylides 2a‐d in good yields. Their thermal rearrangement produced 5‐iodo‐4‐phenoxy‐pyrimidin‐6(1 H )‐ones 3a‐c . Reductive deiodination of 3 gave the corresponding 4‐phenoxypyrimidin‐6(1 H )‐ones 4a‐c . Acid catalized treatment of the iodonium‐ylides 2a‐d with nucleophiles such as pyridine, nicotinamide, isoquinoline, or triphenylphosphine produced the corresponding N ‐ or P ‐ylides 7, 8, 9 , and 10 , respectively. The thiophanium‐ylides 11a,c were obtained from the iodonium‐ylides 2 without the use of a catalyst. The pyridinium‐ylides 7 have been also prepared from the 5‐halopyrimidones 5 or 6 which in turn could be obtained from the reactive iodonium‐ylides 2 with hydrochloric or hydrobromic acid, respectively.