3-Triazine derivatives l a and l b react with phosphorus (111) reagents, to give regioselectively phosphorylated products at C-3 or N-2 depending on the nature of the substituent at C-3 and the phosphorus reagent used. 3-chlorotriazine la reacts with cyclic phosphites Za, b, and acyclic phosphites 3a-c to give the phosphonate products 6 and 10, respectively. On the other hand, reaction of la with 2c leads to the formation of its 3-dimethylamino-derivative 8. Reaction of la with triphenylphosphine gave the phosphonium salt 11. Solvolysis of 11 with aqueous methanol gave 3-hydroxytriazine l b and triphenylphosphine. Treatment of 3-hydroxy-triazine l b with 2-chloro-l.3,2-dioxaphospholane 2d results in formation of phosphoramidite 12 at the N-2.?

1,3-Diphenyl-2-(hydroxyimino)-1,3-propanedione 1 reacted with phosphonium ylides 2a,b to give mainly the substituted 1-hydroxy-2,3-dihydropyrroles 6a,b along with the novel ylides 10a,b whereas the phosphono substituted-N-heterocycles 11a,b and 14a,b were obtained from the reaction of 1 with a-phosphoryl carbanion counterparts 3a,b. Reaction of 1 with cyanomethylene(triphenyl)phosphorane 2c afforded the Wittig product 17 and the oxazole derivative 18 while the phosphono 2,2-disubstituted dihydrooxazole 20 and the diolefin 19 were produced in the reaction with the phosphonate ylide 3c. Application of the unsaturated carbanions 2d and 3d on 1 yielded the pyrrole 23 and the phosphono substituted 2H-1,4-oxazine 25, respectively.The Wittig reaction of compounds other than aldehydes and ketones, 1-3 for example anhydrides, imides and amides as well as a-imino carbonyl compounds, has been extensively studied and in many cases provides a useful method for the preparation of heterocyclic molecules. In contrast, the analogous Wittig-Horner (Horner-Wadswarth-Emmons, HWE) reaction has received a little attention 1c,4 although the reaction of some o-quinonimines with saturated phosphoryl carbanions giving unexpected products has been studied by Boulos and coworkers. 4As part of our continuing study on the application of Wittig synthons on a-imino carbonyl compounds (oximes 5 and hydrazones 6 ) for the synthesis of N-heterocycles, we report in this paper a comparative study on the behavior of 1,3-diphenyl-2-(hydroxyimino)-1,3-propanedione 1 toward alkylidenephosphoranes 2, relative to their phosphonate counterparts 3 (Figure 1). The investigation was undertaken in the hope of formation of N-heterocycles and the relevant phosphonate derivatives.The required oxime 1 was prepared according to the literature. 7 Treatment 8 of 1 with ethoxycarbonylmethylene(triphenyl)phosphorane 2a (2 molar amounts) in boiling chloroform gave diethyl 5-benzoyl-4-phenyl-1-hydroxy-2,3-dihydropyrrole-2,3-dicarboxylate 6a as the major product (48%) along with the novel ylide 10a in 18% yield. Scheme 1 Figure 1Downloaded by: University of Arizona Library. Copyrighted material.

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The heterocycle-substituted 1,1-bisphosphonates 3a,b, 7, 10a,b and 12a,b were synthesized from the parent alkylidene substrates 2a,b, 6, 8a,b and 11a,b and methylenebisphosphonate 1 by a Michael addition reaction in different yields. Hydrolysis of 1,1bisphosphonate product 3a with concentrated hydrochloric acid produced the corresponding 1,1-bisphosphonic acid 13.

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