The compounds 1,1′-carbonylbis(3-methylpyrazole) (1), 1,1′-carbonylbis(3,5-dimethylpyrazole) (2), and 1,1′-sulfinyldipyrazole (3) have been prepared. They react with aldehydes and ketones in the presence of metal ion catalysts to form 1,1′-alkylidenedipyrazoles together with carbon dioxide, from 1 and 2, or sulfur dioxide, from 3. Tetrapyrazol-1-ylmethane results from the pyrolysis at 200° of 1,1′-carbonyldipyrazole in the presence of cobalt(II) chloride.

The metal-catalyzed reaction of 1,1′-carbonyldipyrazoles with aldehydes or ketones to give 1,1′-alkylidenedipyrazoles and carbon dioxide, the latter being derived from the amide carbonyl group as shown by labeling experiments, is sensitive to electronic and to steric substituent effects. Under comparable reaction conditions, 1,1′-carbonyldiimidazole, N-acetylpyrazole, and 1-pyrazole-N,N-diethylcarbonamide do not react with acetone while pyrazole-1-carbo(N′-phenylhydrazide) yields an anilino isocyanate dimer. These results are interpreted in terms of a mechanism that involves coordination of the metal ion at the 2,2′-nitrogen atoms of the pyrazole rings and heterolytic cleavage of an amide bond, followed by formation of a carbamate intermediate, decarboxylation, and metal ion exchange. Unsymmetrically substituted 1,1′-carbonyldipyrazoles were found to equilibrate thermally with their respective symmetrical analogs by an intermolecular exchange mechanism.

The following N-substituted azoles have been prepared: (a) diphenylphosphine derivatives of pyrazole (la), 3,5,-dimethylpyrazole (lb), 3(5)-methylpyrazole (isomers 2a and 2b), pyrrole (7), imidazole (8), and 1,2,4-triazole (9); (b) diphenylphosphinatopyrazole (46); (c) dichlorophosphinopyrazole (5a) and dichlorophosphino-3,5-dimethylpyrazole (Sb); (c) 1,l-phenylphosphinobis(pyrazo1e) (3); (d) tris (pyrazoly1) 3); ( e ) tris(pyrazoly1)phosphine (6a) et le tris(dimethy1-3,y pyrazoly1)phosphine (6b). Les methodes de synthese font appel aux reactions (i-ic): (i) l'azole avec la chlorophosphine (pour 1-3, 8, 9) ou +,P(O)Cl (4a) dans une solution Ctheree avec la triethylamine comme accepteur d'acide halogene-hydrique; (ii) la trimCthylsilylazole avec le trichlorure de phosphore (5, 6 ) ; (iii) le pyrrolidure de potassium avec la diphtnylchlorophosphine (8); (it.) l'oxydation du soufre de l a (4b). Les attributions spectrales deduites de 1'Ctude r.m.n. sont discutees.[Traduit par le journal]

. Can. J. Chem. 54, 2706Chem. 54, (1976.The syntheses of P-N bonded pyrrolyl-and 2,5-dimethylpyrrolylphosphines +,P(py),-, and +ZP(Mezpy)3-z (x = 0-2) and the oxy derivatives py3PO and (Mezpy)2P(O)Cl by the reaction of potassium pyrrolide or 2,5-dimethylpyrrolide with an appropriate chlorophosphine or with POC13 are described. Molecular structures were inferred from spectroscopic data. The P-N bonded phosphines are stable to solvolytic attack by water or alcohols and do not undergo insertion reactions with CS2, but they are oxidised by oxygen and suffer nucleophilic displacement of the azole moiety by strong base. The Lewis acid BC13 cleaves the P-N bond and CH31 reacts with only one member, +2P(py), to form a phosphonium salt. Hindered rotation about the P-N bond was detected in the (2,5-dimethylpyrroly1)phosphine series, but not among the corresponding oxy derivatives. The nature of the P-N bond and trends in the basicity of the phosphorus atom are discussed. On d k r i t les syntheses de pyrrolyl et de dimethyl-2,5 pyrrolyl phosphines +,P(P~)~-, et +,P(Me2py)3-, (x = 0-2) contenant des liens P-N et des derives oxy py3P0 et (Me2py)2P(0)C1 par la rhction du pyrrolure de potassium ou du dimethyl-2,5 pyrrolure de potassium avec une chlorophosphine approprike ou avec POC13. On a propose les structures molCculaires ii partir des donn6es spectroscopiques. Les phosphines contenant un lien P-N sont stables aux attaques solvolytiques de I'eau ou des alcools et ne subissent pas de reactions d'insertion avec le CS2; ils sont toutefois oxydees par l'oxygkne et subissent des ddplacements nuclCophiles de la portion azole sous I'influence de bases fortes. L'acide de Lewis BC13 coupe le lien P-N et le CH31 r h g i t uniquement avec le +2P(py) conduisent ii un sel de phosphonium. On a detect6 un empechement ii la rotation autours du lien P-N dans la serie dimethyl-2,5 pyrrolyl phosphine; ce n'est toutefois pas le cas dans les derives oxy correspondants. On discute de la nature du lien P-N et des tendances dans la basicit6 de I'atome de phosphore.[Traduit par le journal] Introduction The N-pyrrolylphosphines and phosphine oxides are members of the azole phosphine class of compounds, where a heteroaromatic system is bonded via nitrogen to phosphorus (1). Modifications of the chemistry of the P-N bond and of the coordination properties of the phosphorus centre, as compared to dialkylaminophosphine and tris(ary1)phosphine systems, may be expected. In this paper the syntheses and reactions of pyrrolylphosphines are described. A study of metal coordination complexes will be reported later.

. Can. J. Chem. 54, 2710Chem. 54, (1976. The new P-N bonded phosphino-and phosphinatopyrazoles 4P(Mezpz)2, (pz)3PO, (Me2pz)3-PO, +2P(S)(Mezpz), (~z )~P S , and (C2H5)2P(pz) and the arsenic derivative ( p~)~A s have been prepared and characterized (pz = pyrazolyl, Me2pz = 3,5-dimethylpyrazolyl).The reactivity of the P-N bond in phosphinopyrazoles towards electrophiles and nucleophiles is discussed. HCI, HzO, CH30H, and BC13 cleave the P-N bond, presumably via attack at the 2-N site. BF3 forms 1 :1 adducts bonded to phosphorus which are reasonably stable in the solid state. CH31 forms a phosphonium salt with diphenyl(pyrazoly1)phosphine while other members of the series do not react. All members are inert toward CS2. Nucleophiles like sodium methoxide or phenyllithium displace the pyrazolyl moiety by attack at the phosphorus. Comparisons are made with the P-N bond in dialkylaminophosphines. On discute de la rQctivitC du lien P-N des phosphinopyrazoles vis-his des Clectrophiles et des nucl~ophiles. HCI, H20, CH30H et BC13 coupent le lien P-N probablement par une attaque au niveau du 2-N. BF3 conduit des adduits 1:l lies par le phosphore qui sont assez stables h 1'Ctat solide. CH31 forme un sel de phosphonium avec la diphCnyle(pyrazoly1e)phosphine alors que les autres termes de la sCrie ne riagissent pas. Tous les termes sont inertes vis-his le CS2. Des nuclCophiles comme mCthylate de sodium et le phCnyllithium dkplacent la partie pyrazolyle par une attaque au niveau du phosphore. On fait des comparaisons avec le lien P-N des dialkylaminophosphines.[Traduit par le journal]