C‐Phosphorylated pyrazoles. Reaction of N‐methyl‐ and N‐phenylpyrazoles with phosphorus(III) halides

Abstract

The reactions of N-methyl-and N-phenylpyrazole

Dichloro(diisopropylamino)phosphonio[5(4H)oxopyrazol‐4‐ylide‐5‐one]: Synthesis and properties

“…Previously we described the transformation of 4-phosphorylated-5-alkoxypyrazoles into ylides [3] including monohalogenoylides [4], which are now used for the synthesis of dichloroylides. It was shown that chlorination of the pyrazole-substituted diisopropylaminochlorophosphine 1 (via the dichlorophosphonium chloride 2) leads to the formation of the dichloroylide 3.…”

Facile synthesis and nematicidal activity evaluation of thiophosphinyl amide [(Pz)2P(S)NHR] and thiophosphonyl diamide [(Pz)P(S)(NHR)2] (Pz = 1,3,5-trimethylpyrazole, R = biphenyl derivatives)

“…The 1,3,5-trimethylpyrazole substituted bromophosphine (1 and 2) were prepared following a previously published protocol. 15 Due to the π-rich character of a pyrazol ring, PBr 3 can directly react with 1,3,5-trimethylpyrazole in the presence of pyridine, which acts as both a solvent and an acid acceptor, leading to the corresponding phosphorylation products 1 and 2. After a standard reaction of 1 (or 2) with the corresponding analogues of 2-aminobiphenyl, in the presence of triethylamine, the resulting crude phosphinylamine (phosphonyldiamine) directly reacted with stoichiometric amount of S 8 , giving the desired compounds 1a–1h (or 2a–2h) ( Fig.…”

“…[1][2][3][4] In the medical eld, the phosphate containing drug remdesivir has been developed, 5,6 while in the agricultural industry this approach has also garnered success, as exempli-ed by the pesticide Imicyafos. [7][8][9] It should be noted that compared with the highly investigated small molecule organophosphorus compounds (like phosphate esters), 4,[10][11][12][13] there is comparatively little research on the synthesis and bio-activity of their pyrazole derivatives, [14][15][16][17][18][19][20] an area of research that is particularly relevant since the bio-activity of such compounds is well documented. [21][22][23][24] Indeed, some of the phosphonyl pyrazole derivatives have been shown to possess biological activity, like antimicrobial, anticancer and antioxidant activities.…”

Amidine function in constructing novel types of phosphorus-containing heterocycles

“…Note that 1 is considerably more reactive towards phosphorylation than other pyrazoles. 3 This fact illustrates the strong electrondonating properties of the amidine substituent. Dichlorophosphine 2 was then transformed into bis(dialkylamino)phosphines 3a,b under mild conditions.…”