Synthesen,chemische Reaktionen und NMR-spektroskopische Untersuchungen substituierter Phosphonopyruvate

Phosphonopyruvates: Syntheses, NMR Investigations, and Reactions The new 3-(diethoxyphosphoryl)-2-oxopropanoates 5–24 and -propanamides 25–38 with various substituents at C(3) were prepared in moderate-to-good yields (Schemes 2 and 3, Tables 1 and 2). It was shown that they adopt a preferred conformation in which the diethoxyphosphoryl group and the substituent at C(4) are antiperiplanar to each other (see B ). The keto-enol tautomerization of phosphonopyruvates with Ph? C(3) (see 20 ) and MeS? C(3) (see 24 and 33 ) was examined. In CHCl₃, two tautomeric species exist, whereas in dimetylsulfoxide (DMSO), three tautomeric forms are observed. Oxime ethers, an oxime, and a phenylhydrazone of unsubstituted phosphonopyruvates were prepared (see 40–44 ), and quinoxalin-2(1H)-ones could be obtained from the reaction of pyruvates with 4,5-dimethylbenzene-1,2-diamine (see 45–47 ).