C-Stannylmethylierte N-Acetyl- und N-Formyl-aminomalonsäure-Derivate

C-Stannylmethylated N-Acetyl- and N-Formyl-aminomalonic Acid Derivatives Tin compounds of the type Me₃SnCH₂C(NHCOR) · (COOEt)₂ ( 1 : R = CH₃; 2 : R = H) are synthesized by reaction of acylaminomalonates with iodomethyl trimethylstannane. The halogenation of 1 and 2 yields the halostannylsubstituted compounds Me_3?nX_nSnCH₂C(NHCOR)(COOEt)₂ 3–6 (R = Me, H; n = 1, 2; X = Cl, Br). The decarbethoxylation (KRAPCHO reaction) of 1 and 2 gives ethyl 3 -(trimethylstannyl)-N-acyl alaninates ( 7 and 8 ). With one equivalent KOH 1 and 2 are transformed into the monoethyl malonates of the type Me₃SnCH₂C(NHCOR)(COOH)(COOEt) ( 9 : R = CH₃), which convert simultaneously under decarboxylation into 7 and 8 and by cyclisation under elimination of methane into the 1,2-oxastannolane derivatives 10 and 11 . IR, NMR data and the determination of the crystal structure reveal for MeBr₂SnCH₂C(NHCOCH₃)(COOEt)₂ ( 5 ) hexacoordinated tin by intramolecular coordination of the amide-CO and one of the ester-CO groups.