V. N. Torocheshnikov

NMR Spectra of indolizines and their σ complexes

New and previous data on the1H and13C NMR spectra of indolizines with electron-withdrawing groups at C(1), C(3), C(6), and C(8) obtained in our laboratory are reviewed. The chemical shifts in the13C NMR spectra were compared with the total atomic charge values calculated by the MNDO method. Feasibility was demonstrated for the use of PMR spectroscopy to identify isomers for pairs of 1(3)- and 6(8) -substituted indolizines and to establish the protonation site of such compounds. Evidence was obtained for the unexpected ipso protonation in 3-substituted indolizines. The spectral properties of cationic and anionic sigma complexes involving indolizines were discussed.

1-Aroyl-2-benzyl-5-hydroxypyrazolidines

The PMR spectral data show that 1-aroyl-2-benzyl-5-hydroxypyrazolidines are preferentially present in cyclic form in solution, while the proportion of the linear form increases to ∼50% in the gaseous phase, according to mass spectra.

N-acylamino derivatives of the indoline and tetrahydroquinoline series

Previously unknown N-acylamino derivatives of the indoline and tetrahydroquinoline series were synthesized. Their E,Z-isomerism was studied by NMR spectroscopy.

Synthesis and reactions of 7-?-cyanoalkylindolines

In the presence of phosphorus oxychloride N-acylaminoindolines rearrange to 7-α-cyanoalkyl(aralkyl)indolines. These have been converted to the corresponding amines, acids, and indoles.

Synthesis and structure of the ? complex of chromium with 2-phenylindolizine

The π complexing of indolizines was investigated. The first π complex of a transition metal (chromium) with a phenylindolizine ligand was synthesized. It was proved by IR, PMR, and mass spectroscopy that coordination of the metal atom is realized through the benzene ring of the molecule.