SYNTHESES AND REACTIONS OF SOME CYCLOPROPYL-SUBSTITUTED IMINES - PART1

Quenching the reaction solution from cyclopropanecarbonitrile and cycl opropylmagnesium bromide in tetrahydrofuran (THF) with anhydrous NH3 g ave an about equimolar mixture of dicyclopropyl ketimine (3) and 1,1-d icyclopropane-carboximidoylcyclopropane (4). Reactions of the ketimine s 3 and 4 with some nucleophiles are described. Thus, reaction of 4 wi th malononitrile gave a good yield of no-5-(3,3-dicyanopropyl)-4,6-dic yclopropylpyridine (6). Neat 4, catalysed by MgCl2, gave a self-conden sation product, riazadispiro{bicyclo[3.3.1]nona-2,6-diene-4,1':8,1 ''- dicyclopropane} (7), while an equimolar mixture of neat 3 and 4 with c atalytic amounts of MgCl2 gave a mixed condensation product, 2',2',4', 6',-tetracyclopropylspiro[cyclopropyl-1 ,5'-(1',5'-dihydropyrimidine)] (8). Hydrolysis of 4 at medium pH gave a mixture of 7 and the partly hydrolysed 4: necarbonyl-1-cyclopropanecarboximidoylcyclopropane (10). Reaction of 3 with cyclopropylamine gave N-cyclopropyldicyclopropyl k etimine (11). Gas phase FTIR-spectra of 4 and 10 indicated intramolecu lar hydrogen bonds. The structures of 7 and 8 were established by sing le-crystal X-ray analyses. In the bicyclic compound 7 the apical nitro gen atom is pyramidal, making the structure asymmetric (both enantiome rs present in the unit cell), as confirmed by solid-state C-13 NMR spe ctroscopy. On the other hand solution C-13 NMR shows a high degree of symmetry, explainable by rapid inversion at the apical nitrogen atom.