Yv. Tomilov et al., Different reactivities of regioisomeric azimines, adducts of phthalimidonitrene with 5-bromospiro[1-pyrazoline-3,1 '-cyclopropane], RUSS CHEM B, 49(11), 2000, pp. 1919-1922
The addition of the phthalimidonitrene fragment. resulting from oxidation o
f N-aminophthalimide by lead tetraacetate at -20 to -30 degreesC, to the N=
N-bond of 5-bromospiro[1-pyrazoline-3,1'-cyclopropane] (1) affords, apart f
rom the stable 5-bromoN-(spiro[1-pyrazolinio-3,1-cyclopropane])-N-phthalimi
doamide (azimine 2), regioisomeric azimine 3, which is completely transform
ed into 3-acetoxy-N-(spiro[1-pyrazolinio-5,1'-cyclopropane])- N-phthalimido
amide (4) under the reaction conditions. The acetoxy group in this product
easily. undergoes nucleophilic substitution on treatment with MeOH. NaN3. o
r the starting bromopyrazoline 1. The structures of azimines obtained were
established using N M R spectra. and the structure of the product of reacti
on of 4 with 1 was additionally proved by X-ray difraction data.