Novel and mild route to phthalocyanines and 3-iminoisoindolin-1-ones via N,N-diethylhydroxylamine-promoted conversion of phthalonitriles and a dramatic solvent-dependence of the reaction

Refluxing a mixture of phthalonitrile (C6RRRR4)-R-1-R-2-R-3(CN)(2) 1 (R-1-R-4 =H), or its substituted derivatives 2 (R-1, R-3, R-4 = H, R-2 = Me), or 3 (R-1, R-4 =H, R-2, R-3=Cl) (1equiv.) and N,N-diethylhydroxylamine, Et2NOH, (4equivs.) in methanol for 4 h results (Route A) in precipitation of the symmetrical (6 and 8) and an isomeric mixture of unsymmetrical (7) phthalocyanines, isolated in good (55-65 %) yields. The reaction of phthalonitriles 1, 2, or 4 (R-1, R-3, R-4 =H, R-2 =NO2) (4equivs.) with Et2NOH (8 equivs.) in the presence of a metal salt MCl2 (M = Zn, Cd, Co, Ni) (1 equiv.) in n-BuOH or without solvent results in the formation of metallated phthalocyanine species (9-17). Upon refluxing in freshly dis- tilled dry chloroform, phthalonitrile I or its substituted analogues 2, 3 or 5 (R-1-R-4= F) (1 equiv.) react with NN-diethylhydroxylamine (2 equivs.) affording 3-iminoisoindolin- 1 -ones 18-21 (Route B) isolated in good yields (55-80 %). All the prepared compounds were characterized with C, H, and N elemental analyses, ESI-MS, IR, and compounds 18-21 also by ID (H-1, C-13{H-1}), and 2D (H-1, (15) N-HMBC and H-1,C-13-HMQC,H-1,C-13-HMBC) NMR spectroscopy.