Towards N-alkylated phthalocyanines using 2,3,9,10,16,17,23,24-octaneopentoxyphthalocyanine

4,5-Dineopentoxyphthalonitrile was prepared from catechol and neopentyl tosylate in three steps. Condensation of this substituted phthalonitrile with lithium metal in 1-pentanol led to 2,3,9,10,16,17,23,24-octaneopentoxyphthalocyanine. Lithiation in tetrahydrofuran gave the dilithium phthalocyanine which on methylation did not give the expected N-methylated product 29,31-dimethylphthalocyanine. The precipitate formed on methylation appeared to be the N+-CH3 derivative in which one of the peripheral nitrogens was N-methylated. Methylation with 13CH3I likely yielded an N+-methylated phthalocyanine having the requisite increased mass in its mass spectrum.