Toluene

Acetone, dichloromethane (DCM), n-hexane, 2-propanol, toluene (reagent grade) were obtained from Molar Chemicals, Hungary, and they were purified by atmospheric pressure distillation. Furthermore, acetonitrile (MeCN), tetrahydrofuran (THF), methanol (MeOH), dimethyl-formamide (DMF), dimethyl-sulfoxide (DMSO), pyridine (HPLC grade, VWR, Darmstadt, Germany), ethylacetate (EtOAc), (reagent grade, Molar Chemicals, Hungary), 1,4-dioxane (reagent grade, Reanal, Hungary), 1,4-diaminonaphthalene (Sigma-Aldrich, Schnelldorf, Germany) were used without further purification. 2,6-diaminonaphthalene was purchased from Manchester Organics (London, UK) and purified by column chromatography.
The 1-amino-4-isocyanonaphthalene (1,4-ICAN) and the 2-amino-6-isocyanonaphthalene (2,6-ICAN) isomers were synthesized from the corresponding diamines (1,4- and 2,6-diaminonaphthalene), and the obtained products were characterized similarly to that reported for the 1-amino-5-isocyanonaphthalene [15 (link)]. The details of the synthesis and the characterization of 1,4-ICAN and 2,6-ICAN are given in the Supporting Information.

Succinic acid (C₄H₆O₄, SA, 99%), ethylene glycol (C₂H₆O₂, 99.99%) were purchased from Molar Chemicals Kft. (Halásztelek, Hungary). Sodium hydroxide (NaOH) and dimethyl sulfoxide (DMSO) were obtained from Merck (Gernsheim, Germany). Toluene and 1,4-dioxane were purchased from Molar Chemicals Kft. (Halásztelek, Hungary) and Sigma-Aldrich (Budapest, Hungary), respectively. All chemicals were used as received without further purification. Acetonitrile (C₂H₃N, ACN, LC-MS grade of Sigma Aldrich), Sodium hydrogen carbonate (NaHCO₃, 99+% HPLC grade of Acros Organics (Geel, Belgium)) and purified water obtained from a Millipore-MilliQ system (Sigma-Aldrich, Budapest, Hungary).