Synthesis of Pyrene‐4,5‐dione on a 15 g Scale

Abstract

A scalable and efficient method for the synthesis of pyrene‐4,5‐dione has been developed. The addition of N‐methylimidazole (NMI, 5 mol‐%) to a known oxidation reaction was shown to marginally improve the yield and dramatically improve the ease of the workup and thus the amount of product isolable in a day by using regular laboratory equipment.

Synthesis, Photophysical and Electronic Properties of New Red‐to‐NIR Emitting Donor–Acceptor Pyrene Derivatives

“…After removing the solvent under reduced pressure the product was obtained as a dark orange solid (7.56 g, 66 %). The spectroscopic data match those reported previously . 1 H NMR (200 MHz, CDCl 3 ): δ =8.51 (dd, J= 7 Hz, J= 1 Hz, 2 H), 8.19 (dd, J= 8 Hz, J= 1 Hz, 2 H), 7.87 (s, 2 H), 7.77 (t, J= 8 Hz, 2 H) ppm.…”

“…Bodwell and co‐workers recently introduced an improved RuO 4 ‐catalyzed oxidation procedure to obtain 1 , which is scalable and eases the workup. This method includes the additive N ‐methylimidazole, and the solvent MeCN is replaced by THF . In order to perform the Ir‐catalyzed C−H borylation, the ketone groups had to be protected as a diketal to prevent unwanted reactions with the Ir‐catalyst.…”

“…This method includes the additive N-methylimidazole, and the solvent MeCN is replaced by THF. [50] In order to perform the Ir-catalyzed CÀH borylation, [33][34][35] the ketone groups had to be protected as a diketal to prevent unwanted reactions with the Ircatalyst. The lack of reactivity of oxidized pyrene in other metal-catalyzed reactions has been reported before.…”

“…The spectroscopic data match those reported previously. [47,50,80 Pyrene-4,5-di(ethyleneglycol)ketal (2): Pyrene-4,5-dione (1) (4.92 g, 21.2 mmol, 1.00 equiv) was suspended in 200 mL of toluene and ethylene glycol (148 mL, 2.65 mol, 125 equiv) and p-toluenesulfonic acid (1.81 g, 9.53 mmol, 0.45 equiv) were added. The reaction mixture was refluxed at 125 8C for 20 h. Toluene was removed under reduced pressure and 400 mL of water.…”

Pyrene‐Fused Pyrazaacenes with Eight Rectilinearly Arranged Aromatic Rings

“…Significant progress has been made, especially in recent decades, in the development of facile and efficient methodology for the oxidation of pyrene . Even a scalable method, on a 15 g scale, was performed comfortably using standard laboratory equipment . Based on these two types of reactive intermediates, a straightforward strategy was developed to prepare pyrene‐fused pyrazazcences .…”