Synthesis of 2-organylselenopheno[2,3-b]pyridines and 1,6-diazaselenanthrenes via radical cascade reactions using tert-butyl nitrite

Abstract

We describe herein an alternative method to prepare 2-organylselenopheno [2,3-b]pyridines starting from bis(3-amino-2-pyridyl) diselenide and aryl-and alkylacetylenes in the presence of t BuONO in CH3NO2 as solvent. The reactions were conducted at 80 °C for 2 hours, and six selenopheno[2,3-b]pyridine derivatives were obtained in satisfactory yields, ranging from 10% to 41%. Using the same conditions, but in the absence of the alkyne counterpart, three new 1,6-diazaselenanthrenes were obtained with yields ranging from 41% to 47%. These compounds are unknown in the literature.

Recent Advances in the Synthesis of Selenophenes and Their Derivatives

“…However, the reaction may also go through another pathway, which consists in a nucleophilic attack (SNAr) of the selenium anion to the 2-chloroalkylpyridine 150, followed by an intramolecular hydroselenation reaction of the triple bond (Path II) (Scheme 103). In addition, some of us [182] Thus, when the reaction was performed using arylacetylenes with electron-donating groups at the para-position of the aromatic ring, the respective fused selenophenes 151b-d were obtained in similar yields than that using the neutral phenylacetylene (151a). In contrast, the presence of the electron-withdrawing Cl-substituent at the aromatic ring caused a fast consumption of the starting material; however, the product 151e was obtained in only 10% yield, due to the formation of After some control experiments, the authors were able to propose a mechanism for the synthesis of 2-organylselenopheno[2,3-b]pyridines 151.…”

Synthesis of 2‐Organylchalcogenopheno[2,3‐b]pyridines from Elemental Chalcogen and NaBH4/PEG‐400 as a Reducing System: Antioxidant and Antinociceptive Properties

“…The product 3 was isolated by column chromatography using hexane/ethyl acetate (97 : 3) as eluent. [52] Yield: 0.050 g (77 %); slightly yellowish solid, m.p. : 86-88°C.…”

“…: 91-92°C. 1 Pentylselenopheno[2,3-b]pyridine (3 m): [52] Yield: 0.038 g (60 %); orange oil. 1 H NMR (CDCl 3 , 400 MHz) δ = 8.39 (dd, J = 4.7 and 1.6 Hz, 1H); 7.83 (dd, J = 7.9 and 1.6 Hz, 1H); 7.22 (dd, J = 7.9 and 4.7 Hz, 1H); 7.05 (t, J = 1.1 Hz, 1H); 2.94 (dt, J = 7.3 and 1.1 Hz, 2H); 1.75 (quint, J = 7.3 Hz, 2H); 1.41-1.35 (m, 4H); 0.91 (t, J = 7.3 Hz, 3H).…”

“…Recently, our research group described a method to prepare 2-organylselenopheno [2,3-b]pyridines starting from bis(3-amino-2-pyridyl) diselenide and aryl-or alkylacetylenes in the presence of t BuONO as a nitrosating agent. [52] This method was used to synthesize selenopheno [2,3-b]pyridine derivatives (Scheme 1C).…”

“…Tolyl)selenopheno[2,3-b]pyridine (3 d):[52] Yield: 0.053 g (77 %); yellow solid, m.p. : 108-109°C 1.…”