Synthesis of 12-oxobenzo[c]phenanthridinones and 4-substituted 3-arylisoquinolones via Vilsmeier–Haack reaction

Synthesis of salicylaldehydes from phenols via copper-mediated duff reaction

“…The challenge to obtain ortho-selective formylation was to activate the ortho C-atom of the OH group in phenols. Since metal salts are frequently used for promoting ortho-formylation in several other methods [11][12][13][14], a few metal salts (or oxides) were selected for our investigation in the Duff reaction (Scheme 1), and Cu 2 O with oxygen came out to be the best choice for promotion of ortho-selective formylation, the ortho/para selectivity of 2.3:1 and total yield of 80 % were achieved (Table 1, entry 5). All the Cu (II) salts (Table 1, entries 3, 4 and 7), including CuSO 4 , Cu(OAc) 2 , CuO and CuCl 2 , exhibited better performance than their corresponding Cu(I) salts under anaerobic conditions, in terms of both total yields and ortho/para formylation selectivities (Table 1, entries 3, 10, 4 VS 5, and 7 VS 8).…”

“…As listed in Table 3, 1i and 1j (entries 9 and 10), which also bore a carboxyl group on the Scheme 2 Substrate scope phenolic ring, but with the carboxyl group meta-or para-to the hydroxyl group of phenol, the addition of Cu 2 O had no effect on neither selectivity nor total yields. Furthermore, for substrates bearing non-carbonyl group (Table 3, entries [11][12][13][14], addition of Cu 2 O had no impact on both selectivity and formylation yield of Duff reaction. Finally, for substrates bearing carbonyl group but no hydroxyl group, formylation by Duff reaction was not successful (Table 3, entries 15-17).…”

“…Numerous formylation methods were developed to prepare diverse aromatic aldehydes from corresponding phenols [6], such as the Duff reaction [7][8][9], Vilsmeier-Haack reaction [10][11][12], Reimer-Tiemann reaction [13][14][15], Gattermann-Koch reaction [16,17], Gattermann reaction [18,19], Rieche reaction [20][21][22], and paraformaldehyde/MgCl 2 reaction [23,24]. These methods possess their individual advantages, however, low ortho-selectivity of the most of these methods and poor yields sharply limited their application in industry [25].…”

Synthesis and Structure‐Activity Relationships of 3‐Arylisoquinolone Analogues as Highly Specific hCES2A Inhibitors

“…Compounds with the basic skeleton of isoquinolone possess broad biological activities. [8] Among them, 3-arylisoquinolones are commonly reported as the anticancer ingredients, while their inhibition against hCES have not been researched. The present study showed that compound 3 a [9] (Figure 1) could selectively inhibit hCES2A with moderate activity.…”

An efficient total synthesis of ruprechstyril fromRuprechtia tangarana

“…Several synthetic routes have been reported towards isoquinoline nucleus (Awuah & Capretta, 2010;Glushkov & Shklyaev, 2001), including the Gabriel-Colman synthesis via ring enlargement of phthalimides (Delcey et al, 1995), the Curtius rearrangement of azides derived from 2-(2-carboxyethyl)benzoic acids (Mujde, Ozcan, & Balci, 2011), condensation of amines with homophthalic anhydrides (Semple, Rydzewski, & Gardner, 1996), reaction of 2-methoxycarbonylstyrene oxide with ammonia or methylamine (Lin et al, 2003), the [4 þ 2]-cycloaddition of the ketenes to cyano ketones (Minami, Nishimoto, & Hanaoka, 1995), treatment of indanones with sodium azide (Scriven & Turnbull, 1988), solid-phase synthesis Bischler-Napieralski cyclisation (Chern & Li, 2004), palladium mediated synthesis (Khan & Masud Reza, 2005), Vilsmeier-Haack reaction of 3-arylisoquinolines (Khadka, Yang, Cho, Zhao, & Cho, 2011) and reaction of coumarin and isocoumarin derivatives with ammonia and amines. The latter method has been used in the synthesis of (�)-licoricidin (Beccalli et al, 2007), narciclasine (Khaldi et al, 1995), (þ)-deoxypancratistatin (Ohta & Kimoto, 1975) and the benzophenanthridine alkaloid nitidine (Minami et al, 1995).…”