Environmentally Friendly Preparation of Amidoalkyl Naphthols

Zirconocene dichloride catalyzed multi-component synthesis of 1-amidoalkyl-2-naphthols at ambient temperature

“…To further expand the scope of the present method, the replacement of aryl aldehydes with heterocyclic and aliphatic aldehydes was examined. To our delight, furfuraldehyde, thiophene-2-aldehyde (Table 3, entries f and g) as well as formaldehyde (Table 3, entry h) reacted, giving satisfactory [32] 186 (182-184) [27] -------- [32] 187 (182-183) [48] 191 (190)(191)(192)(193) [53] [56] 223 (222-223) [ product yields. The molecular structure of products 4a2z were elucidated from their IR and 1 H and 13 C NMR spectra, as described for 4p.…”

“…The 1 H NMR spectra of 4p exhibited two sharp singlet signals at d 1.92 and 2.23 ppm, readily recognized as a methyl group, as well as broad singlets at 8.31 and 9.89 ppm, indicating N-H and O-H, respectively. Eleven signals in the aromatic region gave rise to characteristic peaks for an [53] 228 (228-230) [ [48] 233 (234-236) [ …”

Silica Supported Methanesulfonic Acid as an Efficient and Reusable Heterogeneous Catalyst for the Synthesis of Amidoalkyl Naphthols

“…The most important thing was that aliphatic aldehydes also underwent the transformation conveniently (Table 2, Entries 10, 11 and 22), whereas the reactions of aliphatic aldehydes in most reported literatures were sluggish and no desired products were isolated. 5,6,10,11,13,16 Besides benzamide, acetamide and urea were studied in the amidoalkylation reaction, which showed the reactive activity was benzamide＞acetamide＞urea.…”

“…Moreover, some of them encountered difficulties in preparing amidoalkyl naphthols from aliphatic aldehydes. 5,6,10,11,13,16 Therefore, the discovery of new, inexpensive and mild catalyst that might overcome these drawbacks for the synthesis of amidoalkyl naphthols is highly desirable.…”

Facile One-Pot Synthesis of 1-Amidoalkyl-2-Naphthols by RuCl2(PPh3)3-Catalyzed Multi-Component Reactions

“…Although numerous methods for the synthesis of 1-amidoalkyl-2-naphthols have been reported, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] there is still demand for simpler, less toxic, more effective, and milder catalysts. Our interest in developing a mild and efficient synthetic method that provides a variety of 1-amidoalkyl-2-naphthols has led us to looking into more convenient and safely usable catalysts.…”