- Efficient and suitable preparation of N-sulfonyl-1,2,3,4- tetrahydroisoquinolines and ring analogues using recyclable H6P 2W18O62·24H2O/SiO 2 catalyst
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Silica gel-supported H6P2W18O 62·24H2O is an efficient and recyclable catalyst for the synthesis of biologically important molecules. Several substituted N-sulfonyl-1,2,3,4-tetrahydroisoquinolines and ring analogues can be prepared in very good yields and purity by direct reaction of N-aralkylsulfonamides and sym-trioxane by a Pictet-Spengler reaction in the presence of a catalytic amount of silica gel-supported H6P2W18O 62·24H2O. Reactions were performed in a low volume of toluene, at 70 °C and for a short time, typically 15 to 30 min. The title heterocyclic compounds were prepared in very good yields (60%-95%) using the described procedure results in a clean and useful alternative, which has the advantages of a greener methodology with operative simplicity, use of a reusable and non-corrosive solid catalyst, soft reaction conditions, low reaction times, and good yields.
- Pasquale, Gustavo,Ruiz, Diego,Autino, Juan,Baronetti, Graciela,Thomas, Horacio,Romanelli, Gustavo
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p. 758 - 763
(2012/10/29)
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- Synthesis of Fused Heterocycles: 1,2,3,4-Tetrahydroisoquinolines and Ring Homologues via Sulphonamidomethylation
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The title heterocycles (3) have been obtained by a two-step synthesis; namely an initial intramolecular sulphonamidomethylation of N-aralkylsulphonamides (1) in acid media followed by desulphonylation of compounds (2) under moderate conditions, either by reduction or acid hydrolysis.Generally both steps gave good or high yields of compounds (3) variously substituted in the aromatic ring and with a six-, seven-, or eight-membered heterocyclic ring.
- Orazi, Orfeo O.,Corral, Renee A.,Giaccio, Hector
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p. 1977 - 1982
(2007/10/02)
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