Efficient and chemoselective acetalization and thioacetalization of carbonyls and subsequent deprotection using InF3 as a reusable catalyst

Mg(HSO4)2/SiO2 as a Highly Efficient Catalyst for the Green Preparation of 2-Aryl-1,3-Dioxalanes/Dioxanes and Linear Acetals

“…Until now, several methods for the acetalization of the carbonyl function have been reported using ionic liquids [12][13][14][15], protonic acids such as HCl and H 2 SO 4 and Lewis acids [16][17][18][19], and transitional metal complexes including Rh, Pd, and Pt [20,21]. Some of these strategies suffer from the drawback of green chemistry, and have been associated with several shortcomings such as use of corrosive protic acids and unrecyclable catalyst, long-reaction times and low product yields, difficult work-up procedure, and the use of organic solvents.…”

Solvent-dependent regio- and stereo-selective reactions of 3-formylchromones with 2-aminobenzothiazoles and transacetalization efficiency of the product 3-((benzo[d]thiazol-2-ylimino)butyl)-4H-chromen-4-one

“…In continuation experiments for the synthesis of derivatives of compound 3 with different amines, we found that the reactions with amides (acetamide, formamide and benzamide) resulted in corresponding acetals, irrespective of the alcohol and amide used ( Table 3, Entries 1-6), with good yields (71-82%) and even in the absence of amide ( Table 3, Entry 7). These acetals are known to be formed by reactions in alcohols under both acidic 13 and basic 14,15 conditions mostly using Lewis acids as catalysts. However, their formation was unexpected when a primary amide is available as a substrate and this behaviour is contrary to its amine counter parts.…”

Chemistry and application of 4-oxo-4H-1-benzopyran-3-carboxaldehyde

“…21 Indium trifluoride catalyzed protection of the aldehyde group of ChrCHO with MeOH, PhCH 2 OH, 2,2-dimethylpropane-1,3-diol, PhSH, HSCH 2 CH 2 SH, HSCH 2 CH 2 CH 2 SH in refluxing toluene is known. 22 Acetal as well as thioacetal of ChrCHO when refluxed in MeCN-…”