Ferrous methanesulfonate as an efficient and recyclable catalyst for chemoselective synthesis of 1,1-diacetate from aldehydes

Hexaaqua-aluminium(III) tris-(methane-sulfonate)

The title compound, [Al(H(2)O)(6)](CH(3)SO(3))(3) (common name: aluminium methane-sulfonate hexa-hydrate), was crystallized from an aqueous solution prepared by the precipitation reaction of aluminium sulfate and barium methane-sulfonate. Its crystal structure is the first of the boron group methane-sulfonates to be determined. The characteristic building block is a centrosymmetric unit containing two hexa-aqua-aluminium cations that are connected to each other by two O atoms of the -SO(3) groups in an O-H⋯O⋯H-O sequence. Further O-H⋯O hydrogen bonding links these blocks in orthogonal directions - along [010] forming a double chain array, along [10-1] forming a layered arrangement of parallel chains and along [101] forming a three-dimensional network. As indicated by the O⋯O distances of 2.600 (3)-2.715 (3) Å, the hydrogen bonds are from medium-strong to strong. A further structural feature is the arrangement of two and four methyl groups, respectively, establishing 'hydro-phobic islands' of different size, all positioned in a layer-like region perpendicular to [101]. The only other building block within this region is one of the -SO(3) groups giving a local connection between the hydro-philic structural regions on both sides of the 'hydro-phobic' one. Thermal analysis indicates that a stepwise dehydration process starts at about 413 K and proceeds via the respective penta- and dihydrate until the compound completely decomposes at about 688 K.

A convenient and efficient protocol for the synthesis of acylals catalyzed by Brønsted acidic ionic liquids under ultrasonic irradiation

The synthesis of acylals (1,1-diacetates) via the reactions of aldehydes with acetic anhydride was carried out in 85-97% yields at room temperature under ultrasound irradiation catalyzed by the Brønsted acidic ionic liquid [bmpy]HSO(4). This method provides several advantages, such as solvent-free conditions, operational simplicity, higher yields, and reduced environmental consequences. The ionic liquid was recovered and reused.