Convenient Synthesis of Benziodazolone: New Reagents for Direct Esterification of Alcohols and Amidation of Amines

Hypervalent iodine heterocycles represent one of the important classes of hypervalent iodine reagents with many applications in organic synthesis. This paper reports a simple and convenient synthesis of benziodazolones by the reaction of readily available iodobenzamides with m-chloroperoxybenzoic acid in acetonitrile at room temperature. The structure of one of these new iodine heterocycles was confirmed by X-ray analysis. In combination with PPh3 and pyridine, these benziodazolones can smoothly react with alcohols or amines to produce the corresponding esters or amides of 3-chlorobenzoic acid, respectively. It was found that the novel benziodazolone reagent reacts more efficiently than the analogous benziodoxolone reagent in this esterification.

Biomass of a Psychrophilic Fungus as a Biocatalyst for Efficient Direct Esterification of Citronellol

A biomass-bound lipase from psychrophilic Chrysosporium pannorum A-1 is an efficient biocatalyst for direct esterification of β-citronellol and acetic acid in an organic solvent. The biomass is effectively produced by fungal submerged culture at 20 ℃, which results in lower energy consumption during the production of biocatalyst. Supplementation of the culture medium with calcium carbonate together with olive oil contributed to a significant increase in the active biomass of mycelium in one batch culture and increased the efficiency of the biocatalyst. Biomass-bound lipase showed high catalytic activity in a broad temperature range of 30–60 °C and stability up to 70 °C. A maximum molar conversion value of 98% was obtained at 30 °C in n-hexane using a 2:1 alcohol-to-acid molar ratio and 3% w/v of the biocatalyst within 24 h. The high equimolar concentration of the substrates (200 mM) did not have an adverse effect on mycelial biomass activity. Dry mycelium of C. pannorum is a promising biocatalyst for large-scale biosynthesis of citronellyl acetate, given its low-cost production, high activity at low temperatures, and reusability in a minimum of seven 24-h biocatalytic cycles.

Biocatalytic Approach for Direct Esterification of Ibuprofen with Sorbitol in Biphasic Media

Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) introduced in the 1960s and widely used as an analgesic, anti-inflammatory, and antipyretic. In its acid form, the solubility of 21 mg/L greatly limits its bioavailability. Since the bioavailability of a drug product plays a critical role in the design of oral administration dosage, this study investigated the enzymatic esterification of ibuprofen as a strategy for hydrophilization. This work proposes an enzymatic strategy for the covalent attack of highly hydrophilic molecules using acidic functions of commercially available bioactive compounds. The poorly water-soluble drug ibuprofen was esterified in a hexane/water biphasic system by direct esterification with sorbitol using the cheap biocatalyst porcine pancreas lipase (PPL), which demonstrated itself to be a suitable enzyme for the effective production of the IBU-sorbitol ester. This work reports the optimization of the esterification reaction.