A green method for Baeyer–Villiger oxidation based on the chemo-enzymatic perhydrolysis of carboxylic acids and esters has been optimized using Novozyme-435, the immobilized form of Candida antarctica lipase B, and the complex urea–hydrogen peroxide (UHP) in ethyl acetate. This protocol previously employed for the chemo-enzymatic epoxidation of unfunctionalized olefins was shown to be effective for the Baeyer–Villiger oxidation of cyclohexanone and substituted cyclohexanones. The absence of water in the reaction media avoided any hydrolysis of the oxidized product. A minimum amount of enzyme was necessary to show the catalytic effect. The reaction yields of substituted ε-caprolactones varied depending on the nature of the substituent.

Bioassay guided fractionation of an antimycobacterial extract of Foeniculum vulgare var dulce (Apiaceae) led to the isolation and characterization of 5-hydroxyfurano-coumarin. The chemical structure of this compound was elucidated by ¹H and ¹³C (1D and 2D) Nuclear Magnetic Resonance (NMR) spectroscopy. In addition, the active fractions were analyzed by GC-MS and seventy eight compounds were identified; the major compounds were 1,3-benzenediol, 1-methoxycyclohexene, o-cymene, sorbic acid, 2-hydroxy-3-methyl-2-cyclopenten-1-one, estragole, limonene-10-ol and 3-methyl-2-cyclopenten-1-one. Twenty compounds identified in the active fractions were tested against one sensitive and three MDR strains of Mycobacterium tuberculosis using the Alamar Blue microassay. Compounds that showed some degree of antimycobacterial activity against all strains tested were the following: linoleic acid (MIC 100 µg/mL), oleic acid (MIC 100 µg/mL), 1,3-benzenediol (MIC 100–200 µg/mL), undecanal (MIC 50–200 µg/mL), and 2,4-undecadienal (MIC 25–50 µg/mL), the last being the most active compound. To our knowledge, this is the first report of the presence of 5-hydroxy-furanocoumarin in F. vulgare.