Modulation of chemoselectivity by protein additives. Remarkable effects in the oxidation of hyperforin
Luisella Verotta1, Erminio Lovaglio, Olov Sterner
1Dipartimento di Chimica Organica e Industriale, Via Venezian 21, 20133 Milano, Italy. luisella.verotta@unimi.it
Abstract:
Protein additives have a dramatic effect on the H(2)O(2) oxidation of hyperforin, either protecting the enolized phloroglucinol core from oxidation (human albumin) or promoting (HRP and ovalbumin) reaction pathways derived from the intermediacy of the enollactone 4, a minor component of the oxidation mixture in the absence of protein additives. To rationalize the exquisite specificity of several steps and their mechanistic oddity, an organocatalytic effect is postulated. The use of protein additives allows a straightforward and multigram preparation of the enollactone 6, an interesting multifunctionalized scaffold for bioactivity induction and/or modulation.
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