Related Experiment Video
Updated: Aug 9, 2026

Quantification of Fungal Colonization, Sporogenesis, and Production of Mycotoxins Using Kernel Bioassays
Published on: April 23, 2012
Steroid hydroxylations with Botryodiplodia malorum and Colletotrichum lini
Andrea Romano1, Diego Romano, Enzio Ragg
1Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy.
Abstract:
An improved procedure for the microbial hydroxylations of dehydroepiandrosterone (DHEA, 1) and 15 beta,16 beta-methylene-dehydroepiandrosterone (2) was studied using whole cells of Botryodiplodia malorum and Colletotrichum lini. C. lini catalyzed 7 alpha- and 15 alpha-hydroxylation of 1 and 7 alpha-hydroxylation of 2, while B. malorum gave 7 beta-hydroxylation of both the substrates. The stability of the enzymatic activity was higher in the presence of co-substrates (i.e., glucose or mannitol) allowing for repeated batches of the biotransformations. The yields of 7 alpha,15 alpha-dihydroxy-1 production were improved obtaining 5.8 gl(-1) (recovered product) from 7.0 gl(-1) of substrate. The structures of the hydroxylated products were assigned by a combination of two-dimensional NMR proton-proton and proton-carbon correlation techniques.
Related Concept Videos
Preparation of Diols and Pinacol Rearrangement
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
Antifungal Agents
Hydroboration-Oxidation of Alkenes
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
