M. Pilar Ruiz

Organocatalyzed three-component Ugi and Passerini reactions of 4-oxoazetidine-2-carbaldehydes and azetidine-2,3-diones. Application to the synthesis of γ-lactams and γ-lactones.

The organocatalyzed U-3CR of 4-oxoazetidine-2-carbaldehydes has been studied. In addition, the organocatalyzed P-3CR of 4-oxoazetidine-2-carbaldehydes and azetidine-2,3-diones has been described for the first time. U-3CR and P-3CR adducts have been obtained in good yields and reasonable diastereoselectivities. Phenyl phosphinic acid has been the catalyst of choice to study the scope of both organocatalyzed multicomponent reactions using a variety of β-lactams, isocyanides, and amines. Highly functionalized U-3CR and P-3CR adducts derived from β-lactams have proved to be useful substrates for the preparation of enantiopure γ-lactams and γ-lactones via N1-C2 β-lactam ring opening/cyclization under acidic or basic conditions.

Rhodium-Catalyzed Synthesis of 3-Hydroxy-β-lactams via Oxonium Ylide Generation: Three-Component Reaction between Azetidine-2,3-diones, Ethyl Diazoacetate, and Alcohols

3-Substituted-3-hydroxy-beta-lactams, with two new adjacent stereogenic centers, have been prepared in a single step by a rhodium-catalyzed, three-component reaction between azetidine-2,3-diones, ethyl diazoacetate, and alcohols. Good to moderate stereoselectivity was obtained depending on the alcohol used. The stereochemistry of the new centers has been undoubtedly assigned by single crystal X-ray diffraction.

Gut load and transit time in Hormogaster elisae (Oligochaeta, Hormogastridae) in laboratory cultures

Abstract The gut load and gut transit time (GTT) of the endogeic earthworm Hormogaster elisae in laboratory cultures at 18xa0°C and 23xa0oC were studied. The GTT, 5.25xa0hxa0±xa00.40 at 18xa0oC and 3.63xa0hxa0±xa00.46 at 23xa0oC, was determined by staining the soil with alimentary colouring (tartrazine). The gut load was calculated with two methods: earthworm mass difference, before and after voiding the gut, and dry mass of the gut content. The gut load ranged between 168 and 261xa0mg wet mass g live earthworm mass –1 (mass difference method) or 137–196xa0mg dry mass g live earthworm mass –1 (dry mass method). With the obtained data a potential annual soil turnover for H.xa0elisae was calculated: 211–470xa0kg wet soil mass kg live earthworm mass –1 year –1 (mass difference method) or 176–325xa0kg dry soil mass kg live earthworm mass –1 year –1 (dry mass method).