Fragmentation of carbohydrate anomeric alkoxy radicals. synthesis of polyhydroxy piperidines and pyrrolidines related to carbohydrates

Imino sugars of the piperidine and pyrrolidine types can be specifically obtained when protected 5-amino-5-deoxyfuranopentoses, 5-amino-5-deoxyfuranohexoses, 6-amino-6-deoxyfuranohexoses, and 6-amino-6-deoxypyranohexoses undergo a tandem alkoxy radical beta-fragmentation-intramolecular cyclization reaction. The reaction is promoted by the system: iodosylbenzene-iodine under mild conditions. The tert-butoxycarbonyl, benzyloxycarbonyl, and diphenylphosphinoyl radicals have been studied as amino-protecting groups. Using this methodology, polyhydroxylated pyrrolidines of the D-erythrofuranoses 34 and 35, D-threofuranose 36, L-xylofuranose 42, and D-arabinofuranose 43 series and polyhydroxylated piperidines of the D-arabinopyranose type 37 and 38 were obtained.

A note on the isolation of psychrotrophic coliform organisms from faecal-polluted environments

The Simmons citrate salicin (SCS) medium was developed for the enrichment and isolation of presumptive psychrotrophic coliforms from polluted environments. The selectivity and resolution of the medium were tested with pure and mixed laboratory cultures. A procedure for the isolation of psychrotrophic coliforms from polluted environments using a lactose-bile broth and SCS medium is presented.

[Isolated ventricular inversion associated with complete atrioventricular septal defect with total anomalous pulmonary venous drainage]

Based upon the description of the clinico-pathological characteristic of a case with isolated ventricular inversion plus other cardiac malformations, the clinical, diagnostic and embryo-pathological implications of this entity are reviewed.

Seasonal variations of pollution indicators in a wildfowl reserve (Doñana National Park, Spain)

Pollution indicators in Doñana National Park show a cyclic seasonal pattern with maximum level in the autumn and minimum in the spring. While faecal streptococci proved to be the best indicator micro-organisms in this type of salty, alkaline environment, total coliforms gave an overestimation of pollution because of the presence of hydroteluric coliforms.