A simple and mild one-pot three-component reaction for the preparation 1,4-dihydropyridines has been developed from various aldehyde substrates, 1,3-dicarbonyl compounds (dimedone) and ammonium acetate (Hantzsch method) in the presence of a catalytic amount of phospho sulfonic acid (PSA) as an efficient and heterogeneous solid acid in EtOH at room temperature. Preparation of PSA is straightforw...

UNLABELLED Location of the sentinel lymph node in malignant melanoma and early breast cancer patients requires separate injections of radiocolloid and blue dye. These agents are administered at alternative times because of their different rates of transit. This study has elucidated why particular dyes are absorbed by the lymphatic system from an investigation of dye molecular structure as a fun...