A facile, practical and recyclable Cu–N–C composite catalyst with good catalytic activity for both homo- & cross-coupling of terminal alkynes.

bÃThis paper describes the synthesis of deuterium-labelled paclitaxel and its hydroxyl metabolite. Paclitaxel labelled with 2 H was obtained in four steps using the commercially available [ 2 H 5 ]benzoic chloride as the stable labelled reagent with a 40% overall yield. The hydroxyl metabolite labelled with 2 H was prepared starting from deuterium-labelled paclitaxel in six steps with a 42% overall yield based on unrecovered starting material.

A five-step synthesis of deuterium-labelled diclofenac starting from 2-phenyl[ 2 H 5 ] acetic acid is described. The synthesis prevents deuterium from scrambling during the reaction. It offers the labelled compound with over 99% isotopic enrichment. It also provides a possible alternative route for the synthesis of deuterium-labelled 4 0 -hydroxydiclofenac, which is the principal human metabolite of diclofenac.