Graham Richard Geen

Green chemistry measures for process research and development

A set of metrics has been developed which enables a simple assessment to be made of batch processes in terms of waste, energy usage, and chemistry efficiency. It is intended to raise awareness of green chemistry by providing a tool to assist chemists in monitoring progress in the reduction of environmental impact as they design new routes and modify processes.

A versatile synthesis of fully aromatic benzo[c]phenanthridine alkaloids

Abstract A versatile new approach for the synthesis of benzo[ c ]phenanthridine alkaloids is described and is illustrated by the preparation of eight different alkaloids. The key steps are Smiles rearrangements, which allow easy access to 2-bromo-1-naphthylamines from 2-bromo-1-naphthols, and the attachment of the D-ring unit by Suzuki coupling.

A New Route to Famciclovir via Palladium Catalysed Allylation

Abstract An efficient route to the acyclic nucleoside analogue famciclovir has been developed based on a palladium(0) catalysed coupling of 2-amino-6-chloropurine and an allylic carbonate sidechain derived from 2,2-dimethyl-1,3-dioxan-5-one. The reaction proceeds via a highly N-9 regioselective purine allylation step involving a novel palladium mediated N-7 to N-9 rearrangement.

A Direct and High Yielding Route to 2-(5-Tetrazolyl) Substituted Benzopyran-4-ones: Synthesis of Pranlukast

Abstract A direct and high yielding route to 2-(5-tetrazolyl)benzopyran-4-ones 1, including pranlukast 1a is described. This involves the Claisen condensation reaction between the relevant hydroxyacetophenone 2 and the ethyl ester of tetrazole-2-carboxylic acid 5 to give the 1,3-diketone 6, which is then cyclised to give the desired benzopyran-4-ones 1.