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Improving the Substrate Scope of the Kumada-Corriu Cross Coupling Reaction

The Ni or Pd catalysed Kumada-Corriu reaction between an aryl halide and a Grignard reagent is one of the original cross coupling reactions, and we all know that the Grignard reagent can react with suitable functional groups, such as carbonyls, on the aryl halide which limits it’s applicability.  Buchwald1 and Knochel2 have shown that by

Regioselective Chlorination of Phenols

Normally when one chlorinates a phenol one would expect to see perhaps 8:1 to 10:1 regioselectivity in favour of the para-isomer, but in this paper using N-chlorosuccinimide as the chlorinating agent, using the correct thiourea catalyst can give up to much better regioselectivity for either the o-chloro or p-chloro isomer depending on the thiourea catalysts

What does NDA Stand for?

Those of you in the pharma industry will be familiar with the acronym NDA standing for New Drug Application, but there could be a new chemical use for NDA as the sodium equivalent of LDA (lithium diisopropylamide), although the authors use NaDA, so perhaps we should use LiDA instead of LDA.  In this paper David

JUST FOR FUN…

What does 2 + 2 make? The mathematician will say 4 The chemist will say between 3.95 and 4.05 The lawyer will want to know what their fee will be for providing the information The accountant will say the answer is 4, but I’m sure you can manage with 1.6 The engineer will say the

UPDATED SOLVENT GUIDE AND SOLVENT NMR DATA

GSK were one of the first companies to publish a solvent selection guide and they have updated this gradually over the years, with the latest version of their guide being published just recently in Green Chemistry1. The new guide contains 44 more solvents taking the total number of solvents covered to 154. In addition, the

SOLVENT MAPPING

Another paper on the theme of solvents, is from Paul Murray working with the University College London and concerns the use of solvent maps and design of experiments (DoE). IN DoE solvent is usually considered to be a discrete or categorical variable, but by applying principle components analysis one can generate solvent maps so that solvent

A MORE HOLISTIC SOLVENT SELECTION TOOL

Louis Diorazio and co-workers at AstraZeneca recently published an article entitled “Toward a More Holistic Framework for Solvent Selection”, which describes the development of a solvent selection tool. Most solvent guides concentrate on Health and Environmental aspects of solvents, but where this new solvent selection tool differs is that it takes in to account issues

SOLVENT EFFECTS

At the recent ‘Scale Up of Chemical Processes Conference’ in Baveno, Italy, John Snoonian of Sunovion discussed the development and scale up of a manufacturing route to make a 5HT4 partial agonist containing a 1,2,4-oxadiazole ring. During route scouting studies on the synthesis of the benzopyrazole an interesting solvent effect was observed – see Scheme

MIYAURA BORYLATION

At the recent ‘Scale Up of Chemical Processes Conference’ in Baveno, Italy, Charles Papageorgiu of Eisai described the optimization of a borylation process to prepare boronic acid ML-826 (see Scheme 1). Scheme 1: Preparation of boronic acid ML-826 The original method using B2Pin2 and Pd(PPh3)2Cl2 as catalyst was extremely inefficient (9.25 day batch cycle time!)

PROBLEMS WITH WASTE STREAMS

At the recent ‘Scale Up of Chemical Processes Conference’ in Baveno, Italy, Wim Dermaut from Agfa presented some case studies where problems have occurred as a result of reactive chemicals present in waste streams. In the first case study a drum containing a waste stream including diethylhydroxylamine exploded. The most likely cause was caustic present