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Development and Scale Up of a Miyauri Borylation Process Using Tetrahydroxydiboron

One of the disadvantages of Miyaura borylation is that normally a diboron ester, such as bis(pinacolato)diboron, needs to be used and the resultant coupled ester has to be hydrolysed to its corresponding acid. This leads to poor atom efficiency and longer processing times. Separating the pinacol waste from desired products can sometimes be challenging. A

Suzuki-Miyaura Coupling of Heteroaryl Halides – Understanding the trends for Pharmaceutically-Important Classes

This perspective article, from workers at Imperial College London and Pfizer, Cambridge, reviews the literature on site-selectivity in S-M coupling reactions for a wide variety of heterocycles on a case-by-case basis. It is shown that experimental parameters can critically impact the dominant catalytic species in solution and its ability to undergo the site-selectivity determining oxidative

Suzuki-Miyaura Cross-Coupling of Amides and Esters

The Suzuki-Miyaura cross coupling reaction has been widely used in industry for C-C bond formation but has not successfully been applied to unactivated substrates such as amides and esters, in which the C-N and C-O bonds are cleaved. This recent report from scientists in Wroclaw (Poland), Beijing and New Jersey gets around the normally slow

Continuous Photo-Oxidation in a Vortex reactor

Photochemistry is an attractive synthetic method but has not been used widely in industry, except for one or two special processes. In batch processes, the efficiency of light usage is poor, partly owing to the reactors becoming fouled up in the region of the lamp and continuous processes should have more favourable characteristics. There has

Green and Sustainable Solvents in Chemical Processes

The topic of green and sustainable solvents is of growing interest to industry, which recognizes the need to reduce solvent usage and to minimize the use of certain solvents of toxicological concern. This up-to-date review from the group of Hallett in the Chemical Engineering Dept at Imperial College, London has almost 500 references focusing on

Borrowing Hydrogen – a New Review

The concept of borrowing hydrogen (also known as Hydrogen auto-transfer) is a useful concept which combines transfer hydrogenation with other reactions to produce more complex molecules, exemplified by the alkylation of amines with alcohols and the reaction of benzyl alcohol with acetophenone to give 1,3 diphenylpropanone.   For the process chemist these processes seem to be

Purge Factor Calculations – in ICH Quality Guidelines

ICH M7 provides greater flexibility to assess the risk posed by Mutagenic Impurities.  This is described in section 8 – Control of the guideline and defined as a series of control options.  Of these Option 4 permits an applicant to present an argument for control based on the physico-chemical properties of a mutagen and the

New Small-Scale Photoreactor

As someone who did his PhD on photochemistry, I have always been surprised at how little photochemistry is used in making new molecules, given the unusual transformations that photochemistry can enable. However, there has been a resurgence in the use of photochemistry in the last decade in academic laboratories. But the equipment had hardly changed

Scale Up Conference Review

The Scale Up of Chemical Processes Conference, June 21st – 23rd 2017 took place in Rochester, NY. For a review of the event by sponsors Kodak Speciality Chemicals – Click HERE

Fluoride Sources for Halex Reactions

The halex reaction is a great way to introduce a fluorine atom in to an aromatic ring, but the reaction often requires high temperatures and or long reaction times if metal fluorides are used.  Tetralkylammonium fluorides are a better option due to their higher solubility in the reaction medium, however these salts are often hydrated