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Osmium (Os, Element 76)

Osmium, a group 8 d-block transition metal discovered in 1803 by the English chemist Smithson Tennant, is the rarest of the stable elements. Concentrations in the Earth’s crust are around 50 parts per trillion. The metal is found in nature uncombinrd or alloyed with its neighbour, iridium, in the alloys iridosmine or osmiridium. Around 500Kg

Intermolecular reductive C-N cross coupling of nitroarenes and boronic acids by P(III) / P(V)=O catalysis

When approaching the synthesis of an aryl- or heteroaryl- amine most people would turn to a suitable transition metal (Pd, Cu or Ni) catalysed C-N cross-coupling reaction- most likely a Buchwald-Hartwig reaction, or, if this has limited success, Ullmann or Chan-Evans-Lam couplings.1 Photoredox approaches using aryloxy amides as a source of amidyl radicals began a trend

Some Good News from the UK (let’s not mention Brexit)

At last some good news from the UK, we are delighted to hear that the Pfizer Sandwich UK site is recruiting!  They are seeking new colleagues to join their Chemical R&D department in a number of areas to support their rapidly growing global portfolio.  These roles have been created to assist acceleration of early Active

Xenon- the light at the end of the tunnel

Xenon (Xe, Element 54) Xenon, from the Greek for ‘stranger’ is a colourless, odourless group 18 noble gas. Discovered in 1898 in London by William Ramsay, xenon is produced commercially by the fractional distillation of liquid air and is isolated as a by-product of the cryogenic production of oxygen and nitrogen. The concentration in the

The Balz-Schiemann Reaction

Aryl- and heteroaryl- diazonium tetrafluoroborate salts, prepared by diazotization of an aniline in the presence of HBF4, are unique in that in many cases they are sufficiently stable to isolate. Thermal decomposition of these salts at elevated temperatures results in fluoro-dediazoniation and formation of the corresponding aryl or heteroaryl fluoride- the Balz-Schiemann reaction.1a,bRadiolabelled 18F compounds

Selective N-methylation of amides using (chloromethyl)dimethylchlorosilane/ fluoride: Application to the large scale synthesis of a pyrimidone intermediate for Raltegravir

Raltegravir (free base) Selective N- v’s O- alkylation of an amide can be challenging and somewhat unpredictable- the outcome being highly dependent on the structure of the substrate. A good example of this is the N-methylated pyrimidone intermediate (5) en route to Merck’s antiretroviral drug Raltegravir.1 Direct methylation of amide (4) (Figure 1) using MeI gives significant

What is the simplest marketed therapeutic?

Lithium (Li, Element 3) Lithium, first member of the group 1 alkali metals, was discovered in 1817 by Johan August Arfwedson. It’s been around since the dawn of (astronomical) time- both stable isotopes, Li6 and Li7, being among a small handful of elements created in the Big Bang.1Terrestrially its highly abundant in seawater (up to

All about the base- or lack of it! Base-free nickel catalysed decarbonylative Suzuki-Miyaura coupling of acid fluorides

Figure 1: Suzuki-Miyaura Coupling   It’s a reaction that most organic chemists have run at some stage in their careers and is almost certainly in the running for the most widely used C-C bond forming reaction. First reported in 1979, the Suzuki-Miyaura cross-coupling between an organoboron nucleophile and an aryl halide electrophile is still ubiquitous in

Which metallic element, central to the activity of the marine algal enzyme bromoperoxidase, is slowly converting 120 billion tons of bromide ions into organobromine compounds in the world’s oceans ?

Vanadium (V, Element 23) Vanadium, a group 5 transition metal, discovered in 1801 by Andres Manuel del Rio, occurs naturally as a component of vanadinite (Pb5(VO4)3Cl), one of the main industrial ores used as a source of the metal. Over 60 ores are known, with 70-80 thousand tonnes of ore mined globally each year, producing

Heterocyclic phosphonium salts- powerful intermediates for pyridine coupling

Heterocyclic phosphonium salts- powerful intermediates for pyridine coupling:- I’ve always had a keen interest in phosphorus chemistry and have followed the work of the McNally group at Colorado state on heterocyclic phosphonium salts closely. In late 2016 a paper describing synthesis and application of the so called HetPhos salts for C4 (or C2) functionalisation of