A. John Blacker

Iridium-catalysed amine alkylation with alcohols in water

Amines have been directly alkylated with alcohols using 1 mol% [Cp*IrI(2)](2) catalyst in water in the absence of base or other additives.

Platinum-Catalysed Allylic Alkylation: Reactivity, Enantioselectivity, and Regioselectivity

The use of platinum complexes as catalysts for allylic substitution has been studied. A variety of different complexes catalyse the reaction, and several substrates have been tested. In the alkylation of mono(alkyl)-substituted allylic acetates, regioselectivity is highly dependent on ligand choice. By using tricyclohexylphosphine as the ligand, almost complete formation of branched products is observed. The development of a highly enantioselective (ca. 80-90% ee) reaction that makes use of chiral diphenylphosphinooxazoline ligands (abbreviated as (S)-PN) is also described. The enantioselectivity is highly dependent on the ratio of ligand to platinum (when the ratio ligand/Pt is greater than 1:1, the ee drops off dramatically). This is in contrast to palladium and is interpreted in terms of differing coordination chemistry for the two metals ((S)-PN is hemilabile when complexed to platinum) and should be of significance to future systems that utilise heterobidentate ligands. The crystal structures of two isoelectronic platinum and palladium complexes [[(S)-PN]MCl2] are also described.

Online quantitative mass spectrometry for the rapid adaptive optimisation of automated flow reactors

An automated continuous reactor for the synthesis of organic compounds, which uses online mass spectrometry (MS) for reaction monitoring and product quantification, is presented. Quantitative and rapid MS monitoring was developed and calibrated using HPLC. The amidation of methyl nicotinate with aqueous MeNH2 was optimised using design of experiments and a self-optimisation algorithm approach to produce >93% yield.

Stereoselective dioxygenase-catalysed benzylic hydroxylation at prochiral methylene groups in the chemoenzymatic synthesis of enantiopure vicinal aminoindanols

Abstract Enantiopure benzylic alcohols containing two stereogenic centres in a cis -relationship result from stereoselective monohydroxylation of achiral 2-substituted indans in cultures of Pseudomonas putida UV4 and are used in the chemoenzymatic synthesis of both cis - and trans -aminoindanol enantiomers.

Self-optimisation of the final stage in the synthesis of EGFR kinase inhibitor AZD9291 using an automated flow reactor

Self-optimising flow reactors combine online analysis with evolutionary feedback algorithms to rapidly achieve optimum conditions. This technique has been applied to the final bond-forming step in the synthesis of AZD9291, an irreversible epidermal growth factor receptor kinase inhibitor developed by AstraZeneca. A four parameter optimisation of a telescoped amide coupling followed by an elimination reaction was achieved using at-line high performance liquid chromatography. Optimisations were initially carried out on a model compound (2,4-dimethoxyaniline) and the data used to track the formation of various impurities and ultimately propose a mechanism for their formation. Our protocol could then be applied to the optimisation of the 2-step telescoped reaction to synthesise AZD9291 in 89% yield.

Lipophilic modification of oligonucleotides

Abstract Methods for attaching lipophilic side-chains to an amino-modified uracil base in oligonucleotides via orthogonal amide and disulphide linkages are described. The oligonucleotide conjugates are characterised in terms of their distinctive chromatographic and spectroscopic properties.

ELECTROPHILIC AMINATION OF CATECHOLBORONATE ESTERS FORMED IN THE ASYMMETRIC HYDROBORATION OF VINYLARENES

Abstract (S)-(4-Methoxyphenyl)-ethyl-1,3,2-benzodioxaborole, (S)-1-(4-chlorophenyl)ethyl-1,3,2-benzodioxaborole and (S)-1-indanyl-1,3,2-benzodioxaborole, intermediates in the catalytic asymmetric hydroboration of 4-chloro- and 4-methoxystyrene, were isolated as pure oils in 75%, 84% and 49% yield respectively. For the first example, amination with N-chloromagnesio-N-methyl-O-trimethylsilylhydroxylamine gave a mixture of (S)-1-(4-methoxyphenyl)-N-methylethylamine in 33% yield, 88% e.e. and (S)-1-(4-methoxyphenyl) ethanol in 31% yield, 86% e.e.. Related results were obtained in the other cases, and the steps of catalytic hydroboration and amination could be combined in a single sequence without isolation of the intermediate. Numerous variants were carried out in the amination procedure with only marginal improvements in chemoselectivity. An investigation of the mechanism was carried out using low temperature heteronuclear NMR on 13C-1-(S)-1-(4-chlorophenyl)ethyl-1,3,2-benzodioxaborole. The dual pathway is a result of an irreversible and unselective initial step.

A mild hydration of nitriles catalysed by copper(ii) acetate.

A simple, mild and general procedure for the hydration of nitriles to amides using copper as catalyst and promoted by N,N-diethylhydroxylamine is described. The reaction can be conducted in water at low temperature in short reaction times. This new procedure allows amides to be obtained from a wide range of substrates in excellent yields.

Multiple molecular recognition and catalysis. Nucleotide binding and ATP hydrolysis by a receptor molecule bearing an anion binding site, an intercalator group, and a catalytic site

The polytopic receptor molecule (1), containing a macrocyclic polyamine as anion receptor subunit and an acridine group for stacking interaction, strongly binds nucleotides in aqueous solution by multiple site binding and catalyses ATP hydrolysis with increased selectivity.

Covalent modification in aqueous solution of poly‐γ‐D‐glutamic acid from bacillus licheniformis

Methods for the covalent modification in aqueous solution of poly-γ-D-glutamic acid from Bacillus licheniformis have been studied. Co-derivatization of a synthetic UV-absorbent amine and ethanolamine, using a water-soluble carbodi-imide coupling agent, yielded a water-soluble modified polymer. Derivatization of the polymer was accompanied by cleavage of the γ-linked polypeptide backbone, and a reduction in molecular mass from 170 to 10 kDa. A procedure was developed for the removal of noncovalently bound ligands by treatment with 5 M CaCl2. The polymer sidechains also reacted in aqueous solution with p-nitrophenyl acetate to form covalent linkages.