Synthesis of Isotopically Labelled L-Phenylalanine and L-Tyrosine

Pentiptycene Chemistry: New Pentiptycene Building Blocks Derived from Pentiptycene Quinones

“…16 In addition, the bromo group in 19 can be replaced by a cyano group (i.e., 23), which can be in turn reduced to a formyl group (i.e., 24) (Scheme 7) according to the known procedures. 17,18 These results should ensure 18 and 19 as useful building blocks for the synthesis of more complicated pentiptycene derivatives.…”

Phenylalanine meta‐Hydroxylase: A Single Residue Mediates Mechanistic Control of Aromatic Amino Acid Hydroxylation

“…In this work, substrate deuterium labelling was employed to probe the mechanism of Phe3H . [3,5‐D 2 ]‐ l ‐Phe was synthesised in six steps from toluidine by enzymatic conversion of [3,5‐D 2 ]phenylpyruvate to [3,5‐D 2 ]‐ l ‐phenylalanine as the final step . The final l ‐phenylalanine consisted of 90 % D 2 , 10 % D 1 and <1 % D 0 l ‐Phe as determined by integration of residual 5‐H signal in the 1 H NMR spectrum and the relative intensities of isotope peaks in the mass spectrum.…”

Novel Synthesis of Naturally Occurring Pulvinones: A Heck Coupling, Transesterification­, and Dieckmann Condensation Strategy

“…The inefficiency of the acylation of benzylmagnesium 13 halides by bis(trifluoroethyl) oxalate (as opposed to dialkyl oxalates 14 ) and the scarcity of related acylations by activated monoalkyl oxalates 15 were the origin of our quest. Using aromatic aldehydes 12 as an arene source suggested several threestep and two-step approaches, but none is entirely without drawbacks: Condensation with in situ formed azlactone in the presence of sodium acetate 16 or with hydantoin/sodium acetate 17 gives the corresponding benzylideneoxazolones 10 16 and benzylidenehydantoins 11, 17 respectively. Hydrolysis 16,17 followed by esterification 16 furnishes hydroxycinnamates 13 after a total of three steps.…”

“…Using aromatic aldehydes 12 as an arene source suggested several threestep and two-step approaches, but none is entirely without drawbacks: Condensation with in situ formed azlactone in the presence of sodium acetate 16 or with hydantoin/sodium acetate 17 gives the corresponding benzylideneoxazolones 10 16 and benzylidenehydantoins 11, 17 respectively. Hydrolysis 16,17 followed by esterification 16 furnishes hydroxycinnamates 13 after a total of three steps. A two-step conversion of arenecarbaldehydes 12 into hydroxycinnamates 13 consists of a Darzen glycidic ester synthesis to give 14 and a semi-pinacol rearrangement.…”