Synthesis of15N-Labelled D-Isovaline and α-Aminoisobutyric Acid

Abstract

[15N]‐D‐isovaline was prepared from DL‐[α‐15N]‐α‐aminoisovaleramide by enzymatic resolution with Mycobacterium neoaurum. The 15N‐isotope was introduced during the Strecker synthesis of its precursor, e.g. aminoisovaleronitrile. Attempts to prepare the amino nitrile precursor of [15N]‐α‐aminoisobutyric acid (Aib) led to a poor yield and loss of the label. Significantly, improved results were obtained when a cosolvent is present during formation of aminoisobutyronitrile.

Membrane-Bound Conformation of Peptaibols with Methyl-Deuterated α-Amino Isobutyric Acids by 2H Magic Angle Spinning Solid-State NMR Spectroscopy

“…In addition, the low cost of and simplicity of synthesizing deuterated Aib represent a great advantage of the present approach. Aib may be synthesized directly by a Strecker synthesis employing acetone, ammonium chloride, and sodium cyanide as starting materials . Since the chemistry is well-established and the amino acid contains no chiral centers, the yield is generally good.…”

“…Synthesis of N -Fmoc-Aib- d 6 . The amino acid Aib (2-amino-3,3,3-trideuterio-2-trideuteriomethyl propionic acid/α-amino isobutyric acid) was synthesized as previously described . To a stirred solution of ammonium chloride (2.57 g, 48.00 mmol) and sodium cyanide (2.35 g, 48 mmol) in CH 2 Cl 2 /H 2 O 1:2 (15 mL) was added acetone- d 6 (2.94 mL, 40 mmol, 99.9% deuterated, Cambridge Isotope Laboratories).…”

Detection and Amplification of a Small Enantiomeric Imbalance in α-Amino Acids by a Helical Poly(phenylacetylene) with Crown Ether Pendants

“…( S )-Isovaline (99% purity and ee > 99%) was purchased from Acros Organics (Geel, Belgium). Racemic isovaline was prepared according to the literature procedure …”

Measuring Screw-Sense Preference in a Helical Oligomer by Comparison of 13C NMR Signal Separation at Slow and Fast Exchange

“…Labeled compounds 1 − 5 were synthesized by ligating two N 3 Aib 4 O t -Bu tetramers through a doubly 13 C-labeled Aib made by Strecker reaction of acetone- 13 C 2 (details in Supporting Information [SI]) . The location of the 13 C labels in the middle of the helix was chosen to avoid specific direct interactions with the helix termini − especially the chiral controller at the N-terminus.…”