Enantiospecific synthesis of (+)-ribasine

Photocycloaddition of Phthalimide Anion to Alkenes − A Highly Efficient, Convergent Method for [2]Benzazepine Synthesis

“…IR (neat): ν ˜ϭ 3187, 1658, 1597 cm Ϫ1 . 1 H NMR (CDCl 3 ): δ ϭ 7.97 (dd, J ϭ 2.0, 6.6 Hz, 1 H, 6-H), 7.75Ϫ7.12 (m, 8 H, Ar-H), 4.18 (dd, J ϭ 4.1, 9.9 Hz, 1 H, 4-H), 3.85 (ddd, J ϭ 6.0, 9.9, 15.0 Hz, 1 H, 3ax-H), 3.65 (ddd, J ϭ 6.0, 4.1, 15.0 Hz, 1 H, 3eq-H) ppm. 13 With α-Methylstyrene (34 mmol, 1 h): Unchanged phthalimide (90 mg, 9%), 13 (668 mg, 41%).…”

“…IR (KBr): ν ˜ϭ 3205, 1683, 1669 cm Ϫ1 . 1 H NMR (CDCl 3 ): δ ϭ 7.88 (dd, J ϭ 7.4, 2.0 Hz, 1 H, 6-H), 7.73 (br. t, 1 H, NH), 7.63 (dt, J ϭ 7.4, 2.0 Hz, 1 H, 7-H), 7.56 (dt, J ϭ 7.4, 2.0 Hz, 1 H, 8-H), 7.45 (dd, J ϭ 7.4, 2.0 Hz, 1 H, 9-H), 7.36Ϫ7.17 (m, 5 H, Ar-H), 3.89 (dd, J ϭ 16.0, 6.0 Hz, 1 H, 3-H), 3.48 (dd, J ϭ 16.0, 6.0 Hz, 1 H, 3-H), 1.70 (s, 3 H, CH 3 ) ppm.…”

“…The [2]benzazepine skeleton is a common structural feature found in a variety of naturally occurring and synthetic bioactive compounds. Examples are found in the ribasinetype alkaloids, which possess an indanobenzazepine structure, [1] and the galanthamine class of Amarillidaceae alkaloids, which have a spiro-linked benzazepine structure. [2] Galanthamine, the parent compound in the latter family, and its synthetic analogues are cholinesterase inhibitors and are currently undergoing testing in Alzheimer's disease therapy.…”

Single‐Biocatalyst Synthesis of Enantiopure d‐Arylalanines Exploiting an Engineered d‐Amino Acid Dehydrogenase

“…The d ‐enantiomers of natural and non‐proteinogenic amino acids are not only key moieties in complex natural products but also increasingly relevant as building blocks in modern synthetic and pharmaceutical chemistry. Aromatic d ‐amino acids, such as d ‐phenylalanine and other d ‐arylalanines, are of particular importance (Figure ) as they are incorporated in natural products such as antibacterial peptides (e.g., fungisporin, polymyxin, gramicidin) and alkaloids (e.g., ribasine), as well as in pharmaceutical ingredients, such as antidiabetics (e.g., nateglinide), anticoagulants (e.g., PPACK), anti‐inflammatory formyl peptide receptor 1 antagonists, cyclic plasmin inhibitors for the treatment of perioperative bleeding, and melanocortin 4 receptor agonists for the treatment of obesity . One particularly noteworthy example is cetrorelix, an unnatural decapeptide containing five d ‐amino acids (three of which are d ‐phenylalanine derivatives), used for the treatment of hormone‐sensitive cancers.…”

Iridium‐Catalyzed Asymmetric Hydrogenation of N‐Alkyl α‐Aryl Furan‐Containing Imines: an Efficient Route to Unnatural N‐Alkyl Arylalanines and Related Derivatives.

“…[4] In recent years, D-arylalanines have attracted the attention of organic and medicinal chemists because of their presence in natural products as well as their potential use as building blocks in the design and optimization of bioactive peptides and peptidomimetics. [5,6] N-Alkylation of amino acids, highlighted by Nmethylation, has become a powerful method to modulate the properties of acyclic and macrocyclic peptides, including proteolytic stability, conformational stability, selectivity and cellular permeability (Figure 1). [7] In addition, the introduction of N-alkylated residues into synthetic peptides changes the hydrogen bond patterns giving access to new conformational designs.…”