Synthesis of dipeptide isosteres by cross-metathesis

ADMET Polymerization of Amino‐Acid‐Based Diene

“…The amino‐acid‐based diene monomers were prepared by N ‐alkylation of 2,5‐diketopiperazine, also referred to as piper­azine‐2,5‐dione or glycine anhydride, with allyl bromide ( 1a ) or 4‐bromo‐1‐butene ( 1b ), as outlined in Scheme …”

“…The amino-acid-based diene monomers were prepared by N -alkylation of 2,5-diketopiperazine, also referred to as piperazine-2,5-dione or glycine anhydride, with allyl bromide ( 1a ) or 4-bromo-1-butene ( 1b ), as outlined in Scheme 1 . [ 12 ] The two dienes were isolated in moderate to low yields (56% and 37%, respectively), which could be attributed to the rather poor solubility of the glycine anhydride starting material in aprotic organic solvents. The alternate route of dimerization of non-biological unsaturated amino acid derivatives appeared not feasible for reasons of low solubility and availability (only allylglycine and homoallylglycine are available from commercial source).…”

“…1 H NMR (400 MHz, CDCl 3 ): δ /ppm = 5.76 (ddt, J = 17.1, 10.2, 6.9, 2H), 5.12 (d, J = 17.1 Hz, 2H), 5.09 (d, J = 10.2 Hz, 2H), 3.95 (s, 4H), 3.47 (t, J = 7.1 Hz, 4H), 2.33 (q, J = 7.0 Hz, 4H). Melting point: 98 °C (Lit . 98–99 °C).…”

“…The obtained solid was further purifi ed via column chromatography over silica gel with acetone/heptanes 1:1 v/v yielding 2.18 g of colorless solid (56%). 1 [ 12 ] 98-99 °C).…”

Visible light-induced selective hydrobromodifluoromethylation of alkenes with dibromodifluoromethane

“…13 C NMR was recorded on 400 MHz spectrometer. Substrates 1iq 25 and 1w 26 were prepared according to literature procedures. The following abbreviations were used to explain the multiplicities: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet.…”