Synthesis of Optically Active 2‐Amino‐1,3,4‐oxadiazoles and their Hybrid Peptides

Rapid access to reverse-turn peptidomimetics by a three-component Ugi reaction of 3,4-dihydroisoquinoline

“…Experimental 1 H and 13 C NMR spectra were recorded on a Bruker Avance 400 spectrometer (400 and 100 MHz, respectively). Chemical shifts are expressed in ppm relative to TMS for 1 H NMR spectra and relative to CDCl 3 (77.16 ppm) or DMSO-d 6 (39.51 ppm) signal for 13 C NMR spectra.…”

“…Experimental 1 H and 13 C NMR spectra were recorded on a Bruker Avance 400 spectrometer (400 and 100 MHz, respectively). Chemical shifts are expressed in ppm relative to TMS for 1 H NMR spectra and relative to CDCl 3 (77.16 ppm) or DMSO-d 6 (39.51 ppm) signal for 13 C NMR spectra. Some 13 C NMR spectra have been recorded using the APT pulse sequence; the signals of CH and CH 3 are positive while those of CH 2 and quaternary carbons are negative.…”

“…s, NH); 3.50 (2H, t, J = 7.0, CH 2 ); 2.81 (2H, t, J =7.0, CH 2 ). 13 C NMR spectrum (CDCl 3 ), δ, ppm: 161.4; 138.6; 128.8; 128.7; 126.6; 39.2; 35.5. Crude 2-phenylethylamine (7.0 g, 0.47 mol) and polyphosphoric acid (20 ml) were heated at 160°C overnight.…”

“…s, NH); 5.94 (1H, s, CH); 4.48-4.32 (2H, m, CH 2 Ph); 3.81 (1H, ddd, J = 12.8, J = 8.2, J = 4.7) and 3.74-3.64 (1H, m, CH 2 ); 3.06 (1H, dt, J = 15.8, J = 4.7) and 2.95-2.85 (1H, m, CH 2 ); 2.18 (3H, s, CH 3 ). 13 Ethyl (2-acetyl-1,2,3,4-tetrahydroisoquinolin-1-ylcarbonyl)glycinate (1b). 1 H NMR spectrum (CDCl 3 ), δ, ppm (J, Hz): 7.43 (1H, br.…”

“…Heterocyclic scaffolds have been extensively used to this goal. 12,13 The exploitation of constrained peptidomimetics in medicinal chemistry is often limited by the fact that long and inefficient synthetic sequences are often required. With this regards, multicomponent reactions [14][15][16][17][18] can be very effective in the synthesis of complex and highly functionalized scaffolds in few steps and often in high yields.…”