A new synthesis of pyrrolo[1,2-c]quinazoline from quinazolinium N-ylides: a re-investigation

Abstract

The structure of the products obtained when generating quinazolinium-3-methylides in the absence of an activated alkyne has been investigated using X-ray diffraction and NOE experiments in high resolution NMR. All data are in agreement with a pyrrolo[1,2-c]quinazoline structure having aromatic and benzoyl substituents in positions 2 and 3 respectively, and a hydrogen in position 1, in contrast to previous assignments with hydrogen in position 3.

Copper-Catalyzed Synthesis of Pyrrolo[1,2-c]quinazolines and Pyrrolo[2,1-a]isoquinolines and Antiplasmodial Evaluation

“…Melting points were determined using a Buchi M-560 basic melting point apparatus. 1 H, 13 C, and 19 F NMR spectra were recorded on a Bruker DRX 400 MHz spectrometer. Chemical shifts (δ) were presented in parts per million units and the coupling constants (J) in Hertz (Hz).…”

“…1 H NMR (400 MHz, CDCl 3 ): δ 8.65 (s, 1H), 7.95 (dd, J = 7.7, 1.6 Hz, 1H), 7.81 (dd, J = 7.7, 1.6 Hz, 1H), 7.48 (pd, J = 7.3, 1.6 Hz, 2H), 7.35 (dd, J = 5.1, 1.0 Hz, 1H), 7.22 (dd, J = 3.6, 1.0 Hz, 1H), 7.14 (dd, J = 5.1, 3.6 Hz, 1H), 7.05 (s, 1H), 2.74 (s, 3H). 13 HRMS (ESI) m/z: calcd for C 18 H 13 BrN 2 [(M + H)] + , 337.0340; found, 337.0339.…”

“…1 H NMR (400 MHz, CDCl 3 ): δ 8.60 (s, 1H), 7.78 (dd, J = 8.7, 5.4 Hz, 1H), 7.56 (dd, J = 9.0, 1.8 Hz, 1H), 7.53−7.44 (m, 4H), 7.36 (t, J = 6.8 Hz, 1H), 7.14 (td, J = 8.7, 1.9 Hz, 1H), 6.98 (s, 1H), 2.67 (s, 3H). 13 C{ 1 H} NMR (100 MHz, CDCl 3 ): δ 161.8 (J = 247.1 Hz), 135.6, 135.3, 133.9, 130.3 (J = 9.28 Hz), 129.1, 128.9, 128.4, 127.5, 127.0, 122.7 (J = 10.5 Hz), 119.0, 115.2 (J = 23.9 Hz), 106.9 (J = 24.06 Hz), 101.5, 10.2. 19 F{ 1 H} NMR (377 MHz, CDCl 3 ): δ −112.15.…”

“…1 H NMR (400 MHz, CDCl 3 ): δ 8.71 (s, 1H), 7.54�partially overlapping signals (d, J = 7.9 Hz, 1H), 7.51�partially overlapping signals (d, J = 7.8 Hz, 2H), 7.47 (d, J = 7.5 Hz, 2H), 7.45− 7.40 (m, 1H), 7.34 (t, J = 7.0 Hz, 1H), 7.00 (s, 1H), 6.92 (d, J = 7.9 Hz, 1H), 4.06 (s, 3H), 2.67 (s, 3H). 13 C{ 1 H} NMR (100 MHz, CDCl 3 ): δ 154.9, 135.4, 128.9, 128.7, 128.4, 127.9, 127.0, 126. c]quinazoline (3t).…”

“…Usually, pyrroloquinazoline derivatives are synthesized through cyclization of functionalized pyrroles . Moreover, there are few reports in the literature describing the synthesis of pyrroloquinazolines starting from quinazolines . Due to their relevant biological activities, the search for environmentally more benign methods for the synthesis of these scaffolds has attracted attention in recent years …”