Chlorination of 2-substituted 1-hydroxyindoles

Optimization of pyrrolo[3,4‐f]indole‐5,7‐dione and indole‐5,6‐dicarbonitrile derivatives as inhibitors of monoamine oxidase

“…New synthetic approaches for the synthesis of 3‐chloro‐, 3‐bromoindole‐5,6‐dicarbonitriles, 3‐chloro‐, 3‐bromopyrrolo[3,4‐ f ]indole‐5,7‐diones, and the corresponding 1‐hydroxy derivatives (Chirkova, ; Chirkova & Filimonov, ) have been developed and are reported in literature (Chirkova et al, ; Chirkova, Kabanova, et al, ; Chirkova, Kabanova, Filimonov, Abramov, et al, ; Chirkova, Kabanova, Filimonov, Samet, et al, ). These syntheses are based on the chlorination or bromination of 2‐aryl‐1‐hydroxyindole‐5,6‐dicarbonitriles ( 13 ) or corresponding pyrrolo[3,4‐ f ]indole‐5,7‐diones ( 16 ) with N ‐chloro‐, N ‐bromosuccinimide (Schemes ).…”

“…Single crystal X‐ray diffraction data were collected with a SMART APEX2 CCD diffractometer ( λ (Mo‐Kα) = 0.71073 å, graphite monochromator, ω ‐scans) at 120 K. The syntheses of compounds 4a – d and 5a – d were performed as previously described (Chirkova, Kabanova, et al, ). Compounds 7a – b , 8a – b , and 15 were synthesized according the literature protocol (Chirkova, Chernov, et al, ), while 9i – l and 10a – d were synthesized as described previously (Chirkova, Kabanova, Filimonov, Samet, et al, ). Compounds 13 (Filimonov et al, ), 14 (Chirkova et al, ), 16 , 9m (Chirkova et al, ), and 17 (Chirkova, Kabanova, Filimonov, Abramov, et al, ) were synthesized as described previously.…”

“…Compounds 7a-b, 8a-b, and 15 were synthesized according the literature protocol (Chirkova, Chernov, et al, 2017), while 9i-l and 10a-d were synthesized as described previously (Chirkova, Kabanova, Filimonov, Samet, et al, 2018). Compounds 13 (Filimonov et al, 2012), 14 (Chirkova et al, 2015), 16, 9m (Chirkova et al, 2016), and 17 (Chirkova, Kabanova, Filimonov, Abramov, et al, 2018) were synthesized as described previously.…”

“…The refinement was carried out with the SHELXTL program (Sheldrick, 2015). indole-5,7-diones, and the corresponding 1-hydroxy derivatives (Chirkova, 2017; have been developed and are reported in literature (Chirkova et al, 2015;Chirkova, Kabanova, et al, 2017;Chirkova, Kabanova, Filimonov, Abramov, et al, 2018;Chirkova, Kabanova, Filimonov, Samet, et al, 2018). These syntheses are based on the chlorination or bromination of 2-aryl-1-hydroxyindole-5,6-dicarbonitriles (13) It should be noted that the dibromo-N-oxides which formed as intermediates are more labile than the corresponding dichloro-Noxides, and were thus readily transformed to the corresponding 3-bromo-1-hydroxyindoles 14 and 17 by simply boiling in isopropyl alcohol.…”

“…We synthesized the NH-indoles from the corresponding NOH-indoles by the modification of the published method (Bujok, Wrobel, & Wojciechowski, 2012). This method was appropriate for the syntheses of 3-bromindoles (6a,b and 11a-c), 3-chloroindoles (9e,f), and indoles 9a-d with a yield of 45-78% from the corresponding 1-hydroxyindoles (Chirkova et al, 2016;Chirkova, Kabanova, Filimonov, Abramov, et al, 2018;Chirkova, Kabanova, Filimonov, Samet, et al, 2018).…”