Mechanochemical halogenation of unsymmetrically substituted azobenzenes

• Dajana Barišić,
• Mario Pajić,
• Ivan Halasz,
• Darko Babić and
• Manda Ćurić

Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69

• -bromosuccinimide (NBS) under neat grinding (NG) and liquid-assisted grinding (LAG) conditions in a ball mill [51]. Insight into the dynamics of the formation of reaction intermediates and products was obtained by in situ Raman monitoring that provided information on the nature of the catalytically active PdII

• azobenzene with NXS and Pd(OAc)2 as precatalyst in the presence of TsOH and MeCN as solid and liquid additives, respectively, led to the ortho-halogenated products relative to the azo group of the azobenzenes. In situ Raman monitoring of these reactions confirmed that the most favorable reaction pathway is

• product L2Br-I in 96% yield after 15 hours of milling (Figure 2, Table 1, entry 5). The yield of this reaction was higher than the analogous reaction in MeCN solution (90% isolated yield under the mechanochemical conditions compared to 72% in MeCN solution) [52]. In situ Raman monitoring of the

Mechanochemical Friedel–Crafts acylations

• Mateja Đud,
• Anamarija Briš,
• Iva Jušinski,
• Davor Gracin and
• Davor Margetić

Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130

• acylation reagent with aluminium trichloride. In situ Raman monitoring of reaction of phthalic anhydride with p-xylene. FCR of pyrene and phthalic anhydride. Scope of acylation reagents in FCR under mechanochemical activation conditions and comparison with other reaction conditions (isolated yields

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• spin resonance (ESR) spectroscopy; in situ Raman monitoring; mechanochemistry; quinoline; solid-state click chemistry; Introduction The copper-catalyzed azide–alkyne cycloaddition (CuAAC) represents a prime example of click chemistry. Click chemistry describes “a set of near-perfect” reactions [1] for

• difference in yields was significantly less pronounced. In situ Raman monitoring of mechanochemical click reactions In an attempt to gain a direct insight into reaction pathways of mechanochemical CuAAC reactions we repeated milling experiments 2a–2c in the preparation of the chloro-substituted product 5

• < Br < I bias, but the differences in yields for solution procedures were much more pronounced. In situ Raman monitoring of the milling processes using Cu(I) and Cu(II) catalysts revealed active involvement of copper catalysts through coordination and occurrence of strongly luminescent copper compounds

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• almost quantitative yields. The in situ Raman monitoring of a 1:2 mixture of 26 and 4-bromoaniline, which results in the formation of symmetrical bis(4-bromophenyl)thiourea 28d revealed thiocarbamoyl benzotriazole 27d as the reactive intermediate (Figure 4). Starting from 27a or 29, bis-thiourea 22a can