A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

• -flow approaches in this regard. To show the practicability of the process, a 0.12 kg scale-up operation was also performed. A Pechmann condensation in flow for the synthesis of 7-hydroxycoumarin (93) was also reported in 2012 (Scheme 19). The single-step process proved highly efficient forming the

Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds

• Vuyisa Mzozoyana,
• Fanie R. van Heerden and
• Craig Grimmer

Beilstein J. Org. Chem. 2020, 16, 190–199, doi:10.3762/bjoc.16.22

• , numerous methods for the synthesis of these compounds have been developed, examples are the Pechmann condensation [10][11], Stille coupling reaction [12], Knoevenagel condensation [13], Heck coupling reaction [14], Kostanecki reaction, Baylis–Hillman reaction [15], Michael reaction [16], Suzuki–Miyaura

One-pot preparation of 4-aryl-3-bromocoumarins from 4-aryl-2-propynoic acids with diaryliodonium salts, TBAB, and Na₂S₂O₈

• Teppei Sasaki,
• Katsuhiko Moriyama and
• Hideo Togo

Beilstein J. Org. Chem. 2018, 14, 345–353, doi:10.3762/bjoc.14.22

• -ketoesters and phenols (the Pechmann condensation) [17]. Recent studies for the metal-catalyzed reactions for the synthesis of the coumarin skeleton are as follows: the Yb(OTf)3-catalyzed microwave irradiation of phenols and propynoic acids [18], the Pd(OAc)2-catalyzed oxidative cyclocarbonylation of 2

A new synthetic protocol for coumarin amino acid

• Xinyi Xu,
• Xiaosong Hu and
• Jiangyun Wang

Beilstein J. Org. Chem. 2013, 9, 254–259, doi:10.3762/bjoc.9.30

• ; Pechmann condensation; Introduction Since α-L-(2-(7-hydroxycoumarin-4-yl)ethyl)glycine (1a, Figure 1), a fluorescent non-natural amino acid, was genetically incorporated at a defined site in proteins in living organisms for the first time by Schultz and co-workers [1] there have been more and more

• Pechmann condensation [11] from ethyl 4-chloroacetoacetate and resorcinol or its 6-halogenated derivatives (3a, 77.4% yield; 3b, 78.0%; 3c, 70.0%). By suspending compound 3 in triethyl phosphate with a catalytic amount of sodium iodide and heating the mixture under reflux, phosphonate 4 was prepared and

• under reflux in aqueous HCl solution (12 M) to completely remove the protecting groups to afford the racemic coumarin amino acid 1 (1a, 95% yield; 1b, 83%; 1c, 84.3%). This is a short and practical approach for the synthesis of coumarin amino acid 1. The Pechmann condensation was chosen to assemble the

Cyclization of ortho-hydroxycinnamates to coumarins under mild conditions: A nucleophilic organocatalysis approach

• Florian Boeck,
• Max Blazejak,
• Markus R. Anneser and
• Lukas Hintermann

Beilstein J. Org. Chem. 2012, 8, 1630–1636, doi:10.3762/bjoc.8.186

• agents [5][6]. Classical synthetic approaches for coumarins are based on the Perkin reaction or von Pechmann condensation, i.e., reactions under harsh conditions and at elevated temperatures [1]. Recent new methodologies based on CH-activation reactions still use acidic reaction media and show, in part

Synthesis of the fluorescent amino acid rac-(7-hydroxycoumarin-4-yl)ethylglycine

• Manfred Braun and
• Torsten Dittrich

Beilstein J. Org. Chem. 2010, 6, No. 69, doi:10.3762/bjoc.6.69

• an alternative route to racemic amino acid 1. Results and Discussion The synthesis outlined in Scheme 1 started from coumarinyl acetic acid 2 which is commercially available or, alternatively, readily accessible [12] through a Pechmann condensation [13] from resorcinol and diethyl