On Reuben G. Jones synthesis of 2-hydroxypyrazines

• Pierre Legrand and
• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93

• occurrence of 3,5-substituted-2-hydroxypyrazine as the major reaction product. Keywords: α-aminoamide; condensation; hydroxypyrazine; methylglyoxal; phenylglyoxal; Introduction In a recent report [1], the many ways a pyrazine nucleus is able to interact with proteins were reviewed. In this text, it was

• when considering Scheme 2. The first condensation between α-ketoaldehyde 1 (depicted in its hydrated form) and α-aminoamide 2 could lead to the four different products 5–8. The most likely to occur would be the one resulting from the condensation of the most nucleophilic group of the α-aminoamide (its

• which led to the improvements and insights described in the following. Results and Discussion The preparation of 3,5-substituted-2-hydroxypyrazines 3 is usually undertaken [6][13][18][19][20][21][22][23][25][26][27][28][31] as follows. The α-ketoaldehyde 1 and the hydrochloride salt of the α-aminoamide

Enantioconvergent catalysis

• Justin T. Mohr,
• Jared T. Moore and
• Brian M. Stoltz

Beilstein J. Org. Chem. 2016, 12, 2038–2045, doi:10.3762/bjoc.12.192

• halide (e.g., (±)-16). Subsequently, the achiral radical combines with the chiral Cu catalyst and undergoes an enantioselective bond-formation step in conjunction with the carbazole nucleophile to form α-aminoamide 18. This report fuses both enantioconvergent and photoredox catalysis, two powerful and

Studies on the interaction of isocyanides with imines: reaction scope and mechanistic variations

• Ouldouz Ghashghaei,
• Consiglia Annamaria Manna,
• Esther Vicente-García,
• Marc Revés and
• Rodolfo Lavilla

Beilstein J. Org. Chem. 2014, 10, 12–17, doi:10.3762/bjoc.10.3

• (Table 1, entry 10), without traces of the corresponding α-aminoamide. Different types of activated substrates displaying C=N bonds (N-sulfinylimines, oximes and hydrazones) were studied, but none of them reacted productively with isocyanides under the described conditions. Finally, the reaction with

• of such groups linked to the carbon of the imine did not seem to disturb their reactivity (Table 1, entries 1–8). Interestingly, the reaction of glyoxylate imine (Table 1, entry 9) with tert-butyl isocyanide led to the formation of minor amounts of the azetidine adduct 3i (9%) whereas the α

• -aminoamide 7 (34%) was the major component. The formation of amidoamides has been reported in the p-toluenesulfonic acid-catalyzed interaction of anilines, amines and isocyanides [8]. On the other hand, the reaction of the same imine with cyclohexyl isocyanide gave azetidine 3j (34%) in a selective manner