Catalytic utilization of converter gas – an industrial waste for the synthesis of pharmaceuticals

Abstract

From waste to value. An efficient and convenient ruthenium-catalyzed reduction of aromatic nitro compounds using converter gas as a reducing agent to produce valuable pharmaceuticals has been developed.

Reductive coupling of nitroarenes with carboxylic acids – a direct route to amide synthesis

“…25 It is noteworthy that in contrast to the previous work, addition of water did not improve the results (entry 9 in Table 1 and Table S3 in the ESI†). 25…”

“…The previous protocol for this reaction required at least 10 equivalents of acid. 25 It is noteworthy that in contrast to the previous work, addition of water did not improve the results (entry 9 in Table 1 and Table S3 in the ESI †). 25 However, here we faced reproducibility issues related to catalyst stability in the presence of carboxylic acids.…”

“…Chlorinated solvents do not fit the reaction. Noteworthily, in contrast to the previous work, 25 it is possible to lower the acid amount to 1.5 equivalents. However, the reaction under these conditions demonstrated lower reproducibility.…”

“…, a mixture of carbon monoxide, carbon dioxide and nitrogen. 25 This process involved the use of only gaseous reagents leading to simple product isolation. In this case, carbon dioxide was used as an activator for the substrate, as the process yields in the absence of CO 2 (with pure CO) were lower.…”

“…Recently, we developed an atom-economical way for the coupling of nitroarenes with carboxylic acid using the converter gas as a reducing agent, i.e., a mixture of carbon monoxide, carbon dioxide and nitrogen. 25 This process involved the use of only gaseous reagents leading to simple product isolation. In this case, carbon dioxide was used as an activator for the substrate, as the process yields in the absence of CO 2 (with pure CO) were lower.…”