Piperonylic Acid

Abstract

Piperonylic acid reactant: Sixty grams (0.4 mole) of piperonal product: piperonylic acid

Synthesis of N‐(2‐chloro‐3,4‐dimethoxybenzylideneamino)guanidinium acetate [α‐14C]

“…However, an alternative approach (Scheme 1) involving the oxidative decarboxylation of the corresponding carboxylic acid 3 was successful. The aldehyde 2 was readily oxidized using classical methods 9 giving the acid 3 in 76% yield and high purity, while the acid could be used directly in the next key step. Thus, the decarboxylation was accomplished in an easy and clean manner using Pb(OAc) 4 /I 5d and catalytic amounts of AIBN in CCl 4 to afford 2-chloro-3,4-dimethoxy-1-iodobenzene (4) in good yield (72%) after column chromatography.…”

Comment on “Catalyst- and additive-free sunlight-induced autoxidation of aldehydes to carboxylic acids” by H. Shi, J. Li, T. Wang, M. Rudolph and A. S. K. Hashmi, Green Chem., 2022, 24, 5835

“…Before the 1990s, the concept of green chemistry did not exist, and straightforward and selective methods for the oxidation of benzaldehyde were investigated. [9][10][11][12][13][14][15] It should be noted that, even using stoichiometric oxidants, the reported isolated yields were below 95% [9][10][11][12][13][14][15] (see also point 3).…”

Preparative microdroplet synthesis of carboxylic acids from aerobic oxidation of aldehydes

“…The oxidation of aldehydes to carboxylic acids has been of long-standing interest in synthetic organic chemistry, 14 and is an industrially important process. 15 Compared to different oxidizing reagents used in conventional methods such as Cr( iv )-based Jones oxidation, 16 , 17 Ag( i )-based Tollen's reaction, 18 and Cu( ii )-based Fehling's reaction, 19 molecular oxygen is considered as an ideal oxidant because it is inexpensive, environmentally friendly, 20 and exhibits highly atom-efficient oxidation per weight (100% atom efficiency). 21 Methods to achieve direct and efficient oxidation of aldehydes to carboxylic acids using molecular oxygen as the oxidant under mild conditions are relatively scarce and highly needed, 22 although recently, progress has been made in the development of less expensive transition-metal catalysts for oxidation of aldehydes to carboxylic acids in the bulk.…”