Reaction of Aldoximes with Sodium Chloride and Oxone under Ball-Milling Conditions

Abstract

The solvent-free mechanochemical reaction has aroused increasing interest among scientists. Mechanical ball-milling can implement reactions under mild conditions, shorten the reaction time, and improve the reaction efficiency. Particularly, the most attractive characteristic of mechanochemistry is that it can alter the reaction pathway. However, few such examples have been reported so far. In this paper, we report the reaction of aldoximes with NaCl and Oxone under ball-milling conditions to afford N-acyloxyimidoyl chlorides, which are different from those of the liquid-phase counterpart.

Sustainability Assessment of Mechanochemistry by Using the Twelve Principles of Green Chemistry

“…Moreover, in 2020, a series of N-acyloxyimidoyl derivatives 17, which were inaccessible in solution, could be synthesized by neat grinding of aldoximes with NaCl and Oxone ® . [85] As commented in the beginning of this section, the stigmatization of organic solvents as reaction media is partially based on the large amounts of solvent used in relation to the solutes they dissolve. In this context, the introduction and standardization of liquid-assisted grinding (LAG) practices [11] became a turning point for expanding the green aspects of mechanochemistry.…”

“…Similarly, syntheses of adamantoid cyclophosphazanes 16 (Figure 4a), [84] and previously described 1,4‐diamino‐2‐butynes 9 [50] (Scheme 3) were made possible by implementation of neat grinding. Moreover, in 2020, a series of N ‐acyloxyimidoyl derivatives 17 , which were inaccessible in solution, could be synthesized by neat grinding of aldoximes with NaCl and Oxone ® [85] …”

Ultrasound‐Assisted Green Synthesis of 3,5‐Disubstituted Isoxazole Secondary Sulfonamides via One‐Pot Five‐Component Reaction using CaCl2/K2CO3 as Pre‐Catalyst in Water

“…With the use of direct‐ultrasonic cavitation by sonotrode material, radical or radical‐ion intermediates are more likely to be generated in water [44] . Therefore, the not isolated aldoxime, is then converted to hydroximoyl chloride with CaCl 2 and or KCl as precatalyst [45] . The hydroximoyl chloride was oxidized to unstable bi‐radical nitrile oxide, [46] promoted by the chemical effect of ultrasound, followed by a speed 1,3‐DC reaction with intermediate [ I ] as dipolarophile, to produce the corresponding intermediate [ II ] (Path A, Figure 3).…”

Mechanochemical Dimerization of Aldoximes to Furoxans

“…Aldoximes have drawn increasing attention in organic synthesis due to their easy availability, better selectivity and tolerance to various functional groups. Oxone (2KHSO 5 •KHSO 4 •K 2 SO 4 ) is a stable and non-toxic inorganic oxidant, as demonstrated in reactions involving aldoximes [39][40][41][42]. Oxone has also been employed in mechanochemical reactions [42][43][44][45].…”

“…Oxone (2KHSO 5 •KHSO 4 •K 2 SO 4 ) is a stable and non-toxic inorganic oxidant, as demonstrated in reactions involving aldoximes [39][40][41][42]. Oxone has also been employed in mechanochemical reactions [42][43][44][45]. In 2019, the Tong group reported a protocol to generate nitrile oxides through NaCl/Oxone oxidation of aldoximes [41].…”