TY - JOUR
T1 - Indirect Electrooxidation (an Ex-Cell Method) of Alkylbenzenes by Recycle Use of (NH4)2Ce(NO3)6 in Various Solvent Systems
AU - Torii, Sigeru
AU - Tanaka, Hideo
AU - Inokuchi, Tsutomu
AU - Nakane, Shoji
AU - Akada, Mitsuo
AU - Saito, Norio
AU - Sirakawa, Tosifumi
PY - 1982
Y1 - 1982
N2 - Indirect electrooxidation (an ex-cell method) of the side chain of alkylbenzenes has been performed by recycle use of (NH4)2Ce(NO3)6 (CAN) in various solvent systems. The side-chain oxidation of p-methoxytoluene (1) with CAN in methanol proceeds smoothly, yielding anisaldehyde (3, 94%), while use of aqueous methanol or acetic acid resulted in a mixture of 3 and the dimeric product 4 (19–35%) along with complex products (28–47%). Electrooxidation of the recovered cerium(III) salts was performed smoothly in methanol by passing 1.1–1.2 F/mol of electricity to give a reddish methanol solution of CAN, which can be used for the next oxidation of 1. The repeated use of CAN over 10 times produced the desired 3 in over 90% yields. Similarly, the oxidation of alkylbenzenes, bearing a p-methoxy group, gave the corresponding side-chain-oxidized products. In contrast, p-tert-butyltoluene (9e) could be oxidized by heating with CAN in aqueous 50% acetic acid at 85–90 °C to give p-tert-butylbenzaldehyde in over 90% yield. The regeneration of CAN after the oxidation of 9e was also accomplished by electrolysis in the aqueous 50% acetic acid system. The reaction mechanisms in connection with the nature of CAN in various solvent systems are discussed.
AB - Indirect electrooxidation (an ex-cell method) of the side chain of alkylbenzenes has been performed by recycle use of (NH4)2Ce(NO3)6 (CAN) in various solvent systems. The side-chain oxidation of p-methoxytoluene (1) with CAN in methanol proceeds smoothly, yielding anisaldehyde (3, 94%), while use of aqueous methanol or acetic acid resulted in a mixture of 3 and the dimeric product 4 (19–35%) along with complex products (28–47%). Electrooxidation of the recovered cerium(III) salts was performed smoothly in methanol by passing 1.1–1.2 F/mol of electricity to give a reddish methanol solution of CAN, which can be used for the next oxidation of 1. The repeated use of CAN over 10 times produced the desired 3 in over 90% yields. Similarly, the oxidation of alkylbenzenes, bearing a p-methoxy group, gave the corresponding side-chain-oxidized products. In contrast, p-tert-butyltoluene (9e) could be oxidized by heating with CAN in aqueous 50% acetic acid at 85–90 °C to give p-tert-butylbenzaldehyde in over 90% yield. The regeneration of CAN after the oxidation of 9e was also accomplished by electrolysis in the aqueous 50% acetic acid system. The reaction mechanisms in connection with the nature of CAN in various solvent systems are discussed.
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U2 - 10.1021/jo00348a007
DO - 10.1021/jo00348a007
M3 - Article
AN - SCOPUS:0001115324
VL - 47
SP - 1647
EP - 1652
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
SN - 0022-3263
IS - 9
ER -