61552-22-5

Upstream product

• 2785-98-0 2,5-dimethoxybenzoic acid 
• 2150-40-5 methyl 2,5-dimethoxybenzoate 

Downstream Products

• 61552-26-9 C₁₂H₁₂⁽²⁾H₃NO₄ 
• 61552-25-8 2,5-Dimethoxy-4-trideuteriomethylbenzaldehyd 
• 609337-69-1 (α,α,α-2H3)-4-benzoyloxy-2-methylphenol 
• 609337-68-0 (α,α,α-2H3)-methylhydroquinone 
• 61552-24-7 (α,α,α-2H3)-1,4-dimethoxy-2-methylbenzene 
• 61552-23-6 (α,α-2H2)-2,5-dimethoxybenzyl bromide 

Relevant academic research and scientific papers

First synthesis of (8-2H3)-(all-rac)-δ-tocopherol

Trideuterated tocopherols were needed to be used as internal standards for our study about simultaneous quantitative determination of tocopherols in foodstuffs by mass spectrometry. Whilst procedures for trideuterated α-tocopherol have been recently optimized, no method is reported as regards δ-tocopherol. Different synthetic approaches are discussed, as well as the first procedure for the synthesis of (8-2H3)-(all-rac)-δ-tocopherol. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

Mechanistic borderline of one-step hydrogen atom transfer versus stepwise Sc3+-coupled electron transfer from benzyl alcohol derivatives to a non-heme iron(IV)-oxo complex

The rate of oxidation of 2,5-dimethoxybenzyl alcohol (2,5-(MeO) 2C6H3CH2OH) by [Fe IV(O)(N4Py)]2+ (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2- pyridyl)methylamine) was enhanced significantly in the presence of Sc(OTf) 3 (OTf- = trifluoromethanesulfonate) in acetonitrile (e.g., 120-fold acceleration in the presence of Sc3+). Such a remarkable enhancement of the reactivity of [FeIV(O)(N4Py)] 2+ in the presence of Sc3+ was accompanied by the disappearance of a kinetic deuterium isotope effect. The radical cation of 2,5-(MeO)2C6H3CH2OH was detected in the course of the reaction in the presence of Sc3+. The dimerized alcohol and aldehyde were also produced in addition to the monomer aldehyde in the presence of Sc3+. These results indicate that the reaction mechanism is changed from one-step hydrogen atom transfer (HAT) from 2,5-(MeO)2C6H3CH2OH to [Fe IV(O)(N4Py)]2+ in the absence of Sc3+ to stepwise Sc3+-coupled electron transfer, followed by proton transfer in the presence of Sc3+. In contrast, neither acceleration of the rate nor the disappearance of the kinetic deuterium isotope effect was observed in the oxidation of benzyl alcohol (C6H5CH2OH) by [FeIV(O)(N4Py)]2+ in the presence of Sc(OTf) 3. Moreover, the rate constants determined in the oxidation of various benzyl alcohol derivatives by [FeIV(O)(N4Py)]2+ in the presence of Sc(OTf)3 (10 mM) were compared with those of Sc 3+-coupled electron transfer from one-electron reductants to [Fe IV(O)(N4Py)]2+ at the same driving force of electron transfer. This comparison revealed that the borderline of the change in the mechanism from HAT to stepwise Sc3+-coupled electron transfer and proton transfer is dependent on the one-electron oxidation potential of benzyl alcohol derivatives (ca. 1.7 V vs SCE).

Structural effects on the OH--promoted fragmentation of methoxy-substituted 1-arylalkanol radical cations in aqueous solution: The role of oxygen acidity

A kinetic and product study of the OH--induced decay in H2O of the radical cations generated from some di- and tri-methoxy-substituted 1-arylalkanols (ArCH(OH)R·+) and 2- and 3-(3,4-dimethoxyphenyl) alkanols has been carried out by using pulse- and γ-radiolysis techniques. In the 1-arylalkanol system, the radical cation 3,4-(MeO)2C6H3CH2OH ·+ decay at a rate more than two orders of magnitude higher than that of its methyl ether; this indicates the key role of the side-chain OH group in the decay process (oxygen acidity). However, quite a large deuterium kinetic isotope effect (3.7) is present for this radical cation compared with its α-dideuterated counterpart. A mechanism is suggested in which a fast OH deprotonation leads to a radical zwitterion which then undergoes a rate-determining 1,2-H shift, coupled to a side-chain-to-ring intramolecular electron transfer (ET) step. This concept also attributes an important role to the energy barrier for this ET, which should depend on the stability of the positive charge in the ring and, hence, on the number and position of methoxy groups. On a similar experimental basis, the same mechanism is suggested for 2,5-(MeO)2C6H3CH2OH ·+ as for 3,4-(MeO)2C6H3CH2OH ·+, in which some contribution from direct C-H deprotonation (carbon acidity) is possible. In fact, the latter process dominates the decay of the trimethoxylated system 2,4,5-(MeO)3C6H2CH2OH ·+, which, accordingly, reacts with OH- at the same rate as that of its methyl ether. Thus, a shift from oxygen to carbon acidity is observed as the positive charge is increasingly stabilized in the ring; this is attributed to a corresponding increase in the energy barrier for the intramolecular ET. When R = tBu, the OH--promoted decay of the radical cation ArCH(OH)R·+ leads to products of C-C bond cleavage. With both Ar = 3,4- and 2,5-dimethoxyphenyl the reactivity is three orders of magnitude higher than that of the corresponding cumyl alcohol radical cations; this suggests a mechanism in which a key role is played by the oxygen acidity as well as by the strength of the scissile C-C bond: a radical zwitterion is formed which undergoes a rate-determining C-C bond cleavage, coupled with the intramolecular ET. Finally, oxygen acidity also determines the reactivity of the radical cations of 2-(3,4-dimethoxyphenyl)ethanol and 3-(3,4-dimethoxyphenyl)propanol. In the former the decay involves C-C bond cleavage, in the latter it leads to 3-(3,4-dimethoxyphenyl) propanal. In both cases no products of C-H deprotonation were observed. Possible mechanisms, again involving the initial formation of a radical zwitterion, are discussed.