72054-75-2

Upstream product

• 75-77-4 chloro-trimethyl-silane 
• 25245-34-5 1-bromo-2,5-dimethoxybenzene 
• 150-78-7 1,4-dimethoxybezene 
• 2674-34-2 1,4-dibromo-2,5-dimethoxybenzene 
• 67-56-1 methanol 
• 1004322-70-6 2-chloro-5-methoxyphenyltrimethylsilane 

Downstream Products

• 72054-78-5 2-(Trimethylsilyl)-1,1,4,4-tetramethoxy-1,4-cyclohexadiene 
• 92669-95-9 1,4-bis(trimethylsilyl)-2,5-dimethoxybenzene 

Relevant academic research and scientific papers

A predicative model for certain directed metalations, IV; The dynamic behavior of the organolithio intermediates formed by metalation of p-dimethoxybenzene (p-DMB)

Significant disproportionation between the mono- and 2,5-bis-metalated intermediates resulting from metalation of p-DMB has been observed. The best procedure for the generation of each of these intermediates involves use of an "incremental" amount of TMEDA.1.

The β effect of silicon in phenyl cations

Irradiation of chloroanisoles, phenols, and N,N-dimethylanilines bearing a trimethylsilyl (TMS) group in the ortho position with respect to the chlorine atom caused photoheterolysis of the Ar-Cl bond and formation of the corresponding ortho-trimethylsilylphenyl cations in the triplet state. The β effect of silicon on these intermediates has been studied by comparing the resulting chemistry in alcoholic solvents with that of the silicon-free analogues and by computational analysis (at the UB3LYP/6-311+G(2d,p) level in MeOH). TMS groups little affect the photophysics and the photocleavage of the starting phenyl chlorides, while stabilizing the phenyl cations, both in the triplet (ca. 4 kcal/mol per group) and, dramatically, in the singlet state (9 kcal/mol). As a result, although triplet phenyl cations are the first formed species, intersystem crossing to the more stable singlets is favored with chloroanisoles and phenols. Indeed, with these compounds, solvent addition to give aryl ethers (from the singlet) competed efficiently with reduction or arylation (from the triplet). In the case of the silylated 4-chloro-N,N- dimethylaniline, the triplet cation remained in the ground state and trapping by π nucleophiles remained efficient, though slowed by the steric bulk of the TMS group. In alcohols, the silyl group was eliminated via a photoinduced protiodesilylation during the irradiation. Thus, the silyl group could be considered as a directing, photoremovable group that allowed shifting to the singlet phenyl cation chemistry and was smoothly eliminated in the same one-pot procedure.

Synthesis of the tetracyclic carbon core of menogaril utilizing the benzannulation reaction of a Fischer carbene complex and an alkyne

The synthesis of the 2-bromoanthracyclinone 3 containing the tetracyclic core of menogaril is achieved with a strategy that is formulated around the benzannulation reaction of a Fischer carbone complex and an alkyne. This benzannulation requires a 2,5-dimethoxyphenyl carbene complex that bears an additional functional group at the 4-position that is the nascent 2-bromo substituent in 3. The evaluation of 4-bromo- and 4-trimethysilyl-substituted complexes with 1-pentyne revealed that the benzannulation was more efficient with the silyl complex. The synthesis of 3 is achieved with methoxy and acetoxy substituents at the C-9 position, which begins with the methoxy- and benzyloxy-substituted alkynes 14 and 30 that contain the A ring of the menogaril core. The closure of the last ring is accomplished by a Friedel- Crafts reaction on an in situ generated acid chloride. Adjustment of the oxidation states of the B and C rings failed according to procedures that had been developed in model studies. This was accomplished in an unexpected fashion with novel bromination reactions that occurred at a benzylic position with the C-9 methoxyl derivative and alpha to a ketone in the C-9 acetoxy derivative.

Dilithiation of Aromatic Ethers

The lithiations of anisole and all the isomeric dimethoxy- and trimethoxybenzenes with 2-5 equiv of n-butyllithium/TMEDA complex have been investigated under a variety of reaction conditions.Anisole and m-dimethoxybenzene do not undergo dilithiatian, but

Anodic Oxidation of 1,4-Dimethoxy Aromatic Compounds. A Facile Route to Functionalized Quinone Bisketals.

The anodic oxidation of 12 functionalized 1,4-dimethoxybenzene derivatives and 8 functionalized 1,4-dimethoxynaphthalenes has been studied under a variety of conditions.Many substituted 1,4-dimethoxy aromatics afford high yields of the respective quinone bisketals by single-cell anodic oxidation without accurate control of the electrode potential.Oxidizable groups offen complicate the anodic oxidation; however, in some cases protected derivatives of these functionalities can be converted to the bisketals in good yields.Aromatics containing reducible functions can besmoothly oxidized to quinone bisketals by the use of a divided cell.The current efficiencies and the effect of electrode material on selected systems are reported and discussed.