28195-45-1

Upstream product

• 67-56-1 methanol 
• 2243-32-5 pentamethylbenzoic acid 
• 856182-13-3 3-methyl-1-pentamethylphenyl-but-2-en-1-one 
• 6590-36-9 2,3,4,5-Tetramethyl-bicyclo[4,2,0]octa-1,3,5-trien-7-on 
• 124-41-4 sodium methylate 
• 91416-41-0 (2,3,4,5-Tetramethyl-6-methylene-cyclohexa-2,4-dienylidene)-methanone 
• 108-31-6 maleic anhydride 
• 186581-53-3 diazomethane 

Downstream Products

• 31575-31-2 2,3,4,5-Tetramethyl-6-nitrooxymethyl-benzoic acid methyl ester 

Relevant academic research and scientific papers

Quantum amplified isomerization in polymers based on triplet chain reactions

(Graph Presented) Photoinitiated triplet quantum amplified isomerizations (QAI) of substituted Dewar benzene derivatives in polymeric media are reported. The quantum efficiencies and the ultimate extents of reactant-to-product conversions increase significantly with the incorporation of appropriate co-sensitizers; compounds whose triplet energies are similar to or lower than that of the sensitizer and close to that of the reactant. These co-sensitizers serve to promote chain-propagating energy transfer processes and thereby increase the action sphere of photosensitization. Isomerization quantum yields increase, as predicted, with increasing concentrations of the reactants and the co-sensitizers. Chain amplifications as large as ～16 and extents of conversion that approach 100% have been achieved. Mechanistic schemes are proposed to account for the dynamics of the inherent energy transfer processes and provide a predictively useful model for the design of a new class of photoresponsive polymers based on changes in the refractive index of the materials.

Regioselectivity of the Base-Induced Ring Cleavage of 1-Oxygenated Derivatives of Cyclobutabenzene

Oxy anions 3 generated from 1,2-dihydrocyclobutabenzen-1-ones 1 through addition of a charged nucleophile or from 1-hydroxy-1,2-dihydrocyclobutabenzenes 2 by deprotonation with base lead to stable products through distal and/or proximal cleavage of the strained four-membered ring via benzyl carbanion 4 and/or aryl carbanion 5. A systematic study of this process reveals the relative stability of the two isomeric carbanions 4 and 5 as a key factor in determining the course of the ring-cleavage reaction. While benzyl carbanions 4 can be trapped with carbon electrophiles, attempts at trapping aryl carbanions 5 with electrophiles other than H+ failed. In protic solvents, the magnesium salt of the tertiary alcohol 2 shows an increased rate of proximal cleavage as compared to its alkali salts. From this, we conclude that, in contrast to benzyl carbanions 4, free aryl carbanions 5 are of transient existence only. Proximal C,C-bond cleavage seems to occur either through protonation of 5 from a fast, reversible equilibrium 3?5 in which 3 strongly predominates, or in protic solvents possibly even through a rate-limiting protonation of 3 at the aromatic C-atom, bypassing free anion 5 altogether. Thus, additional factors other than just the relative stability of isomeric carbanions 4 and 5 are of importance in determining the regiochemistry of the base-induced C,C-bond cleavage in ketones 1 and in alcohols 2.

Oxidation of Aromatic Compounds. II. Oxidation of Methyl Derivatives of Benzoic Acid and Acetophenone in the System HSO3F-PbO2

Low-temperature oxidation of methyl derivatives of benzoic acid and acetophenone in the system HSO3F-PbO2 proceeds with intermediate formation of radical cations and results in replacement of hydrogen atom in methyl group or benzene ring.The reaction allows preparation of various substituted derivatives of benzyl alcohols and alkylated phthalides.

THERMAL ADDITION REACTIONS TO BENZOCYCLOBUTENONES STUDIED BY FLASH PHOTOLYSIS

Ortho-quinoid vinylketenes 2 have been generated thruogh flash photolysis of benzocyclobutenones 1.A kinetic study of intermolecular addition reactions of 2 competing with the recyclization 2 -> 1 reveals strikingly different substituent effects for the addition of methanol and of dienophiles.