28750-52-9

Upstream product

• 186581-53-3 diazomethane 
• 79699-69-7 3,5,5-trimethyl-3-cyclopentene-1,2-dione 
• 78-59-1 3,5,5-Trimethylcyclohex-2-en-1-one 
• 97041-24-2 3-Chloro-3,5,5-trimethyl-cyclohexane-1,2-dione 
• 28750-42-7 Acetic acid 3-bromo-2,4,4-trimethyl-6-oxo-cyclohex-1-enyl ester 
• 4883-60-7 2-hydroxy-3,5,5-trimethylcyclohex-2-ene-1-one 
• 471-01-2 3,5,5-trimethylcyclohex-3-en-1-one 

Downstream Products

• 3938-10-1 trimethylpyrocatechol 
• 114198-57-1 2,3-Dihydroxy-4,4,6-trimethyl-cyclohexa-2,5-dienone 
• 114198-56-0 4,6,6-Trimethyl-4-cyclohexen-1,2,3-trion 

Relevant academic research and scientific papers

Chitosan-based Schiff base-metal complexes (Mn, Cu, Co) as heterogeneous, new catalysts for the β-isophorone oxidation

A new chitosan-based Schiff base was prepared and complexed with manganese, cobalt and copper. These Schiff base metal complexes were used as heterogeneous catalysts for the air oxidation of β-isophorone to ketoisophorone. The obtained complexes were characterized by means of FT-IR,1HNMR spectroscopy, elemental analysis, powder X-ray diffraction, field emission gun scanning electron microscopy, electron spin resonance spectroscopy, ICP-AES and solubility tests. Thermal properties were also investigated using thermal gravimetric analysis. Data obtained by thermal analysis revealed that these complexes showed good thermal stability. The conversion and selectivity of β-isophorone to ketoisophorone for each prepared catalyst was studied using a batch reactor and gas chromatography for product identification and quantification. The results were compared against the homogeneous bis-salicylaldehyde ethylenedi-imine-Mn catalyst. The use of methanol, acetone, methyl isobutyl ketone and n-hexane as solvent and its effect on conversion and selectivity was also investigated. Acetone was found to be a promising solvent for the β-isophorone oxidation. The role of triethyl amine and acetyl acetone in the oxidation reaction has also been investigated.

Superoxide Anion Radical (O2)-radical Mediated Base-Catalyzed Autoxidation of Enones

Seventeen variously substituted cyclohex-2-en-1-ones were prepared and reacted with superoxide anion radical (O2-radical generated from KO2/18-crown-6) in inert nonpolar aprotic media at room temperature.The 4,4,6,6-tetrasubstituted cyclohexenones (1b,1c, and 1d) proved to be totally inert,while those cyclohexenones possessing available acidic α'- or γ-hydrogens underwent O2-radical mediated base-catalysed autoxidation (BCA) generating various products depending on the nature and location of the substituents.Thus, 4,4- and 5,5-disubstituted substrates(2b, 2c, 2e, 2f and 3b, 3d, 3f-3i, respectively) gave 2-hydroxycyclohexa-2,5-dien-1-ones (7) as the major product (>80percent yield) upon aqueous acid workup while the corresponding 2-methoxy analogues 8 are obtained when the reaction is quenched with CH3I. 2,3-Epoxycyclohexanones 13 and oxidative cleavage products 11 and 12 are formed in the case of the 6,6-disubstituted systems (4a-4c); these oxidation products are accompanied by dimers 14 when the substituent on 4 is CH3 or H.Epoxide 23 is the primary isolable product in the 3,4,4-trialkyl system (5d).As expected for BCA processes, similar results were observed when these reactions were mediated by KOH (at room temperature) or KOC(CH3)3 (at -40 deg C).In the case of 6,6-diphenylcyclohex-2-en-1-one (4c), however, tert-butoxide-mediated BCA at -40 deg C yielded cyclopentene hydroxy acid 15 in addition to epoxide 13.The saturated analogue of 4c, 18, yielded primarily the corresponding saturated hydroxy acid 19, as well as several other oxidation products (20-22) depending on the reaction conditions.The mechanism of these transformations is rationalized in terms of base-induced reactions and rearrangements of the initially formed keto hydroperoxides.

IMPROVED SYNTHESIS OF 2-HYDROXY-4,4,6-TRIMETHYL-2,5-CYCLOHEXADIENONE, USEFUL AS A FLAVORING ADDITIVE

The title dienone 1, useful for modification, improvement or increasing organoleptic properties of tobacco, sucrose syrups, flavored beverages, was prepared in 40-55percent overall yield from isophorone, by chlorination of 2-hydroxy-isophorone (2), rearrangement into 6-chloro-2-hydroxyisophorone (5) and dehydrochlorination.An excellent yield of 3-chloro-2-hydroxy-4,4,6-trimethyl-2,5-cyclohexenone (12) was obtained by chlorination of 5 followed by dehydrohalogenation.

Preparation of oxacycloalkenones

Oxacycloalkenones are prepared by reacting a cycloalkenone with a base in the presence of a dioxygen source in a suitable solvent and isolating the desired product. 1-Hydroxy 2-oxa-3-oxo-Δ4 steroids are convenient synthetic precursors to 2-oxa-

THE REACTION OF ENOLS WITH SUPEROXIDE ANION RADICAL 2-.>. SYNTHESIS OF 2,3-UNSATURATED-δ-VALEROLACTONES.

3- and 4-Hydroxycoumarin (1 and 3) as well as 2-hydroxy-2,5-cyclohexadien-1-ones 5a-f were reacted with KO2/18-crown-6 in benzene.Initial deprotonation of the enol hydrogen was followed by nucleophilic attack by O2> (for 1 and 3) and/or autoxidation of the resulting anion (for 1 and 5a-e).A convenient synthesis of 2,3-unsaturated-δ-valerolactones from the corresponding 2-cyclohexen-1-ones is also described.