Aromatic 2-methylcyclohexanone

Bhattacharyya et al. reported the first total synthesis of clausenalene (90) to establish its structure (99). This total synthesis uses Japp-Klingemann and Fischer-Borsche reactions as key steps. The phenyl hydrazone 1000 required for the transformation to 1-0x0-tetrahydrocarbazole 1001 under Fischer-Borsche conditions was obtained by condensation of 2-hydroxymethylene-5-methylcyclohexanone (999) with diazotized 3,4-methylenedioxyaniline (998) using Japp-Klingemann conditions. Wolff-Kishner reduction of 1001 furnished 3-methyl-6,7-methylenedioxy-l,2,3,4-tetrahydrocarbazole (1002), which, on aromatization wifh 10% Pd/C in decalin, afforded clausenalene (90) (99) (Scheme 5.143). 

True solvents are considered to be those solvents that provide resin solutions which can be diluted to infinity without resin precipitation. True solvents for epoxies include MEK, diacetone alcohol, methylcyclohexanone, and most glycol ethers and their acetates. Acetone, not a true solvent, can be used to prepare 40% solutions of high-MW DGEBA epoxy resin, but not a 20% solution. Aromatic solvents such as toluene and xylene, as well as simple alcohols, such as isopropyl and n-butyl alcohol, are not active solvents for DGEBA resins however, they can be used in combination with other solvents to improve solubility. 

Because one of the rings is aromatic, it is clear which ring in the product is derived from which ring in the reactants. The carbon atom that bridges the two rings in the products must be derived from the carbonyl group of benzaldehyde. The two a protons from methylcyclohexanone and the carbonyl oxygen are lost as water. 

The preponderance of the A6 isomer in an equilibrium mixture of the pyrrolidine enamine of 3-methylcyclohexanone can be attributed to A(1,2) strain (2.5-3.3 kJ mol-1) between the quasiequatorial methyl group and the vinylic hydrogen atom in the A1 isomer75-77. Equilibrium between the A1 and A6 isomers of 3-substituted enamines takes place very readily at low temperatures78-80. When conjugation of the enamine with a 3-substituted aromatic ring is made possible, the A1 isomer is the predominant isomer81-89. 

The most widespread photoresists of negative tone consist of organic polymers and aromatic diazides dissolved in an organic solvent. In 1970-1980, the photoresists were based on cyclized rubber 10 and 2,6-di (4 -azidobenzylidene) -4-methylcyclohexanone... 

Ans. (a) 3-Methylcyclohexanone. (b) Common names are used for ketones where one (or both) substituent(s) attached to the carbonyl carbon is (are) cyclic (aromatic or nonaromatic) 2-chloro-phenyl ethyl ketone or o-chlorophenyl ethyl ketone, (c) 4-Methyl-2-heptanone. (d) 2-Chloro-cyclohexanecarbaldehyde. 

In HjSO -AcjO-HOAc, 2-methylcyclohexanone inter alia) was aromatized to yield o-cresyl acetate in 90% yield. 

Iridation by cleavage of the C—H bond is mainly limited to an sp C—H bond. This is an important route to iridacycles. The synthesis of aromatic compounds via ortho iridation was mentioned previously. Cleavage at a sp C—H bond leading to quinoline has been reported [36]. The reaction of 2-methylcyclohexanone oxime with diphenylacetylene gave quinoline 59 (Scheme 5.22). A key intermediate is iridacycle 60, generated by the chelation-assisted cleavage of a sp C—H bond. Insertion of alkyne into an Ir—C bond followed by aromatization gives quinoline 59. 

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