Isomesityl oxide

Friedel-Crafts reactions [ALKYLPHENOLS] (Vol2) Isomesityl oxide [141-79-7]... 

Commercial mesityl oxide can contain 5—20% of the P,y-unconjugated isomer isomesityl oxide [141-79-7] (4-meth5l-4-pentene-2-one). At equihbrium, the mixture contains 91% of the a,P-mesityl oxide and 9% of the P,y-isomer (174—176). Kquilihrium is cataly2ed by either acid or alkaU. Techniques to isolate the isomers have been reported (174,176), and some physical properties of isomesityl oxide are reported ia Table 1. 

A singlet precursor has, however, been proposed for 4,4,4-triohloro-2-methyl-1-butene (17) produced in the photolysis of isomesityl oxide (18) in carbon tetrachloride solution on the basis of its all-emission spectrum (DoMinh, 1971). There remains some ambiguity, however, about the detailed route by which 17 is formed. Moreover there is other evidence suggesting that ketone photolysis in carbon tetrachloride is different CI3C. CHaCiMe) CHa CH3. CO. CHa. C(Me) CHa... 

Isodurene, t98 Isoeugenol, ml08 Isohexane, m357 Isoleucinol, a211 Isomesityl oxide, m370... 

Isomesityl oxide FALSE FALSE EALSE FALSE... 

Cryptotaenia japonica Hasskarl C. canadensis (L.) DC Japan Liu Shan Ya Er Qin (whole plant) Cryptotaenen, kiganen, kiganol, petroselic acid, isomesityl oxide, mesityl oxide, methyl isobutyl ketone, tran.v-beta-ocimene, terpinolene.48-50 For diarrhea, dysmenorrhea, rheumatism, tubercular glands. 

The photochemistry of isomesityl oxide is rather interesting in that cyclobutanol formation and type I cleavage proceed with a fair quantum yield.361 The efficiency of the process may indicate that energy transfer to the double bond is not favored.361 However, it is likely that most of the photoreaction proceeds from an excited singlet. 

Fig. 7.3 Preparative routes to acechlorplatin (1), in which isomesityl oxide (isomesox) and not mesityl oxide (mesox) is bonded to PtCl2 in a chelating fashion...

On the other hand a conjugated double bond can be shifted into an isolated position if the small amount of non-conjugated material present at equilibrium can be removed continuously from the equilibrating mixture. Isomesityl oxide (4-methyl-4-penten-2-one), for instance, can be thus prepared from mesityl oxide 11,12... 

The diacetylation of isobutene (6, R = Me) introduced either as gas, or as tert-butanol with Bronsted acids such as perchloric, tetrafluoroboric, trifluoromethanesulfonic or sulfoacetic acids) or as tert-h Ay chloride with Lewis acids such as AICI3 or FeCla proceeds via the monoacetylation products, mesityl and isomesityl oxides (10 and 9, respectively), and yields the corresponding 2,4,6-trimethylpyrylium salts (11, R = Me). 

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