Methyl terf-butyl ketone

Upon treatment with mineral acids, 2,3-dimethyl-2,3-butanediol (often called pinacol) is converted into methyl terf-butyl ketone (often called pinacolone). The... 

It is important to include the full life cycle. A good recent example is the case of methyl terf-butyl ketone (MTBE). MTBE can be produced using an efficient catalytic distillation process and it performs well as a fuel additive. However, the combination of three facts [carcinogenic potency, significant solubility in water and difficulty in... 

The surprisingly-rapid reactions observed for ketones containing ferf-butyl groups (such as methyl terf-butyl ketone and di-terf-butyl ketone) have two implications ... 

KETENE, feef-butylcyano-, 55, 32 37, 38 Ketene 1 1-dimethylpropylcyano-, 55, 38 7-KETOESTERS, 58, 79, 81, 82 7-KETOESTERS TO PREPARE CYCLIC DIKETONES, 58, 83 KETONE terf-butyl phenyl, 55, 122 Ketone, methyl ethyl- 55, 25 Ketone, methyl vinyl, 56, 36 KETONES, acetylenic, 55, 52 Ketones, alkylation of, 56, 52 KETONFS aromatic, aromatic hydrocarbons from 55, 7... 

To a suspension of NaNH2 (125 g, 3.2 mol) in benzene (250 mL) was added dropwise at rt over a period of 2.5 h terf-butyl methyl ketone (160 g, 1.6 mol) dissolved in benzene (750 mL). This suspension was heated under reflux with vigorous stirring for 35 min. The mixture was allowed to cool to rt and chloro-methyloxiranc (84.6 g, 0.91 mol) was added dropwise over 45 min. The reaction was exothermic. The mixture was cooled with an ice bath in order to keep the temperature at 50 C. After addition of chloro-methyloxirane, stirring was continued for 2 h, the mixture was then slowly poured onto crushed ice (1000 g) and acidified with HC1. The organic phase was decanted, washed with H20 and dried (Na2S04). Distillation under reduced pressure gave the product yield 71 g (50%) bp 138°C/15 Torr. 

The chemical reactivities of ketones follow the order terf-butyl > ethyl > methyl, which is the stability order for the cations or radicals of these groups. This suggests that the mechanisms of ketone decomposition involve a rate-determining migration of an electrophilic alkyl moiety of the ketone, perhaps leading to the production of acyl and alkoxy radicals from some partially oxidized intermediate. 

Whereas cyclopropyl methyl ketone was hydrosilylated with an enantioselec-tivity of 81% ee, the increase of the steric demand of one of the alkyl groups led to improved enantiomeric excesses, reaching 95% ee in the case of terf-butyl methyl ketone. Linear-chain n-alkyl methyl ketones, which are particularly challenging substrates, were reduced with good asymmetric induction, such as in the case of 2-octanone (79% ee) and even 2-butanone (65% ee) [58]. 

Special care must be taken for water soluble analytes such as ketones, alcohols, etc. It is advisable to purge them at an elevated temperature of 80°C. Despite the boiling points and vapor pressure of fuel oxygenated compoimds (such as methyl-ferf-butyl ether, ethyl-terf-butyl ether, ethyl-butyl alcohol, etc.), frequent problems are encountered as a result of their high solubility in water. Thus the method performance must be checked. The use of an appropriate analytical column and heating to 80°C rather than ambient temperature are proposed modifications in EPA Method 5030C. 

Initial attempts by Fujita et al. to effect alkylation at the methyl group of 2-methyl-4-carbo-terf-butoxylcarbonyloxazole (116) entailed blockage of the 5 position with a trimethylsilyl group by preparation of 133 (76). Treatment of 133 with n-butyllithium, rm-butyllithium, and sodium hydride, followed by methyl iodide in each case, yielded the ketone 134, the 5-rm-butyl derivative 135, and the starting ester 116, respectively, with no evidence of deprotonation-alkylation of the methyl group (76). Resort was therefore made to halo-... 

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