Trihalogenated methyl

Note that the main metabolites detected in the non-extractable particulate matter are either oxidized at the formerly trihalogenated methyl group (DDA) or formed by the loss of this moiety (DBP, DDM). These observations suggest on the one hand a better preservation or a preferred generation of oxidized DDT metabolites within the non-extractable particulate matter, likely due to enhanced interactions of this species either with the non-extractable particulate matter or in the bound state. 

To obtain di- or trihalogenated methylated cyclohexasilanes reaction of dodecamethylcyclohexasilane with SbClg has become an established route [132, 133]. Depending on the conditions this reaction gives mixtures of 1,3-dichloro-and 1,4-dichlorodecamethylcyclohexasilane isomers or a mixture of these in addition to isomers of 1,3,5-trichlorononamethylcyclohexasilane (Scheme 16). 

In the haloform reaction, methyl ketones (and the only methyl aldehyde, acetaldehyde) are cleaved with halogen and a base. The halogen can be bromine, chlorine, or iodine. What takes place is actually a combination of two reactions. The first is an example of 12-4, in which, under the basic conditions employed, the methyl group is trihalogenated. Then the resulting trihalo ketone is attacked by hydroxide ion ... 

The haloform reaction (Problem 22.23d) is an alpha-substitution reaction in which a methyl ketone is trihalogenated at the alpha position, and the trihalomethyl group is displaced by -OH. It is a test for methyl ketones. 

The reaction takes place in two stages. In the first stage, the methyl group is trihalogenated in a stepwise fashion. In the second stage, hydroxide ion attacks the carbonyl carbon of the trihaloketone to generate the haloform along... 

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