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|Title: ||Novel aminoalkylation reactions of electron-rich aromatic compounds|
|Authors: ||Wilkins, Robert F.|
|Issue Date: ||1990|
|Publisher: ||© Robert F. Wilkins|
|Abstract: ||It has been shown that preformed methyleneiminium salts react readily
with N-substituted pyrroles, and both furan and 2-methylfuran, to give
Mannich bases in good yields. Furan itself has previously been reported
not to undergo the Mannich reaction. Thus furan reacts with
N,N-dimethy(methylene)iminium chloride to give 2-(N,N-dimethylaminomethyl)furan.
Modification of these experimental methods has enabled Mannich reactions
to be carried out in non-protic solvents whilst avoiding high concentrations
of acid. Thus bis-(dialkylamino)methanes (aminals) and alkoxydialkyl-aminomethanes
(aminol ethers) were interacted with sulphur dioxide or
chlorosilanes to generate reactive aminoalkylating species "in situ". Such
species were then used to functionalise aromatic substrates.
It has been demonstrated that a number of cyclic aminals and aminol ethers
will function as Mannich reagents in "in situ" reactions. This type of reaction
enables two functional groups to be simultaneously introduced into
nucleophilic substrates. Thus 2-methylfuran will react with
1,3-dimethylimidazolidine in the presence of trichloromethylsilane to give
N,N'-dimethyl-N-(5'-methyl-2'-furylmethyl)ethylene diamine which
contains both secondary and tertiary amine groups. Similarly interaction
of N-methylindole with 3-methyl-I,3-oxazolidine and a chlorosilane
yields 3-(N'-2'-hydroxyethyl-N'-methylaminomethyl)-N -methylindole,
which has a tertiary amine substituent and a terminal alcohol functionality.
The use of t-butylchlorodimethylsilane as the activating agent enables the
said hydroxyl group to be simultaneously protected as its t-butyl-dimethylsilylether.
5-methyl-2-(N-methylaminomethyl)furan was prepared by the removal
of the hydroxyethyl substituent from 2-(N-2'-hydroxyethyl-N-methylaminomethyl)-
The use of thionyl chloride as an activating reagent has enabled us to prepare
methyl 2-(5'-methyl-2'-furyl)-2-(N -2"-chloroethyl-N -methylamino)-acetate,
a racemic aryl glycine derivative, from
2-methoxycarbonyl-3-methyl- 1,3-oxazolidine, in a reaction with
|Description: ||A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.|
|Appears in Collections:||PhD Theses (Chemistry)|
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