Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Reexamination Certificate
1994-03-02
2001-04-03
Geist, Gary (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
C560S219000, C568S013000, C568S016000, C568S303000, C568S308000, C423S300000
Reexamination Certificate
active
06211397
ABSTRACT:
DESCRIPTION
The present invention relates to an improved process for the preparation of &agr;-chloromethylene-triorganylphosphorane derivatives of the general formula I
in which the radicals R can be the same or different and denote
C
-organic substituents and A stands for cyano or a group
CO
-B where B denotes a
C
-organic or
O
-organic radical which has from 1 to 12 carbon atoms and is inert under chlorination conditions, by chlorination of phosphoranes of formula II
with chlorine.
It is well known that phosphoranes 11 can be chlorinated to form &agr;-chloromethylene-triphenylphosphorane derivatives (cf Houben-Weyl,
Methoden der Organischen Chemie
, Vol. E1, Georg Thieme Verlag 1982, pp 636-639).
According to G.Märkl [Chem. Ber. 94, 2996 (1961)], one procedure is to chlorinate triphenylphosphine-carbomethoxymethylene (II; A=CO—OCH
3
) with diluted chlorine gas or with phenyl iodide chloride. The drawback of this method, however, is that the product I can be obtained in a yield of not more than 50%, because phosphonium chloride IIIa
B—CH
2
—P⊕(C
6
H
5
)
3
Cl⊖ (IIIa),
is formed as a by-product.
D. B. Denney and S. T. Ross [
J. Org. Chem
. 27, 998 (1962)] describe two other methods of chlorinating compounds of type II (A=CO—CH
3
, CO—OC
2
H
5
, CO—C
6
H
5
) in methylene chloride at from −60° to −70° C., in which the chlorinating agent is a solution of chlorine in carbon tetrachloride.
In the first of these two methods, the chlorination is carried out in the presence of tertiary amines. Apart from the fact that such a method calls for elaborate engineering measures on account of the low temperatures involved, there is the risk of the formation of explosive nitrogen trichloride via a side reaction of the chlorine with the amine.
The second method operates without a base and initially yields the phosphonium chloride of I [(C
6
H
5
)
3
⊕PCH
2
—A Cl⊖] as a solid, which is then separated, dissolved in water/acetone and converted to I with sodium hydroxide. The fact that two stages are necessary to yield the product makes this method unsatisfactory.
Other known processes [G.Märkl, Chem. Ber. 95, 3003 (1962); J. Bestmann and R. Armsen,
Synthesis,
590 (1970) and EP-A 421,225] are uneconomical, because they use chlorinating agents which are either expensive [phenyl iodide chloride, sodium p-toluenesulfochloramine (chloramine-T)] or which have to be handled as solids (calcium chloride). Furthermore, their use leads to a high proportion of by-products, which must be disposed of or, if it is desired to recycle them to the process, must be regenerated at high cost.
It was thus an object of the present invention to provide a simple and industrially economical method of synthesizing &agr;-chloromethylene-triorganylphosphorane derivatives I.
Accordingly, a process for the preparation of &agr;-chloromethylene-triorganylphosphorane derivatives of the general formula I
by chlorination of phosphoranes of formula II
with chlorine has been found, wherein the chlorination is carried out in the presence of a mineral base as hydrogen chloride acceptor and the chlorine and said base are fed to the reaction mixture concurrently but separately at the rates at which they are consumed.
The process of the invention may be successfully used for the synthesis of all of the &agr;-chloromethylene-triorganylphosphorane derivatives I defined above, particularly those representatives thereof in which A is a group
CO
-B where B signifies the following:
hydrogen;
a branched or unbranched C
1
-C
4
alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl, where the alkyl group may additionally bear a C
1
-C
4
alkoxy group such as methoxy, ethoxy, isopropoxy, and tert-butoxy;
a cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl group;
a branched or unbranched C
1
-C
8
alkoxy group, in particular a C
1
-C
6
alkoxy group, such as methoxy, ethoxy, n-propoxy, 1-methylethoxy, n-butoxy, 1-methylpropoxy, 2-methylpropoxy, 1,1-dimethylethoxy, n-pentoxy, 1-methyl-butoxy, 2-methylbutoxy, 3-methylbutoxy, 2,2-dimethylpropoxy, 1-ethylpropoxy, n-hexoxy, 1,1-dimethylpropoxy, 1,2-dimethylpropoxy, 1-methylpentoxy, 2-methylpentoxy, 3-methylpentoxy, 4-methylpentoxy, 1,1-dimethylbutoxy, 1,2-dimethylbutoxy, 1,3-dimethylbutoxy, 2,2-dimethylbutoxy, 2,3-dimethylbutoxy, 3,3-dimethylbutoxy, 1-ethylbutoxy, 2-ethylbutoxy, 1,1,2-trimethylpropoxy, 1,2,2-trimethylpropoxy, 1-ethyl-i-methylpropoxy, and 1-ethyl-2-methylpropoxy, and preferably methoxy and ethoxy;
a branched or unbranched C
1
-C
6
-alkylthio group such as methylthio, ethylthio, n-propylthio, 1-methylethylthio, n-butylthio, 1-methylpropylthio, 2-methylpropylthio, 1,1-dimethylethylthio, n-pentylthio, 1-methylbutylthio, 2-methylbutylthio, 3-methylbutylthio, 2,2-dimethylpropylthio, 1-ethylpropylthio, n-hexylthio, 1,1-dimethylpropylthio, 1 ,2-dimethylpropylthio, 1-methylpentylthio, 2-methylpentylthio, 3-methylpentylthio, 4-methylpentylthio, 1,1-dimethylbutylthio, 1,2-dimethylbutylthio, 1,3-dimethylbutylthio, 2,2-dimethylbutylthio, 2,3-dimethylbutylthio, 3,3-dimethylbutylthio, 1-ethylbutylthio, 2-ethylbutylthio, 1,1,2-trimethylpropylthio, 1,2,2-trimethylpropylthio, 1-ethyl-1-methylpropylthio, and 1-ethyl-2-methylpropylthio, and preferably methylthio and ethylthio;
a C
1
-C
6
-alkoxi-C
1
-C
6
alkoxi group, in particular a C
1
-C
4
-alkoxy-C
1
-C
4
-alkoxy group, such as methoxymethoxy, ethoxymethoxy, n-propoxymethoxy, (1-methylethoxy)methoxy, n-butoxymethoxy, (1-methylpropoxy)methoxy, (2-methylpropoxy)methoxy, (1,1-dimethylethoxy)methoxy, methoxyethoxy, ethoxyethoxy, n-propoxyethoxy, (1-methylethoxy)ethoxy, n-butoxyethoxy, (1-methylpropoxy)ethoxy, (2-methylpropoxy)ethoxy, (1,1-dimethylethoxy)ethoxy, 3-(methoxy)propoxy, 2-(methoxy)propoxy, and 2-(ethoxy)propoxy, and preferably methoxymethoxy;
an aryl group, an aryloxy group, or an aryl-C
1
-C
6
-alkoxy group, where in each case the aryl group may be unsubstituted or can bear a phenyl radical or from one to three of the following radicals: C
1
-C
4
-alkyl, C
1
-C
4
-alkoxy, nitro, trifluoromethyl and/or halo;
in particular the phenyl group, a C
1
-C
4
-alkylphenyl group such as o-, m-, p-tolyl, a C
1
-C
4
-alkoxyphenyl group such as o-, m-, p-methoxyphenyl, a halophenyl group such as o-, m-, p-fluorophenyl, o-, m-, p-chlorophenyl, and o-, m-, p-bromophenyl, the o-, m-, p-nitrophenyl group, the o-, m-, p-(trifluoromethyl)phenyl group, the o-, m-, p-biphenyl group, the naphthyl group, the phenoxy group, the naphthoxy group, a phenyl-C
1
-C
6
-alkoxy group, or a naphthyl-C
1
-C
6
-alkyl group, such as benzyloxy, 1-phenylethoxy, 2-phenylethoxy, 1-phenylprop-1-yloxy, 2-phenylprop-1-yloxy, 3-phenylprop-1-yloxy, 1-phenylbut-1-yloxy, 2-phenylbut-1-yloxy, 3-phenylbut-1-yloxy, 4-phenylbut-1-yloxy, 1-phenylbut-2-yloxy, 2-phenylbut-2-yloxy, 3-phenylbut-2-yloxy, 4-phenylbut-2-yloxy, 1-(phenylmethyl)eth-1-yloxy, 1-(phenylmethyl)-1-(methyl)eth-1-yloxy, 1-(phenylmethyl)prop-1-yloxy, naphthylmethyloxy, 1-naphthylethyloxy, 2-naphthylethyloxy, 1-naphthylprop-1-yloxy, 2-naphthylprop-1-yloxy, 3-naphthylprop-1-yloxy, 1-naphthylbut-1-yloxy, 2-naphthylbut-1-yloxy, 3-naphthylbut-1-yloxy, 4-naphthylbut-1-yloxy, 1-naphthylbut-2-yloxy, 2-naphthylbut-2-yloxy, 3-naphthylbut-2-yloxy, 4-naphthylbut-2-yloxy, 1-(naphthylmethyl)eth-1-yloxy, 1-(naphthylmethyl)-1-(methyl)eth-1-yloxy, and 1-(naphthylmethyl)prop-1-yloxy, and preferably phenyl, phenoxy, benzyloxy, 2-phenylethoxy, 2-naphthyl, and 2-naphthylethoxy, and each of said phenyl and naphthyl radicals may additionally carry from 1 to 3 substituents which are inert under the conditions of the reaction.
The radicals R attached to phosphorus may be the same or different and denote, for example, branched or unbranched C
1
-C
8
alkyl groups, C
5
-C
6
cycloalkyl groups, and, in particular, phenyl, which can carry further substituents inert to the conditions of the reaction, for example C
1
-C
4
alkyl such as methyl, ethyl, and tertbutyl, C
1
-C
4
alkoxy such as methoxy,
Buschmann Ernst
Reissenweber Gernot
Schaefer Bernd
BASF - Aktiengesellschaft
Geist Gary
Keil & Weinkauf
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