Process for preparing alkoxy or arylmethoxy aroxyethanes

Details Process for preparing alkoxy or arylmethoxy aroxyethanes Process for preparing alkoxy or arylmethoxy aroxyethanes

2001-02-01

2001-11-27

Richter, Johann (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Oxygen containing

C568S631000, C568S632000, C568S633000

Reexamination Certificate

active

06323376

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to alkoxy or arylmethoxy ethanes. This invention particularly concerns a process for preparation of such compounds. More particularly, the invention teaches a novel process for preparation of 2-alkoxy (or 2-arylmethoxy)-1-aroxyethanes, a class of compounds useful in a variety of diverse applications such as improved sensitizers or modifiers for thermal sensitive papers and as dispersants, emollients, and texture enhancing agents in cosmetics and lotions.
2. Description of Related Art
There are several methods described in the literature for preparing 1-benzyloxy-2-phenoxyethane represented by the structure A:
C. Berggardh [Finska Kemistsamf.Medd., 42, 76 (1933)] and E. M. Van Duzee and H. Atkins [J. Amer. Chem. Soc., 57, 147 (1935)] prepared (A) by reacting sodium 2-phenoxyethoxide with benzyl chloride. Also, C. L. Butler and A. G. Renfrew [J. Amer. Chem. Soc., 60, 1582 (1938)] and C. L. Butler and L. H. Cretcher [U.S. Pat. No. 2,172,606 (1939)] obtained (A) by treating 2-benzyloxyethyl p-toluenesulfonate with potassium phenoxide. These two methods require the preparation of one or both starting materials in a separate step and involves the use of either potassium or sodium metal that are expensive and difficult to handle in scale up operations. J. S. Bradshaw, B. A. Jones and J. S. Gebhard [J. Org. Chem., 48, 1127 (1983)] made (A) by reductive desulfurization of 2-phenoxyethyl thiobenzoate using Raney nickel. Again, the starting material thiobenzoate, prepared from not readily available 2-phenoxyethyl benzoate by thionation, makes this process not amenable to scale up. A. Goto [U.S. Pat. No. 5,179,068] described a method for preparing 1,4-bis (2-aroxyethoxymethyl) benzenes by reacting 2-phenoxyethanol with p-xylylene dichloride and aqueous sodium hydroxide using trioctylmethylammonium chloride as catalyst in toluene. Goto also, described a process for making 1,4-bis (2-aroxyethoxymethyl) benzenes in two steps starting from substituted phenol and ethylene carbonate. In the first step, the substituted phenol and ethylene carbonate were heated with catalytic amounts of potassium carbonate in chlorobenzene to generate the corresponding substituted phenoxyethanol. In the second step, the substituted phenoxyethanol was reacted with p-xylylene chloride and aqueous sodium hydroxide using trioctylmethylammonium chloride as catalyst in chlorobenzene. The success of this tandem two step process depends on the complete conversation of the substituted phenol to the corresponding substituted phenoxyethanol in the first step; otherwise, a mixture of inseparable products are formed, resulting in low yield of the desired product.
DETAILED DESCRIPTION
The present invention is a novel process for manufacturing 2-alkoxy (or 2-arylmethoxy)-1-aroxyethanes using a one-pot, two-step procedure. The novel process comprises reacting substituted or unsubstituted phenol (or naphthol) with ethylene carbonate in the presence of a first catalyst, with or without solvent, and reacting the product formed in the first step with alkyl or aralkyl halide (sulfate or sulfonate) and metal hydroxide in the presence of a second catalyst with or without solvent.
This invention teaches a process for preparing 2-alkoxy(or 2-arylmethoxy)-1-aroxyethanes. Particularly, this invention teaches a novel process for preparing 2-alkoxy (or 2-arylmethoxy)-1-aroxy-ethanes represented by the formula (I):
wherein P is selected from phenyl and naphthyl moieties.
Formula (IIA) depicts when P in the structure of Formula 1 is replaced by phenyl
Formula IIB depicts when P in the structure of Formula I is replaced by naphthyl.
In each of formulas I, IIA and IIB the substituents R
1
, R
2
and R
3
are independently hydrogen, alkyl, alkoxy, aryl, aralkyl, aralkoxy, halogen, alkoxyalkoxy and aralkoxyalkoxy; and R
4
, is independently alkoxyethyl, alkoxyethoxy and aralkoxyethoxy.
In the substituents R
1
, R
2
, R
3
and R
4
, the alkyl moieties in alkyl, alkoxy, aralkyl, aralkoxy, alkoxyalkyl, alkoxyalkoxy and aralkoxyalkoxy groups contain one through eight carbon atoms.
This invention teaches an improved process for manufacturing 2-alkoxy (or 2-arylmethoxy)-1-aroxyethanes (VIII) using a one-pot, two-step procedure from readily available materials. The process of the invention is diagrammed as follows:
The substituents P, R
1
, R
2
and R
3
are as defined previously. R
5
is either a substituted or unsubstituted phenyl or naphthyl group. The substituents on the phenyl or naphthyl groups include alkyl (C
1
-C
8
), alkoxy (C
1
-C
8
), aroxy, aralkoxy (C
1
-C
8
alkyl) and halogen. For clarity “aralkoxy (C
1
-C
8
)” herein will refer to the alkyl moiety as having from one to eight carbons.
The process comprises reacting substituted or unsubstituted phenols (or naphthols) (III) with ethylene carbonate (IV) using catalyst 1 without a solvent and reacting the product formed (V) in the first step with alkyl or aralkyl halide (sulfate or sulfonate) (VI) and metal hydroxide in the presence of catalyst 2 with or without a solvent.
By heating the phenol (or naphthol) (III) with slight excess of ethylene carbonate and the catalyst 1 without solvent, the phenol (or naphthol) is completely converted to the corresponding 2-phenoxy (or 2-naphthoxy) ethanol (V). The reaction temperature may be selected from 50° C. to 200° C. depending on the phenol (or naphthol) used. Most of the phenols (or naphthols) react in the preferred temperature range from 140° C. to 160° C.
The catalyst 1 that is suitable for this reaction include metal halides, quarternary ammonium halides and quarternary phosphonium halides. Preferred catalysts include sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammoniumiodide, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, methyltrioctylammonium chloride (aliquat 336), tetraethylphosphonium chloride, tetraethylphosphonium bromide and tetraethylphosphonium iodide. Also, a combination of quarternary ammonium salt or quarternary phosphonium salt other than halides and metal halides can be used as catalyst 1.
The intermediate (V) was then mixed with alkyl or aralkyl halide (sulfate or sulfonate) (VI), metal hydroxide (VII) and catalyst 2, heated and stirred vigorously. Powdered metal hydroxide was used in the solvent free procedure. Aqueous solution (40-50%) of metal hydroxide was used with a solvent in the solvent procedure. Preferred metal hydroxides include sodium hydroxide and potassium hydroxide and the preferred solvents are aliphatic or aromatic hydrocarbons or chlorohydrocarbons. Catalyst 2 may be either quarternary ammonium salt or quarternary phosophonium salt. Preferred catalyst 2 are tetrabutylammonium hydrogen sulfate, tetrabutylammonium halide, tetraethylammonium halide, methyltrioctylammonium choride (also known as aliquat 336) and tetraethylphosphonium halide. The reaction temperature for the second step is dependent on the solvent used. The preferred temperature range is room temperature to 55° C. for low boiling point solvents and 50-100° C. for high boiling point solvents. For the solvent free procedure 90-100° C. temperature range is preferred.
By carrying out the step 1 of this process in excess of ethylene carbonate (IV), the phenol (or naphthol) (III) is completely converted to the corresponding 2-phenoxy (or 2-naphthoxy) ethanol (V). No solvent need be used (solvent being optional but preferably omitted in Step 1) and excess ethylene carbonate and lower boiling materials are removed under reduced pressure. This complete conversion is important; otherwise, a mixture of unwanted by products are obtained by reaction of (III) with (VI). This is one of the features of this tandem process.
In step 2, (V) is converted to (VIII) using either a solvent-free or a solvent procedure. In the solvent-free procedure, a solid liquid phase

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