Propylene ureas and process for their preparation

Details Propylene ureas and process for their preparation Propylene ureas and process for their preparation

1999-07-30

2002-02-19

Wilson, D. R. (Department: 1713)

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

Organic compounds

Nitrogen attached directly or indirectly to the purine ring...

C525S328800

Reexamination Certificate

active

06348594

ABSTRACT:

The invention relates to new urea derivatives of the formula 1,
in which each of R
1
-R
7
represents a hydrogen atom or a linear or branched C
1
-C
4
-alkyl group, in particular methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl, wherein R
1
-R
7
may be identical or different, and R
8
represents a linear or branched C
1
-C
6
-alkyl group, in particular methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl. The invention also relates to a process for preparing compounds of the general formula 1. In addition, the invention relates to the use of compounds of the formula 1 for hardening hydroxyl group-containing polymers.
Reaction products of ethylene ureas and glyoxylic acid derivatives are known from U.S. Pat. No. 4,770,668. They are used to cross-link hydroxyl group-containing polymers, in particular for cross-linking hydroxyl groups within cellulose fibers. These cross-linking agents are prepared at temperatures of 100-140° C. In this temperature range oligomerization of these reactive cross-linking agents already takes place because they can also react with themselves, such as is the case, e.g., for urea/formaldehyde amino resins (R. Wegler in Houben-Weyl “Methoden der organischen Chemie”, Volume 14/2 (1963), pages 320-328). Oligomerization causes a reduction in effectiveness as cross-linking agents, particularly when cross-linking cellulose fibers, since the oligomerized cross-linking agent can no longer penetrate sufficiently far into the cellulose fiber due to its increased weight and size.
Furthermore, the high temperatures of preparation also lead to some discoloration of the products (see Examples 4.2, 4.4 and 4.5 in U.S. Pat. No. 4 770 668), which is a disadvantage when they are used to coat or impregnate colorless materials.
The object of the invention is therefore to overcome the defects in the prior art mentioned above, in particular the production of oligomeric fractions and discoloration, and to provide improved cross-linking agents based on urea which are free of the disadvantages mentioned above.
This object is achieved by the invention. The invention provides compounds of the formula 1,
in which each of R
1
-R
7
represents a hydrogen atom or a linear or branched C
1
-C
4
-alkyl group, in particular methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl, wherein R
1
-R
7
may be identical or different, and R
8
represents a linear or branched C
1
-C
6
-alkyl group, in particular methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl.
The invention also provides a process for preparing compounds of the formula 1
in which each of R
1
-R
7
represents a hydrogen atom or a linear or branched C
1
-C
4
-alkyl group, in particular methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl, wherein R
1
-R
7
may be identical or different, and R
8
represents a linear or branched C
1
-C
6
-alkyl group, in particular methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl, which is characterized in that a compound of the formula 2
in which R
9
represents a member selected from the group comprising —CHO, —CH(OH)—OR
8
and —CH(OH)
2
and R
8
is defined as above, is reacted with a urea derivative of the formula 3,
in which R
1
-R
6
are defined as above, and the reaction product obtained is optionally reacted with an alcohol of the formula X—OH, in which X represents a linear or branched C
1
-C
4
-alkyl group.
The invention also provides the use of compounds of the formula 1,
in which each of R
1
-R
7
represent a hydrogen atom or a linear or branched C
1
-C
4
-alkyl group, preferably methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl, wherein R
1
-R
7
may be identical or different, and R
8
represents a linear or branched C
1
-C
6
-alkyl group, preferably methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl, for hardening hydroxyl group-containing polymers.
As specified above, new compounds of the formula 1 according to the invention,
in which the substituents R
1
-R
7
and R
8
are defined as above are provided. Examples of compounds in accordance with the present invention which are defined by the formula 1 given above, are as follows:
methyl hydroxy-[3-(hydroxy-methoxycarbonyl-methyl)-2-oxo-tetrahydro-pyrimidin-1-yl] acetate,
methyl hydroxy-[3-(hydroxy-ethoxycarbonyl-methyl)-2-oxo-tetrahydro-pyrimidin-1-yl] acetate,
butyl hydroxy-[3-(hydroxy-butoxycarbonyl-methyl)-2-oxo-tetrahydro-pyrimidin-1-yl] acetate,
methyl methoxy-[3-(methoxy-methoxycarbonyl-methyl)-2-oxo-tetrahydro-pyrimidin-1-yl] acetate,
ethyl ethoxy-[3-(ethoxy-ethoxycarbonyl-methyl)-2-oxo-tetrahydro-pyrimidin-1-yl] acetate,
butyl butoxy-[3-(butoxy-butoxycarbonyl-methyl)-2-oxo-tetrahydro-pyrimidin-1-yl] acetate,
methyl hydroxy-[3-(hydroxy-methoxycarbonyl-methyl)-5,5-dimethyl-2-oxo-tetrahydro-pyrimidin-1-yl] acetate and,
methyl hydroxy-[3-(hydroxy-methoxycarbonyl-methyl)-5,5-dimethyl-4-isopropyl-2-oxo-tetrahydro-pyrimidin-1-yl] acetate.
Preferred examples of compounds according to the invention having the formula 1 mentioned above are methyl hydroxy-[3-(hydroxy-methoxycarbonyl-methyl)-2-oxo-tetrahydro-pyrimidin-1-yl] acetate, ethyl hydroxy-[3-(hydroxy-ethyloxycarbonyl-methyl)-2-oxo-tetrahydro-pyrimidin-1-yl] acetate and butyl hydroxy-[3-(hydroxy-butoxycarbonyl-methyl)-2-oxo-tetrahydro-pyrimidin-1-yl] acetate.
The compounds according to the invention are prepared by first reacting a compound of the formula 2
in which R
9
and R
8
are defined as above, with a urea derivative of the formula 3
in which R
1
-R
6
are defined as above.
Preferred examples of starting compounds of the formula 2 are:
methyl glyoxylate,
methyl glyoxylate hydrate,
ethyl glyoxylate,
propyl glyoxylate,
butyl glyoxylate,
methyl glyoxylate methyl-hemiacetal,
ethyl glyoxylate ethyl-hemiacetal,
propyl glyoxylate propyl-hemiacetal,
butyl glyoxylate butyl-hemiacetal.
Some of the glyoxylates and glyoxylate alkyl-hemiacetals can be obtained commercially or they may be prepared using known methods in organic chemistry such as, e.g., by esterification of glyoxylic acid with alcohols or by ozonolysis of dialkyl maleates. Hydrates such as, e.g., methyl glyoxylate hydrate and butyl glyoxylate hydrate may be prepared from methyl or butyl tartrate by oxidative C—C cleavage using periodic acid (L. D. M. Lolkema et al., Tetrahedron 50 (24) (1994) 7115-7128).
Compounds of the formula 3 are obtainable commercially such as, e.g., propylene urea. Otherwise they may be prepared using known methods in organic chemistry such as, e.g., by reacting amines with carbon dioxide or phosgene (C. Ferri, “Reaktionen der Organischen Chemie”, Georg Thieme Verlag Stuttgart, 1978, page 657). Examples of these types of substituted propylene ureas are:
5-methyl-2-oxo-tetrahydro-pyrimidine,
5,5-dimethyl-2-oxo-tetrahydro-pyrimidine and
5,5-dimethyl-4-isopropyl-2-oxo-tetrahydro-pyrimidine
(see GB patent 1 173 432).
The reaction of propylene ureas of the formula 3 with derivatives of the formula 2 can be performed in the temperature range from room temperature to elevated temperatures. In general a temperature range of 25-100° C. is expedient. Reaction temperatures in the range of 25-70° C. are preferred, in particular 50-70° C. In the temperature range of 70-100° C. no noticeable production of secondary products is observed. Reaction above 70° C., however, provides no further advantages with respect to yield or purity of the compounds.
Catalysts which are used according to the prior art for catalyzing reactions between ureas and carbonyl compounds, such as, e.g., inorganic bases such as sodium carbonate or sodium hydroxide are not required. The reaction may generally be performed without a solvent since compounds of the formula 2 are liquid. If a solvent is used, then any organic solvent which is inert towards aldehydes and ureas under the reaction conditions mentioned above are suitable; ethyl acetate or methylethyl ketone or toluene are preferred. The reaction is performed stoichiometrically, or preferably with a small excess of the more easily separ

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