Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
1999-09-21
2001-05-15
Aulakh, C. S. (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C252S405000, C252S399000, C252S397000, C430S202000, C430S235000
Reexamination Certificate
active
06232469
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to novel 4-acylamino-2,2,6,6-tetramethylpiperidine derivatives. More particularly, it relates novel 4-acylamino-2,2,6,6-tetramethylpiperidine derivatives which are useful as antioxidants and antioxidants containing the same.
BACKGROUND OF THE INVENTION
It is widely known that dyes (e.g., azo dyes, azomethine dyes and anthraquinone dyes), colorants or polymers (for example, rubbers and plastics) are deteriorated by oxidative reactions in which oxygen in air participates. Accordingly, there have been developed various deterioration inhibitors typified by various antioxidant compounds such as phenols and hydroquinones as disclosed, e.g., in JP-A-59-87456, JP-A-59-180557 and JP-A-59-189342 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”).
However, none of these conventional deterioration inhibitors is satisfactory in the performance of preventing colorants, dyes, synthetic polymers, etc. from deterioration. Thus, it has been required to develop novel antioxidants.
SUMMARY OF THE INVENTION
An object of the present invention is to provide novel 4-acylamino-2,2,6,6-tetramethylpiperidine derivatives as antioxidants.
Another object of the present invention is to provide antioxidants containing novel 4-acylamino-2,2,6,6-tetramethylpiperidine derivatives.
A further object of the present invention is to provide novel 4-acylamino-2,2,6,6-tetramethyipiperidine derivatives which are useful as antioxidants for polymers.
The present inventors have conducted intensive studies. As a result, they have developed 4-acylamino-2,2,6,6-tetramethylpiperidine derivatives represented by the following formula (A) and found out that these derivatives exhibit excellent antioxidant effects:
wherein R
1
represents a hydrogen atom, a hydroxyl group, an oxyradical group, an aliphatic group, an acyl group, an aliphatic oxy group or an acyloxy group; and R
2
represents an aliphatic group having at least 3 carbon atoms and at least two hydroxyl groups.
DETAILED DESCRIPTION OF THE INVENTION
Now, the formula (A) will be illustrated in greater detail.
When a group given herein contains an aliphatic moiety, the aliphatic moiety may be either a linear, branched or cyclic one. Also, it may be either a saturated or unsaturated one. Examples thereof include alkyl, alkenyl, cycloalkyl and cycloalkenyl groups which may have substituent(s). When a group given herein contains an aryl moiety, the aryl moiety may be either a monocyclic or fused ring one which may have substituent(s). When a group given herein contains a heterocyclic moiety, the heterocyclic moiety has heteroatom(s) (for example, nitrogen, sulfur or oxygen atoms) in its cycle. It is either a saturated or unsaturated one. Also, it is either a monocyclic or fused ring one which may have substituent(s).
The term “substituent” as used herein means any substitutable group exemplified by aliphatic, aryl, heterocyclic, acyl, acyloxy, acylamino, aliphaticoxy, aryloxy, heterocyclic oxy, aliphatic oxycarbonyl, aryloxycarbonyl, heterocyclic oxycarbonyl, carbamoyl, aliphatic sulfonyl, arylsulfonyl, heterocyclic sulfonyl, aliphatic sulfonyloxy, arylsulfonyloxy, heterocyclic sulfonyloxy, sulfamoyl, aliphatic sulfonamido, arylsufonamido, heterocyclic sulfonamido, aliphatic amino, arylamino, heterocyclic amino, aliphatic oxycarbonylamino, aryloxycarbonylamino, heterocyclic oxycarbonylamino, aliphatic sulfinyl, arylsulfinyl, aliphatic thio, arylthio, hydroxyl, cyano, sulfo, carboxyl, aliphatic oxyamino, aryloxyamino, carbamoylamino, sulfamoylamino, sulfamoylcarbamoyl, carbamoylsulfamoyl, dialiphatic oxyphosphonyl and diaryloxyphosphonyl groups and halogen atoms.
R
1
, represents a hydrogen atom, a hydroxyl group, an oxyradical group, an aliphatic group (for example, optionally substituted alkyl or alkenyl, preferably alkyl and still preferably alkyl having 1 to 8 carbon atoms such as methyl, ethyl, propyl or octyl), an acyl group (for example, optionally substituted alkylcarbonylamino, alkenylcarbonylamino or arylcarbonylamino, preferably alkylcarbonylamino and still preferably alkylcarbonylamino having 1 to 7 carbon atoms in the alkyl moiety such as acetyl, propionyl orbutyryl), analiphatic oxy group (for example, optionally substituted alkoxy or alkenoxy, preferably alkoxy and still preferably alkoxy having 1 to 8 carbon atoms such as methoxy, ethoxy, propoxy or octyloxy) or an acyloxy group (for example, optionally substituted alkylcarbonyloxy, alkenylcarbonyloxy or arylcarbonyloxy, preferably alkylcarbonyloxy and still preferably alkylcarbonyloxy having 1 to 7 carbon atoms in the alkyl moiety such as acetoxy or propionyloxy). R
2
represents an aliphatic group having at least 3 carbon atoms and at least two hydroxyl groups (alkyl or alkenyl optionally having substituent(s) other than the hydroxyl groups, preferably alkyl and still preferably alkyl having 3 to 7 carbon atoms and 2 to 6 hydroxyl groups such as 1,3-dihdyroxy-2,2-ddmethylpropyl or 1,2,3,4,5-pentahydroxypentyl).
From the viewpoint of the effects of the present invention, it is preferable that R
1
is a hydrogen atom, a hydroxyl group, an oxyradical group or an alkyl group, still preferably a hydrogen atom or an oxyradical group and a hydrogen atom in the most desirable case.
Next, particular examples of the compounds of the present invention will be illustrated, though the present invention is not restricted thereto.
(lactone employed as starting material:
(±)-&agr;-hydroxy-&ggr;-butyrolacotne)
(lactone employed as starting material:
D-(+)-glucono-1,5-lacotne)
(lactone employed as starting material:
DL-pantoyllacotne)
(lactone employed as starting material:
&ggr;-D-galactonolacotne)
(lactone employed as starting material:
&agr;-D-glucoheptonic-&ggr;-lactone)
(lactone employed as starting material:
L-ascorbic acid)
(lactone employed as starting material:
D-glucurono-6,3-lacotne)
(lactone employed as starting material:
DL-pantoyllactone)
(lactone employed as starting material:
D-(+)-glucono-1,5-lacotne)
(lactone employed as starting material:
DL-pantoyllactone)
(lactone employed as starting material:
(±)-&agr;-hydroxy-&ggr;-butyrolacotne)
(lactone employed as starting material:
DL-pantoyllacotne)
(lactone employed as starting material:
DL-pantoyllacotne).
As the 2,2,6,6-tetramethylpiperidine skeleton of the compounds represented by the formula (A) according to the present invention, 4-amino-2,2,6,6-tetramethylpiperidine, 4-amino-2,2,6,6,-tetramethylpiperidin-1-oxyl free radical, etc. are marketed and easily obtained. The compounds of the formula (A) can be synthesized by various reactions such as amidation, alkylation, oxidation, reduction, etc. using these starting materials. As a general method for introducing the group R
2
in the formula (A), it is convenient and preferable to perform amidation by reacting an amine compound and a lactone compound by reference to the method described in “Shin Jikken Kagaku Koza (New Studies on Experimental Chemistry) ”, vol. 14, p. 1150 (1977), MARUZEN Co., Ltd. As the starting lactone compound, D-(+)-glucono-1,5-lactone, DL-pantoyllactone, etc. can be easily obtained. More particularly speaking, an amino compound and a lactone compound are reacted in an alcoholic solvent or a sulfolane solvent at room temperature to under reflux. As an alkylation reaction for introducing the group R
1
in the formula (A), it is preferable to reflux formalin or to react an alkyl halide with potassium carbonate in dimethylformamide at about 100° C. Moreover, the acylation is preferably exemplified by a reaction with an acid anhydride or an oxyl free radical reaction; the hydroxylation is preferably exemplified by a method in accordance with Helv. Chem. Acta (1980)63, 1407 with the use of hydrogen peroxide; the alkoxylation is preferably exemplified by a reaction between an alkyl halide and t-butoxypotassium; and the acyloxylation is preferably exemplified by a reaction of the above-mentioned hydroxyl groups with an acid anhydride without resort to any solvent.
Th
Kamio Takayoshi
Seto Nobuo
Aulakh C. S.
Birch & Stewart Kolasch & Birch, LLP
Fuji Photo Film Co. , Ltd.
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