Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system
Reexamination Certificate
2000-07-31
2001-10-23
Shah, Mukund J. (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Four or more ring nitrogens in the bicyclo ring system
C544S204000
Reexamination Certificate
active
06307046
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an improvement of a method for modifying melamine derivatives by introducing substituents on the N atom of melamine or an N-substituted melamine derivative, characterized by heating melamine or an N-substituted melamine derivative and an alcohol in the presence of a metal catalyst and hydrogen to allow reaction.
A first aspect of the present invention relates to a method for modifying melamine derivatives by introducing substituents on the N atom of melamine or an N-substituted melamine derivative, characterized by heating melamine or an N-substituted melamine derivative and an alcohol in the presence of a mixed catalyst comprising a hydrogenation catalyst and a dehydrogenation catalyst, and hydrogen to allow reaction.
A second aspect of the present invention relates to a method for modifying melamine derivatives by introducing a substituent on the N atom of melamine or an N-substituted melamine derivative, characterized by heating melamine or an N-substituted melamine derivative and an alcohol in the presence of a hydrogenation catalyst and hydrogen with addition/coexistence of a metal to allow reaction.
The N-substituted melamine derivatives obtained by the modification method of the present invention, which the method involves incorporation of a substituent group to the amino group on a triazine ring carbon atom of melamine, are useful compound groups that are used widely as various fine chemical intermediates for agricultural chemicals, medicines, dyes, paints and the like, as forming components for various resin materials, in particular an aminoplast, and as a flame retardant.
BACKGROUND ART
From the interest on substituted triazines as materials for various resin and fine chemicals, various synthetic methods and derivatives thereof have been developed.
As the synthetic method, for example, reported are various novel synthetic methods for catalytically obtaining N-substituted triazine derivatives using industrial starting materials, such as the synthetic method by amino exchange reaction between melamine and a corresponding amine derivative [as described in U.S. Pat. No. 4,618,676 (1986), U.S. Pat. No. 4,668,785 (1987), etc.], the method for obtaining an N-substituted triazine derivative using a 1,3,5-triazine derivative, typically represented by melamine, as a starting material and an alcohol [WO95/03287 (corresponding to JP-A Hei8-27128)], the method for obtaining N-substituted triazine derivatives using an aldehyde and a ketone [WO95/30662 (corresponding to JP-A Hei8-193071)], and the method for obtaining N-substituted triazine derivatives using an olefin (JP-A Hei8-27125), proposed by the present inventors. Also, reported are the method for obtaining N-substituted triazine derivatives proposed by the present inventors by reacting a 1,3,5-triazine derivative as a starting material with an alcohol in the presence of a metal catalyst and hydrogen [as described in WO97/24338 (corresponding to JP-A Hei10-231291), etc.]
The methods described in U.S. Pat. Nos. 4,618,676 (1986) and 4,668,785 (1987) and the like perform reactions at elevated temperatures using acid catalysts and are extremely excellent methods for introducing general alkyl groups or a hydroxyethyl group. However, as for amines, generally those that are available at low costs are limited so that there is a limitation on the starting material for introducing various substituents according to this method, resulting in that only limited compounds can be industrially supplied at low costs.
The above-described production methods by the present inventors are methods using starting materials that can be available at low costs on an industrial scale. In particular, those methods using alcohols are recommendable methods from the viewpoints of the kind, price, stability and the like of the starting material. However, sometimes a high temperature and a long time are required depending on the reactivity of the substance and there may occur problems, such as induction of side reactions that will not be observed usually and low productivity.
Therefore, it has now been desired to develop a method for modifying melamine derivatives that can use alcohols that can be available at low costs on an industrial scale and is further improved industrially.
DISCLOSURE OF THE INVENTION
As a result of intensive investigation by the present inventors to solve the above production methods, in a first invention, the present invention having practically applicable reactivity and productivity and being widely applicable to various alcohols has been completed, in which a melamine derivative and an industrially inexpensive alcohol are reacted in the presence of a mixed catalyst comprising a hydrogenation catalyst and a dehydrogenation catalyst, and hydrogen gas to introduce a substituent on the amino group of the melamine derivative.
In a second invention, the present invention having practically applicable reactivity and productivity and being widely applicable to various alcohols has been completed, in which a melamine derivative and an industrially inexpensive alcohol are reacted in the presence of a hydrogenation catalyst and hydrogen, with addition/coexistence of a selected metal to introduce a substituent group on the amino group of the melamine derivative.
The N-substituted melamine derivatives obtained by the present reaction inhibit the association of multiple molecules by hydrogen bonds between the molecules that is inherent to melamine so that the products generally have improved solubility in water and/or various polar solvents as compared with the starting material melamine, and at the same time have improved compatibility with other organic compounds due to decreased melting points. These changes in physical properties further improve the reactivity with other reactive compounds considerably. Hence, said melamine derivative can be applied to those resins for which it has conventionally been difficult to use melamine, and at the same time exhibit very great modification effects.
An object of the present invention is to provide a method for modifying melamine derivatives that enable to easily produce N-substituted melamine derivatives that can be used widely as fine chemical intermediates such as various agricultural chemicals, medicines, dyes and paints, as various resin materials and as flame retardant materials.
In the first aspect, the present invention relates to a method for modifying melamine derivatives by introducing a substituent to melamine or an N-substituted melamine derivative, characterized by heating melamine or an N-substituted melamine derivative and an alcohol in the presence of a mixed catalyst comprising a hydrogenation catalyst and a dehydrogenation catalyst, and hydrogen to allow reaction.
In the second aspect, the present application relates to a method for modifying melamine derivatives by introducing a substituent to melamine or the N-substituted melamine derivative, characterized by heating melamine or an N-substituted melamine derivative and an alcohol in the presence of a hydrogenation catalyst and hydrogen with addition/coexistence of a selected metal to allow reaction.
Hereinafter, the first and second inventions will be described in more detail.
Melamine or N-substituted melamine derivatives, the starting materials of the present invention, are melamine derivatives represented by the general formula (I)
wherein at least one of groups R
1
, R
2
, R
3
, R
4
, R
5
and R
6
is a hydrogen atom, and other groups each independently are C
1-20
alkyl group (the alkyl may optionally be substituted by one or more substituents, which are different or the same, selected from the group consisting of halogen, C
1-6
alkoxy, C
2-6
dialkylamino, C
2-7
alkoxycarbonyl and phenyl.) or phenyl (the phenyl may optionally be substituted by one or more substituents, which are different or the same, selected from the group consisting of halogen, C
1-6
alkyl, C
1-6
alkoxy and C
1-6
haloalkyl.), or two groups on the same nitrogen ato
Kitabayashi Takashi
Kousaka Hiroyuki
Masahashi Kouichi
Nakajima Yasuyuki
Tanaka Norio
Balasubramanian Venkataraman
Nissan Chemical Industries Ltd.
Oliff & Berridg,e PLC
Shah Mukund J.
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