Organic compounds -- part of the class 532-570 series – Organic compounds – Sulfur containing
Reexamination Certificate
2001-06-08
2003-04-29
Gerstl, Robert (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Sulfur containing
C560S024000, C560S157000, C564S393000
Reexamination Certificate
active
06555713
ABSTRACT:
TECHNICAL FIELD
The present invention relates to the inhibition of, decomposition of di-t-butyl dicarbonate. More specifically, it relates to the inhibition of decomposition of di-t-butyl dicarbonate in liquid form.
BACKGROUND ART
Di-t-butyl dicarbonate is an important compound as a protective agent for an amino group in the synthesis of pharmaceuticals and agricultural chemicals.
However, di-t-butyl dicarbonate is a thermally unstable compound and gradually decomposes when stored in liquid form. Therefore, when it is to be stored, it has been necessary to store it in a low-temperature storage at temperatures lower than its melting point so as to keep it in solid form.
However, since the melting point of di-t-butyl dicarbonate is 22 to 23° C., solid di-t-butyl dicarbonate melts partially in use, thereby making it very difficult to handle. Therefore, to avoid the difficulty in handling the solid di-t-butyl dicarbonate, the compound must be used in liquid form by keeping it at temperatures higher than its melting point at all times. However, when the compound is kept in liquid form for a long time, the decomposition as described above cannot be avoided.
Further, since it is complicated from an industrial point of view as well to melt the compound in solid form, those who use the compound on a large scale has desired to obtain the compound in liquid form. However, heretofore, such desire has been difficult to fulfill for maintaining the quality of the compound.
Therefore, a method for inhibiting the decomposition of di-t-butyl dicarbonate in liquid form has been desired.
DISCLOSURE OF THE INVENTION
The present inventors have made intensive studies to solve the above problems. As a result, they have found that the decomposition of di-t-butyl dicarbonate can be inhibited by adding a hydrocarbon compound and/or a chain ether compound to di-t-butyl dicarbonate and have therefore completed the present invention.
That is, firstly, the present invention relates to a mixed composition consisting essentially of (a) di-t-butyl dicarbonate and (b) at least one compound selected from the group consisting of a hydrocarbon compound and a chain ether compound.
Further, secondly, the present invention relates to the use of at least one compound selected from a group consisting of a hydrocarbon compound and a chain ether compound for inhibiting the decomposition of di-t-butyl dicarbonate.
Still further, thirdly, the present invention relates to the use of the mixed composition of the present invention for protecting the amino group of an amino group-containing compound by a t-butoxycarbonyl group.
PREFERRED EMBODIMENTS OF THE INVENTION
Preferred embodiments of the present invention will be described in detail hereinafter.
In the present invention, a compound used for inhibiting the decomposition of di-t-butyl dicarbonate (to be sometimes referred to as “decomposition inhibitor” hereinafter) is a hydrocarbon compound or a chain ether compound.
As the hydrocarbon compound in the present invention, a known compound which comprises carbon and hydrogen and which can be kept in liquid or solid form at room temperature and atmospheric pressure can be used without any limitation.
The hydrocarbon compound is preferably a saturated aliphatic hydrocarbon having 5 to 16 carbon atoms, an unsaturated aliphatic hydrocarbon having 5 to 16 carbon atoms or an aromatic hydrocarbon having 6 to 18 carbon atoms. Of these, a saturated aliphatic hydrocarbon having 5 to 9 carbon atoms, an unsaturated aliphatic hydrocarbon having 5 to 9 carbon atoms and an aromatic hydrocarbon having 6 to 7 carbon atoms are more preferable.
Illustrative examples of the hydrocarbon compound include saturated aliphatic hydrocarbons having 5 to 16 carbon atoms such as pentane, 2-methylbutane, hexane, 2-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, 2,2,3-trimethylpentane, octane, isooctane, nonane, 2,2,5-trimethylhexane, decane, undecane, dodecane, tridecane, tetradecane, hexadecane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, p-menthane and bicyclohexyl; unsaturated hydrocarbons having 5 to 16 carbon atoms such as 1-hexene, 1-pentene, 1-octene, 1-heptene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-hexadecene, cyclohexene, &agr;-pinene and dipentene; and aromatic hydrocarbons having 6 to 18 carbon atoms such as benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, cumene, mesitylene, naphthalene, tetralin, butyl benzene, p-cymene, cyclohexyl benzene, diethyl benzene, pentyl benzene, dipentyl benzene, dodecyl benzene, biphenyl and styrene.
Of these, saturated aliphatic hydrocarbons having 5 to 9 carbon atoms such as pentane, 2-methylbutane, hexane, 2-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, 2,2,3-trimethylpentane, octane, isooctane, 2,2,5-trimethylhexane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane and ethylcyclohexane; unsaturated aliphatic hydrocarbons having 5 to 9 carbon atoms such as 1-hexene, 1-pentene, 1-octene, 1-heptene and 1-nonene; and aromatic hydrocarbons having 6 or 7 carbon atoms such as benzene and toluene are suitably used in that their effect of inhibiting the decomposition is high.
As the chain ether compound in the present invention, a known compound in which two hydrocarbon groups are bonded to an oxygen atom and which can be kept in liquid or solid form at room temperature and atmospheric pressure can be used without any limitation. An example of the compound is an ether compound represented by the following formula (1):
R
1
—O—R
2
(1)
wherein R
1
and R
2
independently represent an alkyl group having 2 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms.
Of these, a dialkyl ether having 4 to 8 carbon atoms is preferable.
Illustrative examples of the chain ether compound include chain ether compounds having 4 to 12 carbon atoms such as diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, t-butyl methyl ether, di-t-butyl ether, dihexyl ether, ethyl vinyl ether and butyl vinyl ether.
Of these, dialkyl ether compounds having 4 to 8 carbon atoms such as diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, t-butyl methyl ether and di-t-butyl ether are suitably used in that their effect of inhibiting the decomposition is high.
All of these hydrocarbon compounds and chain ether compounds can be obtained easily as reagents and industrial raw materials.
These decomposition inhibitors may be used solely or in combination of two or more as required.
Although the decomposition inhibitor is not limited to a particular amount, it should be used in such an amount that ensures that the concentration of the decomposition inhibitor should be 0.1 to 95 wt %, preferably 1 to 80 wt %, based on the total amount of di-t-butyl dicarbonate and the decomposition inhibitor to obtain a satisfactory effect of inhibiting the decomposition. Therefore, the concentration of di-t-butyl dicarbonate is 99.9 to 5 wt %, preferably 99 to 20 wt %, based on the total amount of di-t-butyl dicarbonate and the decomposition inhibitor.
As a method of mixing the decomposition inhibitor and di-t-butyl dicarbonate, a conventional mixing method can be used without any limitation. However, it is preferable that they be mixed by stirring or the like to form a homogeneous mixture. In this case, they can be charged into a mixing container simultaneously or successively and then mixed.
As for the mixing temperature, when it is too high, di-t-butyl dicarbonate decomposes. It is generally 50° C. or lower, preferably 30° C. or lower.
To store the mixture, it is put in a closed container, an inert gas is introduced into the container, and the container is stored in a cool, dark place.
As for the storage temperature, when it is too high, a satisfactory effect of inhibiting the decomposition cannot be obtained, and di-t-butyl dicarbonate decomposes. It is generally 30° C. or lower, preferably 10° C. or lower.
A decomposition inhibitor obtained as a reagent or an industrial raw material may be
Hirano Naoki
Saijo Masako
Birch & Stewart Kolasch & Birch, LLP
Gerstl Robert
Tokuyama Corporation
LandOfFree
Protection of di-t-butyl dicarbonate against decomposition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Protection of di-t-butyl dicarbonate against decomposition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Protection of di-t-butyl dicarbonate against decomposition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3082317