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MXPA99005360A - Method for producing 2-chloro-5-aminomethylthiazole from 2-chloro-5-methylthiazole via 2-chloro-5-chloromethylthiazole - Google Patents

Method for producing 2-chloro-5-aminomethylthiazole from 2-chloro-5-methylthiazole via 2-chloro-5-chloromethylthiazole

Info

Publication number
MXPA99005360A
MXPA99005360A MXPA/A/1999/005360A MX9905360A MXPA99005360A MX PA99005360 A MXPA99005360 A MX PA99005360A MX 9905360 A MX9905360 A MX 9905360A MX PA99005360 A MXPA99005360 A MX PA99005360A
Authority
MX
Mexico
Prior art keywords
chloro
aminomethylthiazole
radical
methylthiazole
ammonia
Prior art date
Application number
MXPA/A/1999/005360A
Other languages
Spanish (es)
Inventor
Lantzsch Reinhard
Hupperts Achim
Stelzer Uwe
Original Assignee
Bayer Ag 51373 Leverkusen De
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bayer Ag 51373 Leverkusen De filed Critical Bayer Ag 51373 Leverkusen De
Publication of MXPA99005360A publication Critical patent/MXPA99005360A/en

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Abstract

The present invention relates to a method for producing 2-chloro-5-aminomethylthiazole characterized in that 2-chloro-5-methylthiazole is made to react in a first stage with a radical chlorinating agent in the presence of a radical former and halogenated in the presence of a diluent that is stable in respect to anti-radical halogenating agents so as to yield 40 to 70 wt.%. Ammonia or an aqueous ammonia solution is added to the reaction mixture arising therefrom in a second stage and the 2-chloro-5-aminomethylthiazole is isolated in the usual manner.

Description

PROCEDURE FOR THE OBTAINING OF 2-CHLORO-5-AMINOMETHYLSTAZOL FROM 2-CHLORO-5-METHYL-TEAZOL THROUGH 2-CHLORO-5-CHLOROMETHYLTYAZOLE.
FIELD OF THE INVENTION.
The present invention relates to a process for the preparation of 2-chloro-5-aminomethylthiazole.
DESCRIPTION OF THE PREVIOUS TECHNIQUE.
The preparation of 2-chloro-5-aminomethylthiazole by reaction of 2-chloro-5-chloromethylthiazole with hexamethylenetetraamine is known from JP-A 4 021 674. In this reaction, however, dissociation of the hexamethylenetetraamine adduct formed is required. in an intermediate manner and remove and eliminate the secondary products that are formed during the dissociation.
The reaction of 2-chloro-5-chloromethylthiazole with aqueous ammonia solution (EP-A 446) was also known. 913). Of course the yields obtained in this case Ref .: 30417 are unsatisfactory.
DETAILED DESCRIPTION OF THE INVENTION.
A process for obtaining 2-chloro-5-aminomethylthiazole has been found, characterized in that in a first step, 2-chloro-5-methyl-thiazole is halogen with a radical chlorinating agent in the presence of a radical former and in the presence of a stable diluent against the radical halogenating agents, up to a conversion of 40 to 70% by weight and then, in a second step, the reaction mixture formed is combined with ammonia or with aqueous ammonia solution and isolates 2-chloro-5-aminomethylthiazole in the usual way.
The reaction can be represented by means of the formula scheme: As the radical chlorinating agents, preference may be given to N-chlorosuccinimide, 1,3-dichloro-5,5-dimethylhydantoin and trichloroisocyanuric acid.
The chlorinating agents are used in an amount of 0.5 to 1.3 equivalents of chlorine in relation to the thiazole. The approximately equivalent amount of chlorinating agent is preferred.
Diazylperoxides and azobisalkylnitriles, preferably azobisisobutyronitrile (= ®Profor N), azobiscyclohexylcarbonitrile, peroxides, such as, for example, lauroyl peroxide and dibenzoyl peroxide, may be mentioned as radical formers. The radical former is used in an amount of 0.01 to 1 equivalent, based on the chlorinating agent. An amount of 0.001 to 0.1 equivalents is preferred.
Suitable diluents which are stable to radical halogenation are: halogenated aromatic or aliphatic hydrocarbons, such as, for example, chlorobenzene, carbon tetrachloride, 1,2-di-chloroethane, decachlorobutane and also nitrobenzene or acetonitrile.
The reaction is carried out at an elevated temperature, preferably from room temperature to 150 ° C, particularly preferably at the boiling point of the diluent.
The reaction was carried out at normal pressure. However, it is also possible to work at elevated pressure of 1 to 10 bar.
The halogenation reaction is carried out until a yield in 2-chloro-5-chloromethylthiazole of 40 to 70% by weight, preferably 50 to 60% by weight, is reached. The reaction is then interrupted and the second stage of the reaction is started It was surprising that the halogenation of 2-chloro-5-methylthiazole occurred in the side chain without problems. In this way, a specific halogenation of the side chains could not be achieved with elemental chlorine or sulfuryl chloride. It was also surprising that the desired product could then be reacted without further purification. Thus it was known from the publication J. Am. Chem. Soc. 67, page 400 (1945) that, for example, 4-chloromethyl-2-methylthiazole is rapidly transformed into a resin. Similar reactions of transformation to resin and therefore coalescence and yield reductions of the desired 5-chloromethylthiazole derivative were also expected.
The development of the halogenation is controlled by means of assay by continuous gas chromatography of the reaction mixture. Once the desired yield has been reached in 2-chloro-5-chloromethylthiazole, the reaction mixture is freed from the solvent by distillation. The raw product obtained in this way is combined, without further purification, with ammonia, if appropriate in the presence of an inert solvent such as, for example, ether. Particularly preferred is the reaction with 65% NH3 (residue H20) at temperatures of 20 to 150 ° C and at high pressure of 2 to 100 bar. The molar ratio 2-chloro-5-chloromethylthiazole: NÍÍ5 amounts to 1: 10-60. The reaction time is between 0.5 and 6 hours.
The crude product can also be combined with concentrated aqueous ammonia solution. It is also possible to combine the reaction mixture from the halogenation, without prior elimination of the solvent, with ammonia or with ammonia solution.
The reaction with ammonia is carried out at temperatures of -40 ° C to 150 ° C. It can be operated at normal pressure as well as at high pressure. If working with liquid ammonia, the reaction will preferably be carried out in the autoclave at the vapor pressure of the ammonia.
After completion of the reaction, excess ammonia is removed, for example by distillation or by neutralization with an aqueous acid, for example hydrochloric acid.
The excess solvent is removed by distillation and the mixture formed, consisting of 2-chloro-5-amino-methylthiazole, is removed in the usual manner, for example by chromatography, distillation or removal of the amine by salt formation.
Example 1 Combine 2 g (0.015 mol) of 2-chloro-5-methylthiazole in 15 ml of carbon tetrachloride, with 2.4 g (0.019 moles) of N-chlorosuccinimide and 200 mg of azobisisobutyronitrile (AiBN) and heated for 6 hours under reflux. After cooling, it is combined with 50 ml of CH2C12, filtered, washed twice with water. After drying and removal of the solvent in vacuo, a yellow colored liquid is obtained, which is mixed with solid product. The conversion is, according to gaseous chromatography, of 50.0%, the gold compounds in the nucleus and polychlorinated compounds are present in a concentration of < 2 %.
Example 2 At room temperature for 1.5 hours, 1.5 g (0.011 mol) of 2-chloro-5-methylthiazole and 10 ml of carbon tetrachloride are heated with 1.7 g of 1,3-dichloro-5,5-dimethylhydantoin and 150 mg of carbon tetrachloride. AiBN. After analogous processing a crude product is obtained, which is constituted, in 48.5%, by 2-chloro-5-chloromethylthiazl.
Example 3 The crude mixture obtained in example 1 is reacted in an autoclave with 10 ml of liquid NH3 and 50 ml of tere. -amil-ethyl ether. It is allowed to reach room temperature and is stirred for a further 16 hours at room temperature additionally. After evaporation of the solvent and excess ammonia, 50 ml of 5% HCl are added, the mixture is extracted three times with CH 2 Cl 2, the aqueous phase is adjusted to pH 7 with concentrated NaOH and then extracted again. The extraction is adjusted to pH 11-12 with concentrated NaOH and the product is obtained by re-extraction. 1.18 g of 5-aminomethyl-2-chlorothiazole are isolated with a content of 95.3% according to gas chromatography.
Example 4 The crude mixture, obtained in example 2, is reacted in an autoclave with 30 ml of 65% NH3 at 70 ° C and at a pressure of 30 bar for 1.5 hours. The mixture was refrigerated and decompressed. After degassing in a vacuum, the pH is adjusted to 7 with aqueous HCl (5%) and with 10 ml of H20. After working-up, as described in example 3, 0.74 g of the desired product are isolated.
It is noted that in relation to this date, the best method known to the applicant, to carry out the aforementioned invention, is that which is clear from the present description of the invention.
Having described the invention as above, property is claimed as contained in the following:

Claims (1)

1. Process for obtaining 2-chloro-5-aminomethylthiazole, characterized in that, in a first step, 2-chloro-5-methylthiazole is halogen with a radical chlorinating agent in the presence of a radical former and in the presence of a stable diluent against the radical halogenating agents up to a conversion of 40 to 70% by weight and then, in a second step, the reaction mixture obtained, if necessary after prior elimination of the diluent, is combined with ammonia or aqueous solution of ammonia, if appropriate in a diluent and 2-chloro-5-aminomethylthiazole is isolated in the usual manner.
MXPA/A/1999/005360A 1996-12-20 1999-06-09 Method for producing 2-chloro-5-aminomethylthiazole from 2-chloro-5-methylthiazole via 2-chloro-5-chloromethylthiazole MXPA99005360A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19653586.7 1996-12-20

Publications (1)

Publication Number Publication Date
MXPA99005360A true MXPA99005360A (en) 2000-02-02

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