Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system
Patent
1996-03-29
1998-04-14
Ford, John M.
Organic compounds -- part of the class 532-570 series
Organic compounds
Four or more ring nitrogens in the bicyclo ring system
544211, C07D25146
Patent
active
057393281
DESCRIPTION:
BRIEF SUMMARY
This is a 371 of PCT/EP84/03331, filed Oct. 10, 1994.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for preparing asymmetrically substituted triazines of the general formula I ##STR3## where R.sup.1 is hydrogen, methyl or ethyl, R.sup.2 and R.sup.3 independently of one another are a hydrocarbon radical having 1 to 6 C atoms, which can carry substituents which are inert under the reaction conditions, by reaction of a cyanoguanidine of the formula II ##STR4## with a carboxylic acid derivative in the presence of an alcohol of the formula III
2. Description of Related Art
Asymmetrically substituted triazines can be prepared in a great variety of ways, eg. starting from N-cyanoamides by reaction with Vilsmeier complexes (R. L. N. Harries, Aust. J. Chem. 34 (1981) 623), from N-cyanoimidate esters (DE-A 34 11 202; M. A. Perez, J. L. Soto, Heterocycles, 20 (1983) 463; K. R. Huffman, F. C. Schaefer, J. Org. Chem. 28 (1963) 1816) or from biguanidines (S. L. Shapiro et al, J. Org. Chem. 25 (1960) 379; U.S. Pat. No. 2,535,968). The reaction of guanylthiourea with dimethyl sulfate and carboxylic acid derivatives has also been published (H. Eilingsfeld, H. Scheuermann, Chem. Ber. 100 (1967) 1874; DE-A 16 70 147; EP-A 545 149) as well as the reaction of trichloroacetamidinoguanidines with derivatives of trifluoroacetic acid (DE-A 40 34 078). According to all these methods, no chelate complexes are passed through as intermediates.
Another possibility for preparing 6-trifluoromethyl-1,3,5-triazines according to a process known from Yakugaku Zasshi 95, (1975) 499-511 consists in converting N-cyanoguanidines into copper complexes of N-amidino-O-alkylisoureas, liberating the urea derivatives with hydrogen sulfide and then reacting them with trifluoroacetate esters according to the following reaction scheme: ##STR5## A variant of this process is known from DD-A-252 374, the acetate of copper being used instead of copper(II) chloride.
Stoichiometric amounts of Cu salts are necessary for this process; in the absence of Cu salts, mainly guanylurea is formed instead of the N-amidino-O-alkylisourea (Kyushu Kogyo Daigaku Kenkyu Hokoku No. 12, (1962) 69-78).
The reaction of N-amidino-O-alkylisourea hydrochloride with ethyl chloroacetate in ethanol/NaOC.sub.2 H.sub.5 leads to the corresponding chloromethyltriazine only in poor yields. The starting material has to be set free from the Cu complex beforehand.
The preparation of chelate complexes starting from cyanoguanidine using copper acetate or zinc chloride in methanol is described by R. I. Dutta and A. Syamal in Coord. Chem. Rev., Vol. 2, 1967, pp. 441-457. It is known from Chemistry of Heterocyclic Compounds, Vol. 25, 1989, pp. 547-550 to isolate zinc complexes of this type and then to react them with trifluoroacetic anhydride to give the triazine.
In a similar manner, zinc sulfate forms a chelate complex which after working up by boiling in water decomposes in a second reaction step to give the sulfate of amidino-O-methylisourea (U.S. Pat. No. 3,360,534, IN-A 167 500) and this can be reacted in a third reaction step with acetic anhydride (S. Lotz, G. Kiel, G. Gattow, Z. anorg. allg. Chem. 604 (1991) 53-62) or with methyl trifluoroacetate (T. Tsujikawa, Yakugaku Zasshi 95, loc. cit) to give the triazine in yields of 31 and 26% respectively.
The last-mentioned processes are always very laborious multistage processes which in the case of the esters lead to the desired triazines only in poor yields or in the case of the anhydrides inevitably include the production of stoichiometric amounts of carboxylic acid which can only be recycled to give the corresponding anhydrides very laboriously. As a rule, the toxicologically unacceptable, occasionally poorly filterable heavy metal complexes have to be isolated and then reacted with the anhydrides in an inert solvent, as reaction in alcoholic solution is prevented on account of the reaction of anhydrides with alcohols. In addition, the processes described are disadvantageous inasmuch as u
REFERENCES:
patent: 3360534 (1967-12-01), Odo
patent: 4886881 (1989-12-01), Chiang
Yakugaku Zashi 95, 499-511 (1975)--English translation.
Dutta et al., Coord. Chem. Rev., 1967, 441-457.
Chem. of Heterocyclic Compounds, Nov. 1989, 547-550, vol. 25, No. 5.
Mayer Horst
Schafer Bernd
BASF - Aktiengesellschaft
Ford John M.
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