Bayer Aktiengesellschaft

Mobay Chemical Corporation

Walter Merz

Karlfried Dickore

Hans Kratzer

Hans Dieter Engels

Christoph Mannheims

Reinhard Lantzsch

Udo Kraatz

Klaus Jelich

Hans Lindel

Martin Littmann

Gunter Schummer

Donovan Norman Smith, Jr

Dieter Nachtsheim

Johann Dahm

Method for producing optically active 1-phenylethylamines

The present invention relates to a process for the preparation of 5-substituted 2-chloropyridines of the formula (I) ##STR1## by reaction of acetenamides of the formula (II) ##STR2## with Vilsmeier reagent, which is prepared by reaction of dialkylformamides of the formula (III) ##STR3## with a chlorinating agent, the excess of which is removed from the reaction mixture by distillation or by addition of dialkylformamide after completion of the reaction of the Vilsmeier reagent with the acetenamide of the formula (II), wherein in the formulae (I)-(III):

Process for the preparation of 5-substituted 2-chloropyridines

Dichloropinacolone is produced by introducing into pinacolone twice the molar amount of chlorine, the exothermic reaction mass being cooled initially to maintain the temperature below about 50.degree. C. until about 60 to 80% of the chlorine has been introduced, and then heating the reaction mass to a temperature above 50.degree. C. during introducing of the remainder of the chlorine, thereby to produce dichloropinacolone, and terminating chlorine introduction when the dichloropinacolone content of the reaction mass is at least about 97%. The molten product is added to an aqueous solution of an alkali maintained at a temperature of at least about 50.degree. C., the alkali being present in more than three times the molar amount of the dichloropinacolone. To the resulting solution of a salt of 3,3-dimethyl-2-hydroxy-butyric acid, brought to a pH of about 9 to 12, there is added approximately the stoichiometric amount of potassium permanganate. Solid MnO.sub.2 precipitates out and is separated from the substantially pure dissolved salt of 3,3-dimethyl-2-oxo-butyric acid. The produce is a known compound suited for further syntheses.

Production of 3,3-dimethyl-2-oxo-butyric acid salt

Dichloropinacolone is produced by introducing into pinacolone twice the molar amount of chlorine, the exothermic reaction mass being cooled initially to maintain the temperature below about 50.degree. C. until about 60 to 80% of the chlorine has been introduced, and then heating the reaction mass to a temperature above 50.degree. C. during introducing of the remainder of the chlorine, thereby to produce dichloropinacolone, and terminating chlorine introduction when the dichloropinacolone content of the reaction mass is at least about 97%. The molten product is added to an aqueous solution of an alkali maintained at a temperature of at least about 50.degree. C., the alkali being present in more than three times the molar amount of the dichloropinacolone. To the resulting solution of a salt of 3,3-dimethyl-2-hydroxy-butyric acid, brought to a pH of about 9 to 12, there is added approximately the stoichiometric amount of potassium permanganate. Solid MnO.sub.2 precipitates out and is separated from the substantially pure dissolved salt of 3,3-dimethyl-2-oxo-butyric acid. The product is a known compound suited for further syntheses.

6-Tert.-butyl-3-mercapto-4-amino-1,2,4-triazin-(4H)-one is prepared by reacting pinacolone with a sulfur chloride at 0.degree. to 80.degree. C., optionally reacting the mixture with an aqueous amine solution, hydrolyzing the resulting product with an alkali metal hydroxide, heating the resulting mixture from 2 to 10 hours at 80.degree. to 150.degree. C., liberating a 3,3-dimethyl-2-oxo-butyric acid by acidifying with a mineral acid and reacting an aqueous solution of said 3,3-dimethyl-2-oxo-butyric acid with thiocarbohydrazide to yield the desired product.

Process for the preparation of

6-Tert.-butyl-3-mercapto-4-amino-1,2,4-triazin-5(4H)-one is prepared by reacting pinacolone with a sulfur chloride at 0.degree. to 80.degree. C, optionally reacting the mixture with an aqueous amine solution, hydrolyzing the resulting product with an alkali metal hydroxide, heating the resulting mixture from 2 to 10 hours at 80.degree. to 150.degree. C, liberating a 3,3-dimethyl-2-oxo-butyric acid by acidifying with a mineral acid and reacting an aqueous solution of said 3,3-dimethyl-2-oxo-butyric acid with thiocarbohydrazide to yield the desired product.

Process for the preparation of alkali metal salts of

A process for the treatment of waste water obtained in the condensation of thiocarbohydrazide and an aqueous solution of an .alpha.-keto carboxylic acid such as, e.g., 3,3-dimethyl-2-oxo-butyric acid, which comprises mixing said waste water with a water-immiscible ketone, preferably selected from the group consisting of methyl isobutyl ketone, cyclohexanone and pinacolone, said ketone being employed in an amount sufficient to form two phases, separating said two phases, and discharging as waste the aqueous phase. Advantageously the pH of the waste water is no higher than about 6 and its temperature is 20.degree. to 50.degree. C. The organic phase comprises the ketone containing dissolved therein an adduct of the ketone with thiocarbohydrazide and/or similar amino materials originally present in waste water. The excess of the ketone may be recovered from the organic phase by distillation, or the organic phase may be treated with alkali to effect hydrolysis of such adducts, the ketone separated and recycled and the amino materials recovered.

Treatment of waste water from the preparation of 6-substituted

The invention provides a novel synthesis for pinacolone comprising reacting 2-methyl-but-2-ene and/or 2-methyl-but-1-ene with an aqueous inorganic acid, adding formaldehyde gradually at a temperature between 50.degree. and 200.degree. C at a rate of 0.5 - 1.5 moles of formaldehyde per mole of butene compound, allowing the mixture to react further, and separating the pinacolone by distillation.

Process for the preparation of pinacolone

Dichloropinacolone is produced by introducing into pinacolone twice the molar amount of chlorine, the exothermic reaction mass being cooled initially to maintain the temperature below about 50.degree. C until about 60 to 80% of the chlorine has been introduced, and then heating the reaction mass to a temperature above 50.degree. C during introducing of the remainder of the chlorine, thereby to produce dichloropinacolone, and terminating chlorine introduction when the dichloropinacolone content of the reaction mass is at least about 97%. The molten product is added to an aqueous solution of an alkali maintained at a temperature of at least about 50.degree. C, the alkali being present in more than three times the molar amount of the dichloropinacolone. To the resulting solution of a salt of 3,3-dimethyl-2-hydroxy-butyric acid, brought to a pH of about 9 to 12, there is added approximately the stoichiometric amount of potassium permanganate. Solid MnO.sub.2 precipitates out and is separated from the substantially pure dissolved salt of 3,3-dimethyl-2-oxo-butyric acid. The product is a known compound suited for further syntheses.

In the methylation of 4-amino-6-t.-butyl-3-mercapto-1,2,4-triazin-5-one to produce 4-amino-6-t.-butyl-3-methylmercapto-1,2,4-triazine-5-one using methyl bromide, the reaction is run in the absence of air whereby product coloration is avoided. Desirably considerable agitation is employed along with recycle and especially with an emulsifying agent which markedly speeds up the reaction. Measures such as operating under a slight vacuum and recycle of unused methyl bromide and mother liquor are employed to improve the yield and to avoid the problems of discharging the bromides to the environment.

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Leverkusen, Germany

Walter Merz