Abstract: The invention relates to enantiomerically enriched malonic acid monoesters &agr;-monosubstituted by a tertiary hydrocarbon radical, or their salts, of the general formula I: in which R1, R3, R4 and R5 are identical or different hydrocarbon radicals, and wherein any two of the radicals R3, R4 and R5 may alternatively be present as a carbocyclic ring together with the quaternary carbon atom which they substitute, and M is hydrogen, one equivalent of a metal or an optionally substituted ammonium ion. The invention further relates to a process for the preparation of the enantiomerically enriched &agr;-monosubstituted malonic acid monoesters, or their salts, by enzymatic partial hydrolysis of the corresponding diesters.

Abstract: A process for preparing amino derivatives of C—H-acid compounds of the general formula I where R is an alkyl group, a cycloaliphatic radical, an aryl radical, an alkylaryl radical or an aralkyl radical, and X1 and X2 are identical or different electron-withdrawing groups, by reacting compounds of the general formula II with nitrous acid, where the nitrosation is carried out in the presence of from 1 to 10 mol of a carboxylic anhydride, and the reaction product is subjected to catalytic hydrogenation, where appropriate after removing the salts derived from the reaction. Compounds of the general formula I are useful intermediates for compounds which can be used in the pharmaceutical and agricultural sectors.

Abstract: Process for the preparation of amino acid derivatives of the general formula I where R1-R4 are as defined herein, from the corresponding malonic acid monoester amides of the general formula II  by Hofmann degradation using a hypohalite in an aqueously basic medium, which comprises carrying out the reaction in the presence of an alcohol or amine and using the hypohalite in amounts of from 1.0 to 1.5 equivalents and the base in amounts of from 0.8 to 4.0 equivalents per mole of starting material II.

Abstract: 2-Hydroxybenzonitrile is prepared by passing 2-hydroxybenzamide in the gas phase over a heterogeneous catalyst thereby effecting dehydration of the 2-hydroxybenzamide to produce 2-hydroxybenzonitrile.

Abstract: The invention relates to a process for the preparation of methoxyacetic acid esters in which a chloroacetic acid ester is reacted with an alkali metal methoxide to give the methoxyacetic acid ester.

Abstract: Cyclopropylamine is prepared from butyrolactone by a process comprising:(a) reacting butyrolactone with hydrogen chloride, thereby yielding chlorobutyric acid, (b) esterifying said chlorobutyric acid with a primary or secondary alcohol having 4-8 carbon atoms, (c) cyclizing the ester with an alkali metal alcoholate of a primary alcohol having 1-3 carbon atoms to give a mixture of cyclopropanecarboxylic acid esters, (d) converting the cyclopropanecarboxylic acid ester mixture into cyclopropanecarboxylic acid amide by reacting the ester mixture with ammonia, and (e) reacting said cyclopropanecarboxylic acid amide with hypohalite ion in a basic medium, thereby forming cyclopropylamine.

Abstract: Aminoacetic acid esters of formula I in which R.sup.1, R.sup.2 and R.sup.3 are identical or different hydrocarbon radicals, or any two of these radicals form a carbon ring with the carbon atom to which they are attached and R.sup.4 is hydrogen or an alkyl radical having 1-4 carbon atoms, are prepared by reacting an .alpha.-substituted malonic acid monoamide ester of formula II ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 have the meanings above, by the Hofmann degradation reaction, with a hypohalite in an amount of up to 1.5 equivalents in an aqueous-basic medium containing base in an amount of 0.8-1.5 equivalents per mol. of starting malonic acid monoamide ester II.

Abstract: A process for preparing high-purity cyclopropyl methyl ketone from compositions which contain cyclopropyl methyl ketone, 4,5-dihydro-2-methylfuran, addition products of 4,5-dihydro-2-methylfuran by a continuous rectification process in which at least a portion of the composition to be purified is introduced into a rectification apparatus via a side feed located above the bottom portion of the apparatus.

Abstract: Cyclopropyl alkyl ketones are separated from 3-acyltetrahydrofuran-2-ones by adding an alcohol, water or a water/alcohol mixture to a reaction product containing C.sub.1-4 -alkyl cyclopropyl ketone and 4,5-dihydro-2-alkylfuran by-product and an acid catalyst and reacting the by-product with the added alcohol, water of water/alcohol mixture before, during or after distilling said reaction product; and effectively separating C.sub.1 -.sub.4 -alkyl cyclopropyl ketone from reaction by-products.In the preparation of cyclopropyl alkyl ketones from 3-acyltetrahydrofuran-2-ones very reactive 4,5-dihydro-2-alkylfurans are also produced. By reacting such compounds with nucleophilic compounds, such as alcohols or water, before, during or after distillation of the reaction products, it is possible reliably to separate off the 4,5-dihydro-2-alkylfurans as high-boiling addition compounds.

Abstract: A process for the preparation of aminoacetic acids or aminoacetonitriles with a tertiary hydrocarbon radical in the .alpha.-position in which monoamide derivatives of malonic acid are subjected to a Hofmann rearrangement.

Abstract: A process for preparing hydroxymethylcyclopropane, in which formylcyclopropane is hydrogenated over copper chromite, zinc chromite and/or copper/zinc catalysts. The process may be batchwise or continuous.

Abstract: A process for the preparation of cyclopropanamine by Hofmann degradation of cyclopropanecarboxamide, comprising the following steps:(1) suspending cyclopropanecarboxamide, either (A) in 1.1 to 4 mol of sodium hydroxide, in solution whose concentration is 10 to 50%, per mol of amide, or (B) in a sparing amount of water,(2) adding 1 to 1.5 mol of hypochlorite, per mol of amide, from a 5 to 15% strength hypochlorite solution at a temperature of 0.degree. to 20.degree. C.,(3) adding 1.1 to 4 mol of sodium hydroxide, in solution whose concentration is 10 to 50%, per mol of amide, in the case where a suspension has been formed according to step (1)(B),(4) reacting the amide, hypochlorite, and sodium hydroxide for 10 to 60 minutes to form a homogeneous reaction mixture,(5) continuously passing the homogeneous reaction mixture through a tubular reactor at a temperature of 45.degree. to 260.degree. C.

Abstract: In a process for the preparation of cyclopropanecarboxamide by amidating cyclopropanecarboxylic esters with ammonia in alcoholic solution at from 60.degree. to 200.degree. C., the reaction being catalyzed by an alcoholate of a monohydric alcohol, high yields are achieved even in the absence of a hydrocarbon solvent when a cyclopropanecarboxylic ester of the formula ##STR1## in which R is C.sub.1 - to C.sub.3 -alkyl or cyclopropyl, is employed.

Abstract: The present invention relates to a novel process for preparing 1-aminocyclopropanecarboxylic acid hydrochloride (ACC.multidot.HCl) of the formula ##STR1## ACC.multidot.HCl is prepared from a cyclopropane-1,1-dicarboxylic acid diester via an 1-aminocarbonylcyclopropanecarboxylic acid ester intermediate and an alkali metal salt or alkaline earth metal salt of 1-aminocarbonylcyclopropanecarboxylic acid. The process represents a simplification and gives improved product yields.