Abstract: Polytetrahydrofuran derivatives of the general formula ##STR1## where n is from 2 to 70, X is the bridge member --NH-- or --O-- and R.sup.1 and R.sup.4 are each hydrogen or various radicals.

Abstract: Aminopropanol derivatives of the formula: ##STR1## where R.sup.1 and R.sup.2 are identical or different and are each hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl or hydroxyalkyl, each of not more than 6 carbon atoms, alkoxyalkyl, alkylthioalkyl or dialkylaminoalkyl, each of not more than 9 carbon atoms in total, or phenylalkyl or phenoxyalkyl where the alkyl radical is of not more than 6 carbon atoms and the phenyl radical is unsubstituted or substituted by alkyl or alkoxy, each of not more than 3 carbon atoms, or R.sup.1 and R.sup.2, together with the nitrogen atom which links them, form a 5-membered to 7-membered saturated heterocyclic ring which can be substituted by one or two phenyl and/or hydroxyl radicals and can contain an oxygen or nitrogen atom, as a further heteroatom in the ring, and such an additional nitrogen atom can be substituted by alkyl of 1 to 3 carbon atoms or by phenyl, and -- .circle.

Abstract: A process for the preparation of N-substituted pyrrolidones by catalytic hydrogenation of maleic anhydride, maleic acid and/or fumaric acid in the presence of ammonia uses at least stoichiometric amounts of a primary alcohol or of an aldehyde and uses a catalyst which comprises cobalt and at least one of the elements manganese, copper, phosphorus, molybdenum and/or sodium.

Abstract: Hydroxybenzaldehydes of the formula (I) are prepared from a benzaldehyde of the formula (II) or its acetal, in which R.sup.1 in the R.sup.1 O-phenyl ether group is an alkyl, cycloalkyl, alkylcycloalkyl or alkylaryl radical, R.sup.2 is H or OH or is identical to R.sup.1 and one or more R.sup.1 O-phenyl ether groups are ortho, meta or para to the aldehyde function, by a process in which a benzaldehyde of the formula (II) or its acetal, in which R.sup.1 and R.sup.2 have the abovementioned meanings and one or more R.sup.1 O-phenyl ether groups occupy the abovementioned position with respect to the aldehyde function, is converted into a hydroxybenzaldehyde of the formula (I) in the presence of water over a zeolite as a heterogeneous catalyst. ##STR1## The catalysts used are, in particular, zeolites of the pentasil type.

Abstract: A pure D- or L-alanine enantiomer is prepared by reacting an optically active chloropropionic acid with ammonia in water or a water/alcohol mixture at from 50.degree. to 110.degree. C.

Abstract: Amino compounds of the formula ##STR1## where R.sup.1 is alkyl, A is alkylene or alkenylene, and Ar is aryl, and their acid addition salts, and fungicides containing these compounds.

Abstract: Pyrroles of the formula I ##STR1## are prepared by a process in which a dialkoxytetrahydrofuran of the formula II ##STR2## where R.sup.2 to R.sup.5 in the formulae (I) and (II) are identical or different and are each hydrogen, a straight-chain or branched alkyl or alkenyl radical of not more than 12 carbon atoms, a cycloalkyl or cycloalkenyl radical of 5 to 8 carbon atoms, an aryl, alkylaryl or aralkyl radical of 6 to 16 carbon atoms, and two non-adjacent radicals R.sup.6 to R.sup.9 are alkoxy and the other two radicals R.sup.6 to R.sup.9 are hydrogen, is reacted with ammonia or a primary amine H.sub.2 NR.sup.1, where R.sup.1 in formula (I) is hydrogen, alkyl, aryl, alkylaryl, aralkyl or cycloalkyl, in the presence of an acidic, solid, heterogeneous catalyst. Zeolites, for example those of the pentasil type or faujasite type, or phosphates, acidic oxides, phosphoric acid or boric acid on a carrier can be used as the solid heterogeneous catalysts.

Abstract: Aromatics are acylated by the Friedel-Crafts method by carrying out the acylation in the presence of metalalkyls or metalalkyl halides of metals or semimetals of main groups two to five and/or of metals of subgroups two or four of the Periodic Table.

Abstract: Alkyl-substituted aromatic ketones are prepared by reacting alkylbenzenes with carboxylic anhydrides in the presence of a Friedel-Crafts catalyst by performing the reaction in the presence of a tertiary amine or diamine.

Abstract: 4-methyl-4-phenyl-1-pentanals of the general formula I ##STR1## where R.sup.1 is hydrogen or C.sub.1 -C.sub.4 -alkyl and R.sup.2 is hydrogen or methyl, with the exception of 4-methyl-4-phenyl-1-pentanal, and the use of the methylphenylpentanals of the formula I for imparting fragrance properties to, or improving or modifying the fragrance properties of, perfumes and perfumed products, and the preparation of these compounds by hydroformylation of the corresponding 3-methyl-3-phenyl-1-butenes of the general formula II ##STR2## and, if required, subsequent reaction with formaldehyde and partial hydrogenation.

Abstract: Benzaldehyde dialkyl acetals of the formula ##STR1## where R is alkyl of 1 to 4 carbon atoms, are prepared by electrochemical oxidation of 3-tert-butyl-4-methoxytoluene in the presence of an alkanol of the formula ROH and are used as scents or scent intermediates.

Abstract: Substituted 4-methyl-4,7-dihydro-1,3-dioxepins of the general formula I ##STR1## where R.sup.1 is an alkyl of 1 to 12 carbon atoms which may furthermore contain oxygen in the form of an ether group, or a 5-membered to 8-membered ring which is unsubstituted or substituted by alkyl groups and/or an alkylene group, has up to 10 carbon atoms and may furthermore contain oxygen in the form of an ether group, and R.sup.2, R.sup.3 and R.sup.4 are each hydrogen or methyl, with the exception of the compound 2-tert-butyl-4,7-dihydro-4,7-dimethyl-1,3-dioxepin, the preparation of substituted 4-methyl-4,7-dihydro-1,3-dioxepins and their use as scents and aromas, and scent compositions containing these compounds.

Abstract: A process for the preparation of optically pure D- or L-lactic acid by fermentation of an aqueous nutrient medium, which contains nitrogen, vitamins, aminoacids, sugars and trace elements, by means of a microorganism, at pH 4-6, wherein the nutrient medium contains brewers' yeast as the source of nitrogen, vitamins, aminoacids and trace elements.

Abstract: Substituted 5-formyl-1,3-dioxepans of the general formula I ##STR1## where R.sup.1 is a straight-chain or branched alkyl radical of 1 to 10 carbon atoms which may furthermore contain oxygen in the form of an ether group, or a 5-membered to 8-membered ring which is unsubstituted or substituted by alkyl groups and/or an alkylene group, has up to 10 carbon atoms and may furthermore contain oxygen in the form of an ether group, R.sup.2 is hydrogen, or R.sup.1 and R.sup.2 together form an alkylene radical of 4 to 10 carbon atoms which is unsubstituted or substituted by alkyl or alkoxy and may furthermore contain oxygen in the form of an ether group, and R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each hydrogen or methyl, and the total number of carbon atoms is not more than 25, their preparation and their use as scents.

Abstract: Aliphatic aldehydes of the general formula I ##STR1## where R.sup.1 is hydrogen or methyl,R.sup.2 is a straight-chain or branched alkyl radical of 1 to 4 carbon atoms and the two radicals X are each hydrogen or together form a further C--C bond, in particular2,5,7,7-tetramethyloctanal,2,4,5,7,7-pentamethyloctanal,2-ethyl-5,7,7-trimethyloctanal and2,5,7,7-tetramethyl-2-octen-1-al, are used in scent compositions and are prepared by a process in which an aldehyde of the general formula II ##STR2## is condensed with an aldehyde of the general formula III ##STR3## in the presence of an aldol condensation catalyst to give the substituted octenal of the general formula I, and, if required, the latter is partially hydrogenated or reduced to give the ocorresponding octanal of the formula I.

Abstract: Cyclohexane-1,3-dione derivatives of the formula ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 have the meanings given in the description, are used for controlling undesirable plant growth.

Abstract: 2-Substituted 4,4,7,7-tetramethyl-1,3-dioxacycloheptanes of the general formula I ##STR1## where R.sup.1 is a straight-chain or branched alkyl of 1 to 10 carbon atoms which additionally may contain oxygen in the form of an ether group or is 5- to 8-membered cycloalkyl of up to 10 carbon atoms which may additionally contain oxygen in the form of an ether group, of which particularly interesting representatives are 2,4,4,7,7-pentamethyl-1,3-dioxacycloheptane, 2-tert.-butyl-4,4,7,7-tetramethyl-1,3-dioxacycloheptane and 2-isopropyl-4,4,7,7-tetramethyl-1,3-dioxacycloheptane, are prepared and used as scents.

Abstract: Esters of optically active 2-arylalkanoic acids I ##STR1## where Ar is an isocyclic or heterocyclic aryl radical and R.sup.1 and R.sup.2 are each C.sub.1 -C.sub.4 -alkyl, are prepared by subjecting an optically active ester II ##STR2## where X is Cl, Br or --O--SO.sub.2 --Y and Y is Cl or a hydrocarbon radical, to a Friedel-Crafts reaction with an aromatic compound ArH (III).

Abstract: Cyclohexane-1,3-dione derivatives of the formula ##STR1## where A is tetrahydropyran-4-yl, 3-methyltetrahydropyran-4-yl, 1,4-dioxanyl, 5,5-dimethyl-1,3-dioxan-2-yl, 2,5-dimethyl-1,4-dioxan-3-yl, 2,6-dimethyl-1,4-dioxan-3-yl, 2-methyl-1,3-dithiolan-2-yl, 2,6-dimethyltetrahydrothiopyran-3-yl, 2-methyl-1,3-dithian-2-yl or unsubstituted or substituted 1,3-dioxepan-5-yl, R.sup.1 is hydrogen or methoxycarbonyl, R.sup.2 is alkyl and R.sup.3 is alkyl, alkenyl, haloalkenyl or propargyl, are used for controlling undesirable plant growth of grass species, especially in broadleaved crops and monocotyledon crops which do not belong to the grass family.

Abstract: Benzaldehyde dialkyl acetals of the formula ##STR1## wherein R.sup.1 and R.sup.2 are each alkyl, are prepared by electrochemical oxidation of an alkyltoluene of the formula ##STR2## by a process in which the electrolyte used contains from 60 to 90% by weight of an alkanol of the formula R.sup.2 OH, from 8.5 to 40% by weight of the alkyltoluene and from 0.01 to 1.5% by weight of an HO.sub.3 S-containing acid.