Dynamit Nobel Aktiengesellschaft

Dynamit Nobel Aktiengesellshaft

Hans-Georg Schmidt

Wilhelm Vogt

Gerhard Daum

Disclosed is a process for preparing cis-trans isomer mixtures of 2,2-dimethyl-3(.beta.,.beta.-dichlorovinyl)-cyclopropane-1-carboxylic acid esters, having a high cis/trans isomer ratio, wherein a 4,4-dimethyl-5-halogen-6-alkoxytetrahydro-pyrone or a 3,3-dimethyl-4-halogen-5-oxo-pentanic acid ester is reacted with dichlorophosphonic acid esters in the presence of alkali alcoholates or alkali hydrides or lithium alkyls. Also disclosed are novel starting tetrahydropyrone compounds usable in the above process, and a process for preparation of the novel compounds which includes reacting .beta.,.beta.-dimethyl-.gamma.,.delta.-dihalogen-.delta.-valerolactones with alkali alcoholates at reaction temperatures between -10.degree. and +50.degree. C.

Process for the preparation of vinylcyclopropanecarboxylic acid

There are disclosed and claimed substituted cyclic lactones and process for preparation thereof. In particular, there are disclosed substituted cyclic lactones having alkyl substituents on the ring, especially such lactones having substituents on the ring of which two on the same carbon atom. Additionally, the invention herein disclosed and claimed relates to a process for the preparation of lactones by heating a six-membered hydroxy substituted lactone in the presence of a catalyst.

Process for preparing unsaturated six-membered lactones

Resorcinols of the structure of p-orsellinic acid ester are obtained from pyrones of the formula ##STR1## by the action of no more than catalytic amounts of bases.

Method of preparing p-orsellinic acid esters

There are disclosed substituted lactones of the formula ##STR1## wherein A stands for --CH--CH.sub.2 X (X being Cl, Br or OH), --CHY--CHY-- (Y being Cl or Br), or ##STR2## and R.sup.1, R.sup.2 and R.sup.3 are the same or different radicals from the group of hydrogen and C.sub.1 to C.sub.10 alkyls, at least one of the radicals R.sup.2, R.sup.2 and R.sup.3 being such an alkyl radical, and process for making the same.

3H-Furanones

There are disclosed substituted lactones of the formula ##STR1## wherein A stands for --CH--CH.sub.2 X (X being Cl, Br or OH), --CHY--CHY--(Y being Cl or Br), or ##STR2## and R.sup.1, R.sup.2 and R.sup.3 are the same or different radicals from the group of hydrogen and C.sub.1 to C.sub.10 alkyls, at least one of the radicals R.sup.1, R.sup.2 and R.sup.3 being such an alkyl radical, and process for making the same.

Substituted pyran-2-ones

3-alkyl-6-methyl-.beta.-resorcylic acid esters of the Formula ##STR1## wherein R.sup.1 and R.sup.2 represent identical or different alkyl groups of 1 to 10 carbon atoms, are prepared by the reaction of .alpha.-pyrones of the formula ##STR2## wherein R.sup.1 and R.sup.2 have the above meaning, with a base.

Method of preparing 3-alkyl-6-methyl-.beta.-resorcylic acid esters

There are disclosed substituted lactones of the formula ##STR1## wherein A stands for --CH--CH.sub.2 X (X being Cl, Br or OH), --CHY--CHY-- (Y being Cl or Br), or ##STR2## and R.sup.1, R.sup.2 and R.sup.3 are the same or different radicals from the group of hydrogen and C.sub.1 to C.sub.10 alkyls, at least one of the radicals R.sup.1, R.sup.2 and R.sup.3 being such an alkyl radical, and process for making the same.

Substituted lactones and processes for their preparation

A method of preparing certain dihalogen vinyl cyclopropane carboxylic acid esters of the formula ##STR1## wherein R is an alkyl moiety and X is chlorine or bromine by exposing a dihalogen vinyl dihydrofuran of the formula ##STR2## to light, e.g., ultraviolet light. Also disclosed is a method for preparing such 2,4,4-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans by reaction of a .beta.-alkoxycrotonic acid ester or 3,3-bisalkoxybutyric acid ester with a 1,1,1-trihalogen-4-methyl-3- or -4-pentene-2-ol in the presence of an acid catalyst. Also disclosed is a method of converting such 2,4,4-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof uran by thermal rearrangement into 2,5,5-trimethyl-3-carbalkoxy-4-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans. Such 2,4,4- and 2,5,5-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans are new.

2,5,5-Trimethyl-3-carbalkoxy-4(.beta.,.beta.-di

A method of preparing certain dihalogen vinyl cyclopropane carboxylic acid esters of the formula ##STR1## wherein R is an alkyl moiety and X is chlorine or bromine by exposing a dihalogen vinyl dihydrofuran of the formula ##STR2## to light, e.g., ultraviolet light. Also disclosed is a method for preparing such 2,4,4-trimethyl-3-carbalkoxy-5-(.beta..beta.-dihalogenvinyl)-4,5-dihydrofu rans by reaction of a .beta.-alkoxycrotonic acid ester or 3,3-bisalkoxybutyric acid ester with a 1,1,1-trihalogen-4-methyl-3-or -4-pentene-2-ol in the presence of an acid catalyst. Also disclosed is a method of converting such 2,4,4-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof uran by thermal rearrangement into 2,5,5-trimethyl-3-carbalkoxy-4-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans. Such 2,4,4- and 2,5,5-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans are new.

Method of preparing dihalogen vinyl cyclopropanecarboxylic acid esters

A method of preparing certain dihalogen vinyl cyclopropane carboxylic acid esters of the formula ##STR1## wherein R is an alkyl moiety and X is chlorine or bromine by exposing a dihalogen vinyl dihydrofuran of the formula ##STR2## to light, e.g., ultraviolet light. Also disclosed is a method for preparing such 2,4,4-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans by reaction of a .beta.-alkoxycrotonic acid ester or 3,3-bisalkoxybutyric acid ester with a 1,1,1-trihalogen-4-methyl-3- or -4-pentene-2-ol in the presence of an acid catalyst. Also disclosed is a method of converting such 2,4,4-trimethyl-3-carbalkoxy-5-(.beta., .beta.-dihalogenvinyl)-4,5-dihydrofuran by thermal rearrangement into 2,5,5-trimethyl-3-carbalkoxy-4-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans. Such 2,4,4- and 2,5,5-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans are new.

An improvement in the process for preparing an orthoacetic acid alkyl ester of the formula ##STR1## wherein R is a saturated, branched or un-branched, alkyl moiety of 1 to 8 carbon atoms by: (a) contacting acetonitrile with an anhydrous alkanol having 1 to 8 carbon atoms and dry hydrogen chloride in the presence of an organic solvent to prepare the corresponding imidoester hydrochloride; (b) thereafter contacting said imidoester hydrochloride in the acid-free state with an alkanol having 1 to 8 carbon atoms; and (c) removing by-product ammonium chloride from the resultant reaction mixture and distilling the reaction mixture to recover orthoacetic acid alkyl ester, the improvement residing in (d) employing as the organic solvent an inert solvent having a dielectric constant measured at 25.degree. C. of 2.6 or less; and (e) contacting said imidoester hydrochloride in step (b) with an alkali metal or alkaline earth metal alcoholate before contacting the same with said alkanol. Also disclosed is a process in which steps (a) and (b) are performed coterminously without isolation or recovery of the intermediate imidoester hydrochloride.

Method of preparing orthoacetic acid alkyl esters

A method of preparing certain dihalogen vinyl cyclopropane carboxylic acid esters of the formula ##STR1## wherein R is an alkyl moiety and X is chlorine or bromine by exposing a dihalogen vinyl dihydrofuran of the formula to light, e.g., ultraviolet light. Also disclosed is a method for preparing such 2,4,4-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogen-vinyl)-4,5-dihydro furans by reaction of a .beta.-alkoxycrotonic acid ester or 3,3-bisalkoxybutyric acid ester with a 1,1,1-trihalogen-4-methyl-3- or -4-pentene-2-ol in the presence of an acid catalyst. Also disclosed is a method of converting such 2,4,4-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof uran by thermal rearrangement into 2,5,5-trimethyl-3-carbalkoxy-4-(.beta.,.beta.-dihalogen-vinyl)-4,5-dihydro furans. Such 2,4,4- and 2,5,5-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans are new.

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Niederkassel, Germany

Hans-Georg Schmidt