GB824175A - Reactions involving grignard reagents - Google Patents

Abstract

A process for the preparation of an alcohol, an organic acid, an ester, a ketone, a thio ketone or an organic thio acid comprises reacting with a chlorocarbonic ester, a diester of carbonic acid, carbon dioxide, carbon disulphide or carbon oxysulphide an organo-magnesium chloride complex of the formula R(MgCl)x.nQ and, where necessary, hydrolysing the reaction mixture, R being a substituted or unsubstituted aryl or arylene group, a substituted or unsubstituted vinylic group or a substituted or unsubstituted heterocyclic radical which exhibits aromatic or pseudo aromatic characteristics and which includes in its heterocyclic ring an oxygen, sulphur or tertiary nitrogen atom and is bound to magnesium through a carbon atom of the aromatic or pseudo aromatic ring and R containing no functional group which is reactive under the conditions for the formation of the complex, Q being a molecule of a substituted or unsubstituted heterocyclic ether having 5 or 6 atoms in the ring, of which atoms only one is oxygen, the other ring atoms being carbon with the exception that a substituted nitrogen atom may replace the carbon atom in the 4position when the ring has 6 atoms, the ring containing not more than one double bond and at least one carbon atom in the ring adjacent the oxygen atom being free of any substituents, said ether containing no substituent which reacts with an organomagnesium chloride complex or with the other components or products of the reaction mixture, x being 1 or 2 and n being a small whole number of the order of 1 to 3. Cyclic ethers specified include tetrahydrofuran, tetrahydropyran. 2-methyltetrahydrofuran, 2-ethoxytetrahydropyran, tetrahydrofurfuryl ethyl ether, dihydropyran and N-methyl morpholine which may contain as substituents alkyl, aryl, alkoxy and aryloxy groups. Representative of the aryl radicals in the aryl magnesium chloride complexes specified are phenyl, any of the hydrogen atoms of which may be replaced by chlorine, alkyl, aryl, alkoxy or aryloxy radicals which optionally may be substituted with alkenyl, aralkyl, thienyl, thenyl and furyl radicals, allyloxy and dialkylamino radicals, two or more adjacent hydrocarbon substituents optionally being linked to form a cyclic saturated or condensed aromatic ring. The aryl radicals may be polynuclear, e.g. as in anthracyl, polychlorobiphenyl and acenaphthalenyl. Additional substituents mentioned include fluorine and alkylidenedioxy radicals. Representative of the arylene radicals in the arylene di-magnesium chloride complexes specified are those derived from benzene, diphenyl, anthracene and phenanthrene which may bear substituents specified above as aryl substituents. Representative of the heterocyclic radicals in the heterocyclic magnesium chloride complexes specified are thiophenyl, benzothiophenyl and dibenzothiophenyl, wherein nuclear hydrogen may be replaced by chlorine or condensed rings or additional substituents specified above as aryl substituents, pyridyl, quinonyl, acridyl, furyl, N-substituted pyrryl, indolyl, benzofuryl, dibenzofuryl, imidazolyl, benzoxazolyl, pyrimidyl, triazinyl, and pyridazinyl. Representative of vinylic groups in the vinylic magnesium chloride complexes specified are those in which any of the hydrogen atoms of the vinyl group are replaced by aliphatic or aromatic hydrocarbon groups or by two substituents forming a ring, e.g. as in cyclohexenyl. Specific products of the process mentioned include benzoic acid, p-toluic acid, the corresponding chloro acids and carboxylic acid derivatives of various polynuclear hydrocarbons, e.g. chrysene and acenaphthene, acrylic acid and substituted acrylic acids, e.g. isobutene-1-oic and p-methoxy styrene-a -carboxylic acid, terephthalic acid, polychlorinated benzoic acids, benzophenones, symmetrical ketones derived from various polynuclear hydrocarbons, Michler's ketone, ethyl 2-thienylcarboxylate, a -pyridyl dithionic acid, bis-2quinonyl ketone, 6-quinonyl-8-quinonyl ketone, ethyl 2 - benzoxazolyl carboxylate, ethyl 2 - benzothiazolyl carboxylate, chloropyrimidinylcarboxylic acid, ethyl 6-chloro-2-methoxyacrid-9-yl carboxylate, chloropyrimidinyl carboxylic acid, dithio furoic acid, a polythiophenylene ketone, ethyl 5-chlorothiophenoate and dithioacrylic acid. Chlorocarbonic esters specified for use in the process include alkyl, aryl, alkenyl, aralkyl and alkaryl chlorocarbonates. Carbonates specified include alkyl, aryl, alkenyl, aralkyl and alkaryl diesters of carbonic acid. Organomagnesium chloride complexes, the preparations of which are described, include tetrahydrofuran complexes with phenyl-, vinyl-, m- and p - chlorophenyl-, tolyl-, xenyl-, terphenyl-, naphthyl-, anthracyl-, phenanthryl-, xylyl-, phenylnaphthyl-, anisyl-, phenethyl-, pyrenyl-, cadalenyl-, perylenyl-, acenaphthyl-, chrysenyl-, picenyl-, chlortolyl-, thienyl-, a pyridyl-, 2-quinonyl-, 6- and 8-quinonyl-, 2benzoxazolyl-, 2 - benzothiazolyl-, 2 - methyl - benzothiazolyl-, 6 - chloro - 2 - methoxy - acrid9-yl-, chloropyrimidyl-, and 2-chloro-5-thiophenyl magnesium chlorides and with organomagnesium chlorides derived from chlorobenzenes containing 3-6 chlorine atoms, pdichlorobenzene and 2,5-dichlorothiophene. The preparation of phenyl magnesium chloride complexes in the presence of tetrahydropyran, 2methyltetrahydrofuran, 2 - ethoxymethyltetrahydrofuran and 2-ethoxytetrahydropyran is mentioned. Specifications 776,993, 777,158 and 779,100 are referred to.