Rhone-poulenc S.a.

Agence Nationale De Valorisation De La Recherche (anvar)

Centre National De La Recherche Scientifique

Roussel Uclaf

Marc Julia

Pierre F Chabardes

Albert Menet

Therese Cuvigny

Lucien Saussine

Retinal is prepared by condensing a C.sub.15 sulphide of formula: ##STR1## in which R.sub.1 denotes aryl, aralkyl, pyridyl, 2-thiazolyl, 2-benzothiazolyl, 2-benzimidazolyl or 2-benzoxazolyl, with a haloacetal of formula: ##STR2## in which X denotes a halogen atom and R denotes an alkyl radical containing 1 to 4 carbon atoms, to give a C.sub.20 sulphide acetal of formula: ##STR3## in which R.sub.1 and R are defined as above, hydrolysing the said sulphide acetal to give a C.sub.20 sulphide aldehyde of formula: ##STR4## in which R.sub.1 is defined as above, desulphurizing the said sulphide aldehyde to give retinal, and isolating the retinal obtained.

Process for preparing retinal

A novel process for the preparation of pent-4-enoic acids of the formula ##STR1## wherein X is selected from the group consisting of hydrogen, cyano and alkoxycarbonyl of 2 to 5 carbon atoms and Y is selected from the group consisting of hydrogen, cyano, alkoxycarbonyl 2 to 5 carbon atoms, acyl of an organic carboxylic acid of 2 to 7 carbon atoms, alkylsulfonyl of 1 to 4 carbon atoms and arylsulfonyl of 6 to 7 carbon atoms with the proviso that X and Y are not both hydrogen comprising reacting a compound of the formula ##STR2## wherein R is selected from the group consisting of acyloxy of an organic carboxylic acid of 1 to 7 carbon atoms, alkylsulfonyl of 1 to 4 carbon atoms and arylsulfonyl of 6 to 7 carbon atoms with an anion derivative of a compound of the formula ##STR3## wherein X.sub.1 and Y.sub.1 have the above definition for X and Y, respectively, except hydrogen in the presence of a palladium compound or nickel (o) complex and optionally a catalytic quantity of a ligand to obtain a compound of the formula ##STR4## wherein X.sub.1 and Y.sub.1 have the above definition and optionally subjecting the latter to a decarbalkoxylation when X.sub.1 or Y.sub.1 is alkoxycarbonyl or to a reduction when X.sub.1 is arylsulfonyl to obtain the corresponding compound of formula I.

Novel process

1,5-Dimethyl-hexa-1,5-dienylene compounds, and especially Vitamin A and derivatives thereof, are made by desuphonylating with a basic reagent a sulphone of the formula: ##STR1## in which the sulphonyl group --SO.sub.2 R replaces a hydrogen atom on carbon atom (a) or (b), R represents a phenyl or napthyl group, A is 2-(2,6,6-trimethylcyclohex-1-enyl)ethenyl, and Q is --CH.sub.2 OH or an ether or ester thereof, CHO, or an acetal group.

Process for preparing compounds having a 1,5-dimethyl-hexa-1,5-dienylene

Sulphones useful for preparing polyenes have the formula: ##STR1## where the sulphonyl group replaces a hydrogen atom on carbon atom (a) or (b), R represents alkyl, aralkyl or aryl, optionally substituted, A and Q represent an optionally substituted hydrocarbon of 5n+1 carbon atoms (n is 1-5), methyl, optionally substituted by halogen, sulphide or sulphone, CH.sub.2 OH (or an ether or ester thereof), CHO (optionally protected), COOH (or an acid chloride, ester or nitrile thereof), with the proviso that when A represents a 2-(2,6,6-trimethylcyclohex-1-enyl) ethenyl radical, Q cannot represent --COOH or an ester thereof.

Sulphones having a 1,5-dimethyl-hexa-1,5-dienylene group

The present invention relates to a process for the preparation of unsaturated sulphones. It relates to a process in which unsaturated sulphones are prepared by sulphonation of the corresponding diene compound in the presence of a palladium catalyst, the sulphonating agent being a sulphinic acid or a sulphinate in the presence of an acid. The sulphones obtained are synthesis intermediates, particularly in the preparation of vitamins A and E.

Process for the preparation of unsaturated sulphones

Sulphones with an alcohol group and their esters

Sulphones of the formula: ##STR1## in which R is a substituted or unsubstituted alkyl, alkylaryl, aralkyl, or aryl radical, A is a radical containing one or more isoprene units which is saturated, unsaturated, or of the conjugated or unconjugated polyene type, which is unsubstituted or substituted by one or more functional groups, halogen atoms or alkyl groups, and which may be cyclic when the number of isoprene units is at least 2, and Q is hydrogen or a cyclic or acyclic hydrocarbon radical which is saturated, unsaturated, or of the conjugated or unconjugated polyene type, and which is unsubstituted or substituted by one or more functional groups, halogen atoms or alkyl groups are useful intermediates in the production of terpene compounds such as .beta.-carotene and canthaxanthine.

Sulphones

Carotene compounds e.g. .beta.-carotene, are prepared by reacting a sulphone Ret--SO.sub.2 --R, in which Ret represents retinyl or substituted retinyl and R represents a hydrocarbon radical, in the presence of an alkaline reagent with an ester Ret-X, in which X represents an acid residue, and then desulphonating the product, for example with an alkaline reagent.

Alkenyl aryl sulfones

Olefinic sulfones of the general formula: ##STR1## wherein one of X and Y represents a hydrogen atom and the other represents an -SO.sub.2 -Ar radical in which Ar represents an aryl radical and n is an integer from 1 to 3, the &gt; CH-SO.sub.2 Ar group may be reduced to a methylene group to give Olefins which are known sexual attractants for flies.

Olefinic sulfones

Sulphones of formula QSO.sub.2 CH.sub.2 CY=CY.sub.1 CH.sub.2 CHRR.sub.1 wherein one of Y and Y.sub.1 is hydrogen the other methyl, R and R.sub.1 are CHO, COR.sub.2, COOH, COOR.sub.3, CONR.sub.5 R.sub.5, CN, SO.sub.2 R.sub.4, SO.sub.3 R.sub.5 and NO.sub.2, wherein R.sub.2 -R.sub.5 are alkyl or aryl and R.sub.5 can be hydrogen, and Q is alkyl, substituted alkyl, aryl, aralkyl or alkaryl or optionally substituted, optionally unsaturated terpene of 5n carbon atoms (n being 1-9), but excluding 2- or 3-methylbutadienyl and 2-butadienylmethyl, are intermediates for preparing terpenes.

Methyl-pentenyl sulphones

The invention relates to a process for the preparation of ethylenic compounds and to certain novel ethylenic compounds produced by the process. The process comprises the reaction of an appropriate carbonyl compound with a sulphone to obtain an alcohol sulphone which is then reduced to obtain the desired ethylenic compound.

Process for synthesizing ethylenic compounds

The invention relates to a process for the grafting a chain on to the 10-position carbon atom of a tricyclene skeleton, more particularly for producing 10-substituted stereospecific tricyclenes, especially cis-.alpha.-santalene and cis-.alpha.-santalol. The process involves the production of a sulphone of the tricyclene, the reaction of the sulphone with the halogenated derivative of the desired side chain and desulphonating the product.

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Paris, France

Marc Julia