A process for the preparation of a polyunsaturated thiol comprising: (1) reacting a polyunsaturated alcohol in the presence of a compound of formula R.sub.2SO.sub.2Hal wherein R.sub.2 is a C.sub.1-20 hydrocarbyl group, such an C.sub.1-10 alkyl group, to form a polyunsaturated sulphonyl ester; (2) converting the polyunsaturated sulphonyl ester to a polyunsaturated thioester by reacting with an anion of formula .sup.SC(O)R.sub.4 wherein R.sub.4 is a C.sub.1-20 hydrocarbyl group; (3) converting the polyunsaturated thioester to form a polyunsaturated thiol optionally in the presence of an antioxidant, e.g. using a metal carbonate. (4) reacting said polyunsaturated thiol with a compound (LG)R.sup.3COX wherein X is an electron withdrawing A group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2 forming (I) where X is an electron withdrawing group and LG is a leaving group; optionally in the presence of an antioxidant, so as to form a polyunsaturated ketone compound.

##STR00001##

A process for the preparation of a polyunsaturated thiol comprising: (1) reacting a polyunsaturated alcohol in the presence of a compound of formula R.sub.2SO.sub.2Hal wherein R.sub.2 is a C.sub.1-20 hydrocarbyl group, such an C.sub.1-10 alkyl group, to form a polyunsaturated sulphonyl ester; (2) converting the polyunsaturated sulphonyl ester to a polyunsaturated thioester by reacting with an anion of formula .sup.SC(O)R.sub.4 wherein R.sub.4 is a C.sub.1-20 hydrocarbyl group; (3) converting the polyunsaturated thioester to form a polyunsaturated thiol optionally in the presence of an antioxidant, e.g. using a metal carbonate. (4) reacting said polyunsaturated thiol with a compound (LG)R.sup.3COX wherein X is an electron withdrawing A group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2 forming (I) where X is an electron withdrawing group and LG is a leaving group; optionally in the presence of an antioxidant, so as to form a polyunsaturated ketone compound.

##STR00001##

A process for the preparation of a polyunsaturated thiol comprising: (1) reacting a polyunsaturated alcohol in the presence of a compound of formula R.sub.2SO.sub.2Hal wherein R.sub.2 is a C.sub.1-20 hydrocarbyl group, such an C.sub.1-10 alkyl group, to form a polyunsaturated sulphonyl ester; (2) converting the polyunsaturated sulphonyl ester to a polyunsaturated thioester by reacting with an anion of formula .sup.SC(O)R.sub.4 wherein R.sub.4 is a C.sub.1-20 hydrocarbyl group; (3) converting the polyunsaturated thioester to form a polyunsaturated thiol optionally in the presence of an antioxidant, e.g. using a metal carbonate. (4) reacting said polyunsaturated thiol with a compound (LG)R.sup.3COX wherein X is an electron withdrawing A group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2 forming (I) where X is an electron withdrawing group and LG is a leaving group; optionally in the presence of an antioxidant, so as to form a polyunsaturated ketone compound.

##STR00001##

An embodiment relates to an aromatic polythiol compound for optical materials, and the aromatic polythiol compound according to the embodiment contains a phenyl group and a large number of sulfur atoms in its polythiol structure so that a polymerizable composition and an optical material obtained therefrom have excellent optical properties such as high refractive index and low specific gravity, as well as excellent mechanical properties such as low cure shrinkage; thus, they can be advantageously used for producing various plastic optical lenses such as eyeglass lenses and camera lenses.

The present invention relates to an industrial process for the preparation of (5S,10S)-10-benzyl-16-methyl-11,14,18-trioxo-15,17,19-trioxa-2,7,8-trithia-12-azahenicosan-5-aminium (E)-3-carboxyacrylate salt of following formula (I): wherein X is fumarate. This process comprises the following successive key steps: a kinetic resolution, formation of disulfide compound, peptide coupling, and anion exchange reaction to obtain the desired product of formula (I). ##STR00001##

The present invention relates to an industrial process for the preparation of (5S,10S)-10-benzyl-16-methyl-11,14,18-trioxo-15,17,19-trioxa-2,7,8-trithia-12-azahenicosan-5-aminium (E)-3-carboxyacrylate salt of following formula (I): wherein X is fumarate. This process comprises the following successive key steps: a kinetic resolution, formation of disulfide compound, peptide coupling, and anion exchange reaction to obtain the desired product of formula (I). ##STR00001##

The present invention relates to an industrial process for the preparation of (5S,10S)-10-benzyl-16-methyl-11,14,18-trioxo-15,17,19-trioxa-2,7,8-trithia-12-azahenicosan-5-aminium (E)-3-carboxyacrylate salt of following formula (I): wherein X is fumarate. This process comprises the following successive key steps: a kinetic resolution, formation of disulfide compound, peptide coupling, and anion exchange reaction to obtain the desired product of formula (I). ##STR00001##

The invention relates to a catalyst comprising an active component based on molybdenum and on potassium and a support based on hydroxyapatite, and also to a process for preparing said catalyst and a process for producing methyl mercaptan in a catalytic process by reaction of carbon monoxide, sulphur and/or hydrogen sulphide and hydrogen, comprising the use of said catalyst.

The invention relates to a catalyst comprising an active component based on molybdenum and on potassium and a support based on hydroxyapatite, and also to a process for preparing said catalyst and a process for producing methyl mercaptan in a catalytic process by reaction of carbon monoxide, sulphur and/or hydrogen sulphide and hydrogen, comprising the use of said catalyst.

The invention relates to a catalyst comprising an active component based on molybdenum and on potassium and a support based on hydroxyapatite, and also to a process for preparing said catalyst and a process for producing methyl mercaptan in a catalytic process by reaction of carbon monoxide, sulphur and/or hydrogen sulphide and hydrogen, comprising the use of said catalyst.