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.2—SO.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 group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2— forming

##STR00001## 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.

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.2—SO.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 group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2— forming

##STR00001## 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.

The present application relates to compounds of formulae (I)-(VII) as defined herein, compositions containing these compounds, methods of their use, and methods of making. The compounds have nematacide activity.

The present invention relates to a process for purifying acrolein. The process includes the steps of a) splitting a liquid feed stream containing acrolein into at least a first liquid stream and a second liquid stream, b) introducing the first liquid stream with a temperature T1 into a distillation column at a point between the top and the bottom of the distillation column, c) introducing the second liquid stream with a temperature T2 into the distillation column at the top of the distillation column, d) withdrawing an overhead vapor stream enriched in acrolein from the distillation column, and e) withdrawing a bottom stream depleted in acrolein. The temperature T2 of the second liquid stream in step c) is lower than the temperature T1 of the first liquid stream in step b).

The present invention relates to a process for purifying acrolein. The process includes the steps of a) splitting a liquid feed stream containing acrolein into at least a first liquid stream and a second liquid stream, b) introducing the first liquid stream with a temperature T1 into a distillation column at a point between the top and the bottom of the distillation column, c) introducing the second liquid stream with a temperature T2 into the distillation column at the top of the distillation column, d) withdrawing an overhead vapor stream enriched in acrolein from the distillation column, and e) withdrawing a bottom stream depleted in acrolein. The temperature T2 of the second liquid stream in step c) is lower than the temperature T1 of the first liquid stream in step b).

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 group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2 forming ##STR00001## 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.

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 group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2 forming ##STR00001## 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.

The invention relates to the manufacture of certain polyunsaturated compounds employing a particular application of the Mitsonobu reaction in the presence of at least one anti-oxidant. We have found a method of making a pharmaceutically-acceptable polyunsaturated ester or thioester compound directly, which can ultimately be converted to the advantageous ketone compounds, in which unwanted oxidation and cis/trans isomerization are substantially reduced or eliminated using particular Mitsonobu chemistry.