Provided is a method for preparing a diol. In the method, a saccharide and hydrogen as raw materials are contacted with a catalyst in water to prepare the diol. The employed catalyst is a composite catalyst comprised of a main catalyst and a cocatalyst, wherein the main catalyst is a water-insoluble acid-resistant alloy; and the cocatalyst is a soluble tungstate and/or soluble tungsten compound. The method uses an acid-resistant, inexpensive and stable alloy needless of a support as a main catalyst, and can guarantee a high yield of the diol in the case where the production cost is relatively low.

Provided is a method for preparing a diol. In the method, a saccharide and hydrogen as raw materials are contacted with a catalyst in water to prepare the diol. The employed catalyst is a composite catalyst comprised of a main catalyst and a cocatalyst, wherein the main catalyst is a water-insoluble acid-resistant alloy; and the cocatalyst is a soluble tungstate and/or soluble tungsten compound. The method uses an acid-resistant, inexpensive and stable alloy needless of a support as a main catalyst, and can guarantee a high yield of the diol in the case where the production cost is relatively low.

The present invention discloses a triphenylsulfonium salt compound as shown in the general formula (I), wherein R.sub.1 represents an electron-withdrawing group and R.sub.2 represents an amplification group. Said compound shows significantly enhanced solubility and photosensitivity compared with unsubstituted triphenylsulfonium salts, and has significantly advantageous performance compared with prior art improved substitutes. ##STR00001##

The present invention relates to a process for preparing a 3-isopropenyl-6-heptenal compound of the following formula (2): wherein R.sup.1 represents a hydrogen atom or a methyl group, the process comprising: subjecting a 3-isopropenyl-6-heptenoate ester compound of the following formula (1): wherein R.sup.1 is as defined above, and R.sup.2 represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, to a reduction reaction with a reducing agent to form the 3-isopropenyl-6-heptenal compound (2). ##STR00001##

The present invention relates to a process for preparing a 3-isopropenyl-6-heptenal compound of the following formula (2): wherein R.sup.1 represents a hydrogen atom or a methyl group, the process comprising: subjecting a 3-isopropenyl-6-heptenoate ester compound of the following formula (1): wherein R.sup.1 is as defined above, and R.sup.2 represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, to a reduction reaction with a reducing agent to form the 3-isopropenyl-6-heptenal compound (2). ##STR00001##

The present invention discloses a novel method of preparing 8-methyldecanal, a flavor and fragrance material. Specifically, starting from cheap and readily available material 6-chloro-1-hexanol, first, the hydroxyl group was protected with dihydropyran catalyzed by para-toluene sulfonic acid to produce 6-chloro-hexyl tetrahydropyran ether. Then 6-chloro-hexyl tetrahydropyran ether reacted with magnesium turnings to form a Grignard reagent and reacted with 1-bromo-2-methyl-butane under the catalysis of cuprous bromide to give the intermediate 8-methyl-sunny tetrahydropyran ether. Without purification, crude 8-methyl-sunny tetrahydropyran ether was treated under acidic conditions to remove the protecting group to generate 8-methyl-1-decyl alcohol. Finally, 8-methyl decanal was obtained after oxidation with 2, 2, 6, 6-tetramethylpiperidinyloxy. The novel method of preparing 8-methyldecanal disclosed in the present invention utilizes common raw materials with low costs, the reaction conditions are mild, and yield is high. It is suitable for large-scale production.

Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.