The present invention relates to a process for synthesizing large scale a compound of formula (I), or pharmacuetically acceptable salt thereof, which is useful as the key intermediate for the synthesis of compounds for prophylaxis and treatment of a disease associated with the deposition of β-amyloid in the brain, in particular Alzheimer's disease, and other diseases such as cerebral amyloid angiopathy, hereditary cerebral hemorrhage with amyloidosis, Dutch-type (HCHWA-D), multi-infarct dementia, dementia pugilistica and Down syndrome.

##STR00001##

The present invention relates to a process for synthesizing large scale a compound of formula (I), or pharmacuetically acceptable salt thereof, which is useful as the key intermediate for the synthesis of compounds for prophylaxis and treatment of a disease associated with the deposition of β-amyloid in the brain, in particular Alzheimer's disease, and other diseases such as cerebral amyloid angiopathy, hereditary cerebral hemorrhage with amyloidosis, Dutch-type (HCHWA-D), multi-infarct dementia, dementia pugilistica and Down syndrome.

##STR00001##

A low sulfur diesel blockage inhibitor as shown in formula (I), a preparation method therefor, and use thereof are provided. In formula (I), x and y are each an integer between 0 and 4; m and n are each selected from H, a C1-C6 linear or branched alkyl group, or a C3-C6 cycloalkyl group. By using a vegetable oil as a raw material, a modified vegetable oil fatty acid is first obtained, and then a polar group of an unsaturated dialdehyde with a certain chain length is introduced into a molecular chain of the modified vegetable oil fatty acid.

##STR00001##

A low sulfur diesel blockage inhibitor as shown in formula (I), a preparation method therefor, and use thereof are provided. In formula (I), x and y are each an integer between 0 and 4; m and n are each selected from H, a C1-C6 linear or branched alkyl group, or a C3-C6 cycloalkyl group. By using a vegetable oil as a raw material, a modified vegetable oil fatty acid is first obtained, and then a polar group of an unsaturated dialdehyde with a certain chain length is introduced into a molecular chain of the modified vegetable oil fatty acid.

##STR00001##

Catalytic conversion of ketoacids is disclosed, including methods for increasing the molecular weight of ketoacids. An exemplary method includes providing in a reactor a feedstock having at least one ketoacid. The feedstock is then subjected to one or more C—C-coupling reaction(s) in the presence of a catalyst system having a first metal oxide and a second metal oxide.

Catalytic conversion of ketoacids is disclosed, including methods for increasing the molecular weight of ketoacids. An exemplary method includes providing in a reactor a feedstock having at least one ketoacid. The feedstock is then subjected to one or more C—C-coupling reaction(s) in the presence of a catalyst system having a first metal oxide and a second metal oxide.

A long-chain composition has at least one long-chain alkane selected from the group consisting of C9-18 linear or branched alkanes and at least one long-chain carboxylic acid selected from the group consisting of C9-18 linear or branched, saturated or unsaturated aliphatic monocarboxylic acids. The mass ratio of the long-chain alkane to the long-chain carboxylic acid ranges from 1:1 to 40:1. The long-chain composition has a higher fermentation degree or higher substrate utilization rate and the like, when used as a starting material in the production of long-chain dibasic acids via fermentation.

A long-chain composition has at least one long-chain alkane selected from the group consisting of C9-18 linear or branched alkanes and at least one long-chain carboxylic acid selected from the group consisting of C9-18 linear or branched, saturated or unsaturated aliphatic monocarboxylic acids. The mass ratio of the long-chain alkane to the long-chain carboxylic acid ranges from 1:1 to 40:1. The long-chain composition has a higher fermentation degree or higher substrate utilization rate and the like, when used as a starting material in the production of long-chain dibasic acids via fermentation.

The present disclosure relates to an isomerization method of a cyclohexane dicarboxylic acid (CHDA) and, more specifically, to a method for preparing a trans-cyclohexane dicarboxylic acid (t-CHDA) from a cis-cyclohexane dicarboxylic acid (c-CHDA) by means of catalytic isomerization.

Particularly, an embodiment of the present disclosure provides a method for preparing, in high efficiency and high yield and at a low cost, a CHDA having a high t-CHDA content from a CHDA mainly containing c-CHDA, by using an isomerization catalyst containing zirconia and having a BET specific surface area of 50 m.sup.2/g or more.

The present disclosure relates to an isomerization method of a cyclohexane dicarboxylic acid (CHDA) and, more specifically, to a method for preparing a trans-cyclohexane dicarboxylic acid (t-CHDA) from a cis-cyclohexane dicarboxylic acid (c-CHDA) by means of catalytic isomerization.

Particularly, an embodiment of the present disclosure provides a method for preparing, in high efficiency and high yield and at a low cost, a CHDA having a high t-CHDA content from a CHDA mainly containing c-CHDA, by using an isomerization catalyst containing zirconia and having a BET specific surface area of 50 m.sup.2/g or more.