The invention discloses a method for preparation of alkylated, fluoro alkylated, chloro alkylated and fluorochloro alkylated compounds by a heterogeneous Co-catalysed alkylation or fluoro, chloro and fluorochloro alkylation with alkyl halides, fluoro alkyl halides, chloro alkyl halides or fluorochloro alkyl halides respectively.

Disclosed are an anti-ice nucleation activator comprising a purine base or a purine base-containing polymer, and an antifreeze liquid comprising the anti-ice nucleation activator and water; a method for improving the anti-ice nucleation activity of a biological material, the method comprising bringing the anti-ice nucleation activator into contact with the biological material; and a method for preserving a biological material, the method comprising bringing the anti-ice nucleation activator into contact with a biological material.

Disclosed are an anti-ice nucleation activator comprising a purine base or a purine base-containing polymer, and an antifreeze liquid comprising the anti-ice nucleation activator and water; a method for improving the anti-ice nucleation activity of a biological material, the method comprising bringing the anti-ice nucleation activator into contact with the biological material; and a method for preserving a biological material, the method comprising bringing the anti-ice nucleation activator into contact with a biological material.

Disclosed are a series of hydroxyl purine compounds and the use thereof as PDE2 or TNF inhibitors, in particular, the compounds as shown in formula (I), or tautomers or pharmaceutically acceptable salts thereof. ##STR00001##

Disclosed are a series of hydroxyl purine compounds and the use thereof as PDE2 or TNF inhibitors, in particular, the compounds as shown in formula (I), or tautomers or pharmaceutically acceptable salts thereof. ##STR00001##

Disclosed are a series of hydroxyl purine compounds and the use thereof as PDE2 or TNF? inhibitors, in particular, the compounds as shown in formula (I), or tautomers thereof or pharmaceutically acceptable salts thereof. ##STR00001##

Disclosed are a series of hydroxyl purine compounds and the use thereof as PDE2 or TNF? inhibitors, in particular, the compounds as shown in formula (I), or tautomers thereof or pharmaceutically acceptable salts thereof. ##STR00001##

Disclosed are a series of hydroxyl purine compounds and the use thereof as PDE2 or TNF inhibitors, in particular, the compounds as shown in formula (I), or tautomers or pharmaceutically acceptable salts thereof.

##STR00001##

Disclosed are a series of hydroxyl purine compounds and the use thereof as PDE2 or TNF inhibitors, in particular, the compounds as shown in formula (I), or tautomers or pharmaceutically acceptable salts thereof.

##STR00001##

Disclosed are a series of hydroxyl purine compounds and the use thereof as PDE2 or TNF? inhibitors, in particular, the compounds as shown in formula (I), or tautomers thereof or pharmaceutically acceptable salts thereof.

##STR00001##