Provided is a method of preparation of (1R, 3S)-3-amino-1-cyclopentanol, the method including: contacting N-acylhydroxyamine and cyclopentadiene for an asymmetric cycloaddition, to yield a first intermediate I; hydrogenating the first intermediate I to yield a second intermediate II; hydrolyzing, ammonolyzing, hydrazinolyzing, or alcoholyzing an amido bond of the second intermediate II to yield a third intermediate III; and hydrogenating the third intermediate III to yield (1R, 3S)-3-amino-1-cyclopentanol.

A process for the conversion of glycolaldehyde with an aminating agent in the presence of hy-5 drogen and of a catalyst, wherein the conversion is carried out in the gas phase.

A process for the conversion of glycolaldehyde with an aminating agent in the presence of hy-5 drogen and of a catalyst, wherein the conversion is carried out in the gas phase.

A method for at least partial deacetylation of a biopolymer comprising acetyl groups, including: a1) providing a biopolymer including acetyl groups; a2) reacting the biopolymer including acetyl groups with hydroxylamine (NH.sub.2OH) or a salt thereof at a temperature of 100° C. or less for 2-200 hours to form an at least partially deacetylated biopolymer; and a3) recovering the at least partially deacetylated biopolymer.

A method for at least partial deacetylation of a biopolymer comprising acetyl groups, including: a1) providing a biopolymer including acetyl groups; a2) reacting the biopolymer including acetyl groups with hydroxylamine (NH.sub.2OH) or a salt thereof at a temperature of 100° C. or less for 2-200 hours to form an at least partially deacetylated biopolymer; and a3) recovering the at least partially deacetylated biopolymer.

A method of preparing a 2,6 disubstituted anilines includes, reacting a 2-amino isophthalic acid diester with sufficient Grignard reagent R.sub.2CH.sub.2MgX to form the corresponding diol product, dehydrating the diol product to the corresponding dialkene; and hydrogenating the diol product to form the corresponding aniline. The 2,6 disubstituted anilines can be used to produce N-Heterocyclic Carbenes (NHCs). The NHCs can find application in various fields such as organic synthesis, catalysis and macromolecular chemistry. Palladium catalysts containing the NHCs are also described.

A method of preparing a 2,6 disubstituted anilines includes, reacting a 2-amino isophthalic acid diester with sufficient Grignard reagent R.sub.2CH.sub.2MgX to form the corresponding diol product, dehydrating the diol product to the corresponding dialkene; and hydrogenating the diol product to form the corresponding aniline. The 2,6 disubstituted anilines can be used to produce N-Heterocyclic Carbenes (NHCs). The NHCs can find application in various fields such as organic synthesis, catalysis and macromolecular chemistry. Palladium catalysts containing the NHCs are also described.

The present invention relates to a novel process for the preparation of Tapentadol and intermediate compound 2R,3R)-3-(-methoxyphenyl)-N,N,2-trimethylpentanamine (compound of formula IIa).

The present invention relates to a novel process for the preparation of Tapentadol and intermediate compound 2R,3R)-3-(-methoxyphenyl)-N,N,2-trimethylpentanamine (compound of formula IIa).

The invention relates to the field of pharmaceutical synthesis, in particular to the preparation method of hexahydrofuro-furanol derivative, intermediates thereof and preparation methods thereof. The preparation methods comprises the steps of halogenation reaction, acylation reaction, enzymatic reduction reaction, reaction with amine compounds, reduction ring closure reaction (A1, A2, B, Cp1, C.sub.L, Cf)

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wherein, R.sub.1, R.sub.2, R.sub.3 are hydrogen or hydroxy protecting groups; R.sub.4 and R.sub.5 are the same or different and are phenyl, alkyl or substituted phenyl. In the preparation process of hexahydrofuro-furanol derivatives, the chirality is constructed by enzymatic method, and the product can be prepared with very high optical purity by adopting such technical means. The preparation method can be used to prepare the key intermediate, (3R, 3aS, 6aR)-hexahydrofuro[2,3-b]-3-ol, of Darunavir, in commercial production, which is a very economical route suitable for industrial production.