摘要:
A method of improving a strength property of a sheet-formed fibrous material formed from an aqueous slurry of cellulose fiber, comprising coating at least one face of the material with a coating formulation comprising a or consisting of polysaccharide containing at least two carboxylic groups and low molecular weight organic mono-, di- or poly-carboxylic acid in an aqueous carrier, keeping the coated face at a temperature of 50 °C or more for a time sufficient to obtain the desired improvement including drying of the material.
摘要:
A new catalytic asymmetric two-step or one-pot method for the preparation of the C-13 side-chain of paclitaxel (Taxol) and derivatives of the general formula (I) in the form of an acid, salt or ester, in which R represents an aryl group or alkyl group, R 1 represents an aryl group or alkyl group, Y represents O, H or alkyl, and X 1 represent -CH 2 -Ph, alkyl, aryl, SiR 3 (where the silyl group is a common protective group) or other suitable protective group.
摘要:
A process for the preparation of oxygen-, thio- and nitrogen-ring containing compounds comprising reacting a compound selected from the compounds of formula (I): or the compounds of formula (II): in which R 1 , R 2 , R 3 , R 4 = F, Br, C1, CN, NO 2 , COOH, COOR, alkyl, aromatic, CF 3 , OMe, OH, NR 2 , NRH, NH 2 , OR, CH 2 X, CHX 2 ; X = C1, F, Br and heteroatom; A = O, S, NH; R 5 = Me, Et, alkyl; with an α,β-unsaturated aldehyde or ketone in the presence of an amino compound as catalysts.
摘要翻译:一种制备含氧,硫代和氮环的化合物的方法,包括使选自式(I)的化合物或式(II)的化合物:其中R 1, R 2,R 3,R 4,F,Br,C 1,CN,NO 2, COOH,COOR,烷基,芳族,CF 3,OMe,OH,NR 2,NRH,NH 2,OR,CH 2 X,CHX 2; X = C1,F,Br和杂原子; A = O,S,NH; R 5 = Me,Et,烷基; 与α,β-不饱和醛或酮在氨基化合物作为催化剂存在下反应。
摘要:
The present disclosure relates to the environmentally preparation of nanocellulose and derivatives thereof. The invention further relates to the preparation of cellulose derivatives.
摘要:
The present invention relates generally to an eco-friendly methodology for the conversion of alcohols and aldehydes to amines and amides using an integrated enzyme cascade system with metal-and organocatalysis. More specifically, the present invention relates to synthesis of capsaicinoids starting from vanillin alcohol and using a combination of an enzyme cascade system and catalysts. Furthermore, the method also relates to synthesis of capsaicinoids derivatives starting from vanillin alcohol derivatives and using a combination of an enzyme cascade system and catalysts.
摘要:
This invention concerns the first environmentally benign heterogeneous modification of polysaccharide-based material in native solid state by thiol-ene "click chemistry". The direct reaction of a thiol with an un-activated double or triple bond by thiol-ene and thiol-enyne click modification is thermally or photochemically catalyzed and is completely metal-free and allows for a highly modular approach to modifications of fibers and fiber-based materials.
摘要:
The present invention presents catalytic systems for aldol condensation reactions, comprising the step of reacting at least one aldehyde or one ketone starting material in the presence of an inorganic ammonium salt, or an aqueous or organic solution prepared from such salt. The efficiency of the catalytic system of the present invention is comparable to those of the classical strong acid and strong base catalysts.
摘要:
A process for the preparation of for the preparation of β-amino aldehydes and derivatives thereof, in particular β-amino acids and Υ -amino alcohols, by reacting carbamate-protected imines and unmodified aldehydes in the presence of an amino compound as catalysts. The catalyst is preferably selected from amino acids, (S)-proline, peptides and derivatives thereof, chiral pyrrolidines, protected diarylprolinol derivatives and acyclic and cyclic amines.
摘要:
A process for the preparation of for the preparation of 5-hydroxyisoxazolidines, 5- isoxazo lidinones, β-amino acids, β-amino aldehydes and derivatives thereof, by reacting hydroxyl amines or hydroxyl carbamates with an α,β-unsaturated aldehyde or ketone in the presence of an amino compound as catalysts. The catalyst is preferably selected from amino acids, peptides and derivatives thereof, chiral pyrrolidines, protected diarylprolinol derivatives and acyclic and cyclic amines.
摘要:
This invention concerns the first mild and efficient synthesis of primary amines and amides from aldehydes or ketones using a heterogeneous metal catalystand amine donor. The initial heterogeneous metal- catalyzed reaction between the carbonyl and the amine donor components is followed up with the addition of a suitable acylating agent component in one-pot. Hence, the present invention provides a novel catalytic one-pot three-component synthesis of amides. Moreover, the integration of enzyme catalysis allows for eco-friendly one-pot co-catalytic synthesis ofamides from aldehyde and ketone substrates, respectively. The process can be applied to the co-catalytic one-pot three-component synthesis of capsaicin and its analogues from vanillin or vanillyl alcohol. It can also be applied for asymmetric synthesis. In the present invention, a novel co-catalytic reductive amination/dynamic kinetic resolution (dkr) relay sequence for the asymmetric synthesis of optically active amides from ketones is disclosed. Moreover, implementation of a catalytic reductive amination/kinetic resolution (kr) relay sequence produces the corresponding optically active amide product and optical active primary amine product with the opposite stereochemistry from the starting ketones.