The present disclosure provides a method for preparing 2-ethyl-4-fluoro-1-nitrobenzene, including: (1) nitrifying 3-fluoroacetophenone with a nitration reagent, to obtain 1-(5-fluoro-2-nitrophenyl)ethanone; (2) reducing 1-(5-fluoro-2-nitrophenyl)ethanone with a reducing agent, to obtain 4-fluoro-2-(1-hydroxyethyl)-1-nitrobenzene; (3) iodinating 4-fluoro-2-(1-hydroxyethyl)-1-nitrobenzene, to obtain 4-fluoro-2-(1-iodoethyl)-1-nitrobenzene; and (4) reducing 4-fluoro-2-(1-iodoethyl)-1-nitrobenzene with a reducing agent, to obtain 2-ethyl-4-fluoro-1-nitrobenzene.

The present disclosure provides a method for preparing 2-ethyl-4-fluoro-1-nitrobenzene, including: (1) nitrifying 3-fluoroacetophenone with a nitration reagent, to obtain 1-(5-fluoro-2-nitrophenyl)ethanone; (2) reducing 1-(5-fluoro-2-nitrophenyl)ethanone with a reducing agent, to obtain 4-fluoro-2-(1-hydroxyethyl)-1-nitrobenzene; (3) iodinating 4-fluoro-2-(1-hydroxyethyl)-1-nitrobenzene, to obtain 4-fluoro-2-(1-iodoethyl)-1-nitrobenzene; and (4) reducing 4-fluoro-2-(1-iodoethyl)-1-nitrobenzene with a reducing agent, to obtain 2-ethyl-4-fluoro-1-nitrobenzene.

The invention relates to monocarbonyl complexes of ruthenium and osmium with bi- and tridentate nitrogen and phosphine ligands. The invention relates to methods for preparing these complexes and the use of these complexes, isolated or prepared in situ, as catalysts for reduction reactions of ketones and aldehydes both via transfer hydrogenation or hydrogenation with hydrogen.

The invention relates to monocarbonyl complexes of ruthenium and osmium with bi- and tridentate nitrogen and phosphine ligands. The invention relates to methods for preparing these complexes and the use of these complexes, isolated or prepared in situ, as catalysts for reduction reactions of ketones and aldehydes both via transfer hydrogenation or hydrogenation with hydrogen.

The invention relates to monocarbonyl complexes of ruthenium and osmium with bi- and tridentate nitrogen and phosphine ligands. The invention relates to methods for preparing these complexes and the use of these complexes, isolated or prepared in situ, as catalysts for reduction reactions of ketones and aldehydes both via transfer hydrogenation or hydrogenation with hydrogen.

The invention relates to monocarbonyl complexes of ruthenium and osmium with bi- and tridentate nitrogen and phosphine ligands. The invention relates to methods for preparing these complexes and the use of these complexes, isolated or prepared in situ, as catalysts for reduction reactions of ketones and aldehydes both via transfer hydrogenation or hydrogenation with hydrogen.

Disclosed are a borohydride reduction stabilizing system and a method for reducing an ester to an alcohol. The borohydride reduction stabilizing system includes: a borohydride reducing agent and a stabilizing agent for stabilizing the borohydride reducing agent. The borohydride reducing agent is sodium borohydride or potassium borohydride. The stabilizing agent is an alkali metal salt of an alcohol. By adding the alkali metal salt of the alcohol, such as sodium alkoxide or potassium alkoxide, on the basis of an existing sodium/potassium borohydride reducing agent, the sodium/potassium borohydride reducing agent may be kept stable without being decomposed under the condition of increased temperature, so that on the one hand, the reducing activity is maintained in a relatively high state, and the condition of excessive use is reduced, and on the other hand, the generation of hydrogen is reduced, and the process risks are reduced.

Disclosed are a borohydride reduction stabilizing system and a method for reducing an ester to an alcohol. The borohydride reduction stabilizing system includes: a borohydride reducing agent and a stabilizing agent for stabilizing the borohydride reducing agent. The borohydride reducing agent is sodium borohydride or potassium borohydride. The stabilizing agent is an alkali metal salt of an alcohol. By adding the alkali metal salt of the alcohol, such as sodium alkoxide or potassium alkoxide, on the basis of an existing sodium/potassium borohydride reducing agent, the sodium/potassium borohydride reducing agent may be kept stable without being decomposed under the condition of increased temperature, so that on the one hand, the reducing activity is maintained in a relatively high state, and the condition of excessive use is reduced, and on the other hand, the generation of hydrogen is reduced, and the process risks are reduced.

The invention provides novel methods for preparing indolinobenzodiazepine dimer compounds and their synthetic precursors.

The invention provides novel methods for preparing indolinobenzodiazepine dimer compounds and their synthetic precursors.