34 results about "Tert-Butyllithium" patented technology

The invention discloses a method for synthetising 2-bromine-N-methyl benzenesulfonyl pyrrole, relates to organic synthetic chemistry, and belongs to the field of medicines and chemical engineering. The method is characterized by comprising the following steps: firstly, a benzenesulfonyl reaction is conducted on pyrrole nitrogen to generate a stable intermediate compound; then, tert-butyllithium is allowed to highly selectively be subjected to lithiation reaction with ortho-position hydrogen of N-methyl benzenesulfonyl pyrrole; finally, the product is allowed to react with BrCN to obtain the target compound. The method has the benefits that the yield of the target compound is high, the total yield of the two steps of reactions reaches more than 50%, the purity is high, the reactions are easy to operate, the performance is high, and the industrial production is easy to realize.

The invention provides a method for preparing 2,4,5- trifluoro-3-methyl benzoic acid. The method is characterized in that 2,4,5-trifluorobenzoic acid reacts with mixed alkali under the condition of an organic solvent so as to obtain metal salt, of which the carboxylic group and the C3 site are substituted; mixed alkali comprises one of n-butyllithium or tert-butyllithium or lithium isopropoxide, one of potassium tert-butoxide or sodium methylate or potassium methoxide and one of 2,2,6,6-tetramethyl-piperidine or diisopropylamine or tetramethyl ethylenediamine or 2-hydrosulfuryl benzothiazole in a mixing manner, and organic solvent is alcohol ether solvent; metal salt reacts with methylating agents, and a substitution reaction is performed at the benzene ring C3 site so as to obtain 2,4,5- trifluoro-3-methyl benzoic acid; and the reaction temperature ranges from subzero 80 to 20 DEG C. The method has the advantages of high reaction temperature and low cost, and is easy for industrialized production.

The invention discloses a preparation method of a tert-butyllithium solution, which comprises the following steps: (1) in an inert gas protective atmosphere, adding sodium-lithium alloy into an inert solvent, heating while stirring to disperse the sodium-lithium alloy, cooling, and removing the inert solvent to obtain a sodium-lithium alloy dispersion; and (2) in an inert gas protective atmosphere, adding pentane into the sodium-lithium alloy dispersion obtained in the step (1), dropwisely adding a chlorinated n-butane-chlorinated tert-butyl alkane mixed solution at 30-38 DEG C while stirring to carry out reaction, and after the reaction is complete, treating to obtain the tert-butyllithium solution. By adding the catalytic amount of chlorinated n-butane into chlorinated tert-butyl alkane, the reaction for preparing the tert-butyllithium can be initiated and carried out smoothly, thereby implementing industrialized-scale production of the tert-butyllithium.

The invention discloses a rosuvastatin intermediate (R)-tert butyl dimethyl siloxy-glutaric acid monoester preparation method, which belongs to the field of medicine. The method is as follows: compound (S)-4-halogen-3-hydroxy butyric acid ethyl ester is taken as a raw material for ester exchange to obtain other (S)-4-halogen-3-hydroxy butyric ester, (S)-4-halogen-3-tert butyl dimethyl siloxy benzyl butyrate is obtained by protection of the (S)-4-halogen-3-hydroxy butyric ester, and by condensation of the (S)-4-halogen-3-tert butyl dimethyl siloxy benzyl butyrate and chloroformate in the presence of magnesium, tert butyl lithium and n-butyl lithium, (R)-tert butyl dimethyl siloxy-glutaric acid ester benzyl ester is obtained, and the (R)-tert butyl dimethyl siloxy-glutaric acid monoester is obtained by catalytic hydrogenation deprotection. Compared with the original process, the raw material of the process is chiral, natural, needs no resolution and induction and no enzyme hydrolysis to produce the chiral center, so that the product chirality is better. Compared with the original process, enzymes are already-industrialized enzymes, the raw material is easily obtained, reaction conditions are relatively mild, and the process is easy to industrialize. Compared with the original process, the process is shorter and less in three wastes.

The invention belongs to the technical field of organic synthesis, and specifically relates to a preparation method of 2,5-disubstituted-1,4-terephthalaldehyde. 2,5-disubstituted-1,4-terephthalaldehyde of the present invention is made of 2,5-disubstituted-1,4-dibromobenzene and DMF in hexamethylphosphoric triamide (HMPA) and tert-butyllithium It is produced under the catalytic action of oxidation reaction. Adding tert-butyllithium to the reaction system greatly improves the reaction activity, and with the help of a small amount of HMPA, the existence form of carbocations is stabilized. When tert-butyllithium and HMPA work together, the reaction yield is greatly improved, both at 78 % and above, greatly improving the efficiency of product quantification.