- An improved and scaleable preparation of 7-amino-3-vinylcephem-4-carboxylic acid
-
A practical and efficient multikilogram-scale preparation of 7-amino-3-vinylcephem-4-carboxylic acid (7-AVCA), a key intermediate used in the synthesis of cefixime and cefdinir, is described utilizing /p-methoxybenzyl 7-phenylacetamido-3-chloromethylcephe
- Chao, Mingyong,Hao, Aiyou
-
-
Read Online
- 7 - Amino -3 - vinyl cephalosporanic acid preparation method
-
The invention belongs to the technical field of medicine synthesis, and especially discloses a method for preparing 7-amino-3-vinyl cephalosporanic acid. The preparation method takes GCLE as an initial raw material, the GCLE and sodium iodide and triphenylphosphine are reacted in a mixing system of an organic solvent and water to generate phosphine salt, a certain amount of alkali lye is added in an organic phase for reacting to generate the corresponding phosphorus ylide, excess free alkali in an organic phase is removed through washing, formaldehyde and ylide are added for a wittig reaction, the organic phase is concentrated to a certain weight, phenol is added for removing carboxyl protection, amino protection is removed, crystallization is carried out to obtain 7-AVCA. The synthesis method does not require a mixing organic solvent, can realize recovery of sodium iodide and formaldehyde, has the advantages of high product yield, good quality, no three wastes generation, and environmental protection, and is suitable for large scale industrial production.
- -
-
-
- 7-phenylacetylamino-3-vinyl-4- spore olefine acid method for the preparation of P-methoxybenzyl ester
-
The invention discloses a preparation method of 7-phenylacetamido-3-vinyl-4-p-methoxy benzyl ester cefotaximate and belongs to the Chemical medicine field. The preparation method comprises the following steps: carrying out quaternary phosphorization and vinyl reaction at the same time on 7-phenylacetamido-3-chloromethyl-4-p-methoxy benzyl ester cefotaximate (GCLE), sodium iodide, triphenylphosphine and formaldehyde solution in a mixed system of dichloromethane, acetone and water to obtain 7-phenylacetamido-3-vinyl-4-p-methoxy benzyl ester cefotaximate; and removing 7-amino and 4-carboxyl protecting group according to known methods to prepare cefixime and cefdinir nuclear parent 7-AVCA (7-amino-3-vinyl-4-cephalosporanic acid). The aqueous phase comprising sodium iodide and excessive formaldehyde can be repeatedly applied, so that the utilization ratio of sodium iodide is remarkably improved, the production cost is lowered, and the environmental pollution caused by formaldehyde is reduced. The preparation method disclosed by the invention is low in production cost, simple in operating method and suitable for industrialized production and the raw materials are easily available in the preparation process.
- -
-
Paragraph 0021-0027
(2017/02/17)
-
- Synthesis of 3-alkenyl-Δ3-cephems via sequential reductive 1,2- elimination/ addition/cyclization in an alkenyltin/copper(I) chloride/bpy system
-
A sequential reductive 1,2-elimination-addition-cyclization of 3,4- disubstituted butenoates derived from penicillin is performed successfully by treatment with alkenyltin, copper(I) chloride and 2,2'-bipyridine (bpy) in N- methyl-2-pyrrolidinone (NMP) to afford 3-alkenyl-Δ3-cephems.
- Tanaka, Hideo,Tokumaru, Yoshihisa,Torii, Sigeru
-
p. 774 - 776
(2007/10/03)
-
- A facile synthesis of C(3)-alkenyl substituted cephems through addition-cyclization of allenecarboxylates derived from penicillin
-
A short-cut route to cephalosporins bearing alkenyl substituents on the C(3)-position through copper(I) chloride-promoted Michael-type addition of alkenyltributyltins to allenecarboxylates, derived from penicillin, is described.
- Tanaka, Hideo,Kameyama, Yutaka,Sumida, Shin-Ichi,Torii, Sigeru
-
p. 7029 - 7030
(2007/10/02)
-
- Palladium in Cephalosporin Chemistry: Mild Triflate Couplings in the Absence of Phosphines and Halide Donors
-
Palladium catalyzed triflate-organostannane couplings are shown to proceed in a very mild manner in the absence of added phosphine and halide reagents.This protocol has been demonstrated for 3-trifloxycephems and vinyltriflates.
- Baker, Stephen R.,Roth, Gregory P.,Sapino, Chester
-
p. 2185 - 2189
(2007/10/02)
-