17790-81-7Relevant articles and documents
SYNTHESIS OF DIMETHYL β-OXOADIPATE
Zav'yalev, S. I.,Zavozin, A. G.,Kravchenko, N. E.
, p. 1104 - 1106 (1991)
Acetoacrtic ester and Meldrum's acid provide a new and simple synthesis of dimethyl β-oxoadipate.This compounds is a synthone for some natural and biologically active compounds.
Synthesis, spectral properties and evaluation of carboxy-functionalized 3-thiazolylcoumarins as blue-emitting fluorescent labeling reagents
Dubey, Igor,Dubey, Larysa,Kuziv, Iaroslav
, (2020)
A series of UV-light excitable 7-hydroxy-, methoxy- and acetoxy-substituted [3-(thiazol-2-yl)]coumarin derivatives containing a carboxyalkyl functional group on the thiazole fragment were synthesized for the fluorescent labeling of biomolecules. The spectral properties of these compounds in methanol and aqueous buffers (pH 6.3 and 10.5) were studied. The dyes exhibit a bright blue fluorescence with maxima in the range of 438–457 nm and large Stokes shifts of 72–83 nm (in methanol). Emission maxima of the ionized forms of the 7-hydroxyl derivatives in basic medium are located at 482–484 nm. Thiazolylcoumarins are characterized by high fluorescence quantum yields (up to 0.85). Dye conjugates with L-trileucine and (2′-5′)-triadenylate were obtained via the active ester approach.
Method for synthesizing cefcapene pivoxil side chain acid intermediate methyl 4-bromoacetoacetate through micro-reaction
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Paragraph 0022, (2019/08/30)
Cefcapene pivoxil is an oral cephalosporin antibiotic with a strong antibacterial activity. The invention provides a method for synthesizing a cefcapene pivoxil side chain acid intermediate methyl 4-bromoacetoacetate through a micro-reaction, and belongs to the technical field of pharmaceutical chemical processes. The method comprises the following steps: diketene with a certain concentration andbromine are injected into a micro-channel reactor by two constant flow pumps according to a certain volumetric flow ratio, and are reacted at a low temperature to obtain a 4-bromo-3-oxobutyryl bromideeffluent, the effluent and methanol are respectively injected into a next micro-reactor by constant flow pumps according to a certain volume flow ratio, and are reacted to obtain an effluent containing methyl 4-bromoacetoacetate, and the effluent is rectified to obtain the methyl 4-bromoacetate. Compared with routine reactor methods, the method for synthesizing the cefcapene pivoxil side chain acid intermediate methyl 4-bromoacetoacetate through the micro-reaction has the advantages of rapidness in reaction, good selectivity, no catalyst and high efficiency in production, and allows the obtained methyl 4-bromoacetoacetate to have a purity of above 99% and a yield of above 95%.
Method for preparing cefcapene side chain acid
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Paragraph 0023; 0029; 0030, (2017/07/20)
The invention relates to a method for preparing cefcapene side chain acid, and belongs to the technical field of refined medical intermediates. The method comprises the following steps: adding ketene dimer into an alcohol organic solvent in the presence of nitrogen, dropwise adding bromine for reaction, adding a mixed liquid of dichloromethane and water for quenching reaction, separating an organic phase, adding acetic acid into the organic phase, dropwise adding propyl aldehyde and an organic alkali catalyst A for reaction, then adding thiourea for reaction, performing vacuum distillation for concentration, adding dichloromethane, di-tert-butyl dicarbonate ester and an organic alkali catalyst B into a concentrated solution for reaction, adding a caustic soda liquid for reaction, cooling, dropwise adding hydrochloric acid for crystallization, filtering, performing drip washing with an isopropanol solution, and drying, thereby obtaining (Z)-2-(2-t-butyloxycarboryl aminothiazole-4-yl)-2-pentenoic acid, that is, the cefcapene side chain acid. As the ketene dimer is adopted as an initial raw material, the method is small in side reaction, high in yield, high in purity of obtained products and gentle in reaction condition, and industrial production can be relatively easily achieved.
Synthesis and bioassay of racemic and chiral trans -α-Necrodyl Isobutyrate, the sex pheromone of the grape mealybug pseudococcus maritimus
Zou, Yunfan,Daane, Kent M.,Bentley, Walt J.,Millar, Jocelyn G.
experimental part, p. 4977 - 4982 (2011/07/31)
A concise synthesis of the racemic form of the female-produced pheromone of the grape mealybug was developed. The synthesis was readily adapted to production of both enantiomers of the pheromone via lipase-catalyzed kinetic resolution of an intermediate in the synthesis. Replicated field trials revealed that, contrary to a preliminary report, the (R,R)- rather than the (S,S)-enantiomer is the attractive stereoisomer. Lithium aluminum hydride reduction of the insect-produced compound to α-necrodol followed by analysis on a chiral stationary phase GC column showed that the insect-produced material was actually an 85:15 mixture of the (R,R)- and (S,S)-enantiomers. The racemic form of the pheromone was highly attractive to male mealybugs, and in one of two field bioassays, the racemic material was significantly more attractive than the pure (R,R)-enantiomer, suggesting that the (S,S)-enantiomer might act synergistically.
Development of new thiazole-based iridium catalysts and their applications in the asymmetric hydrogenation of trisubstituted olefins
Cheruku, Pradeep,Paptchikhine, Alexander,Ali, Muhammad,Neudoerfl, Joerg-M.,Andersson, Pher G.
, p. 366 - 373 (2008/10/09)
New thiazole-based chiral N,P-ligands that are open-chain analogues of known cyclic thiazole ligands have been synthesized and evaluated in the iridium-catalyzed asymmetric hydrogenation of trisubstituted olefins. Chirality was introduced into the ligands through a highly diastereoselective alkylation using Oppolzer's camphorsultam as chiral auxiliary. In general, the new catalysts are as reactive and selective as their cyclic counterparts for the asymmetric hydrogenation of various trisubstituted olefins. This journal is The Royal Society of Chemistry.
Process for producing 2-alkylidene-4-bromoacetoacetic acid ester
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, (2008/06/13)
A process for producing a 2-alkylidene-4-bromoacetoacetic acid ester of the formula (3): wherein R1and R2each independently represent a lower alkyl group having 1-5 carbon atoms, the process is characterized by reacting a 4-bromoacetoacetic acid ester of the formula (1): where R1has the same meaning as defined above, with an aldehyde of the formula (2): R2CHO??(2) wherein R2has the same meaning as defined above, in an inert organic solvent in the presence of an amine and a carboxylic acid.
Interactive design and synthesis of a novel antibacterial agent
Wolfe,Jin,Yang,Kim,McEachern
, p. 1051 - 1065 (2007/10/02)
β-Lactam compounds act on penicillin-recognizing enzymes via acylation of the hydroxyl group of an active site serine. When the resulting acyl enzyme is kinetically stable, as in the case of a penicillin-binding protein (PBP), the biosynthesis of a bacterial cell wall is inhibited, and death of the organism results. The de novo design of an antibacterial agent targeted to a PBP might be possible if the three-dimensional structural requirements of the equilibrium (i.e., fit) and catalytic (i.e. reactivity) steps of the aforementioned enzymatic process could be determined. For a model of the active site of a PBP from Streptomyces R61, the use of molecular mechanics calculations to treat 'fit,' and ab initio molecular orbital calculations to treat 'reactivity,' leads to the idea that the carboxyl group (G1) and the amide N-H (G2) of the antibiotic are hydrogen bonded to a lysine amino group and a valine carbonyl group in the enzyme-substrate complex. These two hydrogen bonds place the serine hydroxyl group on the convex face of the antibiotic, in position for attack on the β-lactam ring by a neutral reaction, catalyzed by water, that involves a direct proton transfer to the β-lactam nitrogen. Molecular orbital calculations of structure-reactivity relations associated with this mechanism suggest that C=N is bioisosteric to the β-lactam N-C(=O), comparable to a β-lactam in its reactivity with an alcohol, and that the product RO(C-N)H is formed essentially irreversibly (-ΔE > 10 kcal/mol). Accordingly, structures containing a G1 and a G2 separated by a C=N, and positioned in different ways with respect to this functional group, have been synthesized computationally and examined for their ability to fit to the PBP model. This strategy identified a 2H-5,6-dihydro-1,4-thiazine substituted by hydroxyl and carboxyl groups as a target for chemical synthesis. However, exploratory experiments suggested that the C=N of this compound equilibrates with endocyclic and exocyclic enamine tautomers. This required that the C2 position be substituted, and that the hydroxyl group not be attached to the carbon atom adjacent to the C=N. These conditions are met in a 2,2-dimethyl-3-(2-hydroxypropyl)-1,4-thiazine, which also exhibits the necessary fit to the PBP model. Two epimers of this compound have been synthesized, from D- and L-serine. The compound derived from L-serine is not active. The compound derived from D-serine exhibits antibacterial activity, but is unstable, and binding studies with PBP's have not been performed. It is hoped that these studies can be carried out if modification of the lead structure leads to compounds with improved chemical stability.
140. Construction of Highly Substituted Nitroaromatic Systems by Cyclocondensation. Part I. Synthesis of 4-Nitro-3-oxobutyrate
Duthaler, Rudolf O.
, p. 1475 - 1492 (2007/10/02)
Methyl 4-nitro-3-oxobutyrate (1) is prepared by substitution of 4-bromo- and 4-iodo-3-oxobutyrate enol ether or enol acetate derivatives with nitrite and deprotection of the keto function (Schemes 2 and 3).A much more convenient access to 1 is, however, t
