- One-pot production of diethyl maleate via catalytic conversion of raw lignocellulosic biomass
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The conversion of lignocellulose into a value-added chemical with high selectivity is of great significance but is a big challenge due to the structural diversities of biomass components. Here, we have reported an efficient approach for the one-step conversion of raw lignocellulose into diethyl maleate by the polyoxometalate ionic liquid [BSmim]CuPW12O40 in ethanol under mild conditions. The results reveal that all of the fractions in biomass, i.e., cellulose, lignin and hemicellulose, were simultaneously converted into diethyl maleate (DEM), achieving a 329.6 mg g-1 yield and 70.3% selectivity from corn stalk. Importantly, the performance of the ionic liquid catalyst [BSmim]CuPW12O40 was nearly twice that of CuHPW12O40, which can be attributed to the lower incorporation of the Cu2+ site in [BSmim]CuPW12O40. Hence, this process opens a promising route for producing bio-based bulk chemicals from raw lignocellulose without any pretreatment.
- Cai, Zhenping,Chen, Rujia,Zhang, Hao,Li, Fukun,Long, Jinxing,Jiang, Lilong,Li, Xuehui
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supporting information
p. 10116 - 10122
(2021/12/24)
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- Synthesis method of 2-formyl-4-carboxylic acid ethyl thiazole
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The invention discloses a synthesis method of 2-formyl-4-carboxylic acid ethyl ester thiazole, the synthesis method takes dichloroacetic acid, sodium ethoxide and ethanol as initial raw materials to firstly synthesize 2,2-diethoxyacetic acid ethyl ester, then ammonia water is added to ammoniate to obtain 2,2-diethoxyacetamide, the 2,2-diethoxyacetamide is converted into 2,2-diethoxythioacetamide through thioation by use of a vulcanizing reagent, then the 2,2-diethoxythioacetamide is condensed with 3-ethyl bromopyruvate to generate 2-diethoxymethyl-4-carboxylic acid ethyl ester thiazole, and finally acid deprotection is performed in an acetone solution to obtain the 2-formyl-4-carboxylic acid ethyl ester thiazole. According to the synthesis method of the 2-formyl-4-carboxylic acid ethyl ester thiazole, and the used raw materials are low in price, high in safety and easy to obtain. In addition, the synthesis method has the advantages of short synthesis route, high yield, high chemical purity of the obtained product, no need of complicated operation, and large-scale production.
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Paragraph 0017-0018; 0024; 0029-0030; 0035-0036; 0041-0042
(2019/11/18)
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- Evaluation of several routes to advanced pregabalin intermediates: Synthesis and enantioselective enzymatic reduction using ene-reductases
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This publication describes the evaluation of four synthetic routes to the advanced pregabalin (Lyrica) intermediate 7. Asymmetric reduction of (E)-7 with an ene-reductase (OPR1 from Lycopersicon esculentum) gave a saturated cyanoester intermediate 5 with the desired S stereocenter in ≥99% ee. OPR1 also catalyzed the reduction of (Z)-7 to (S)-5, but with lower conversion and selectivity.
- Debarge, Sebastien,McDaid, Paul,O'Neill, Pat,Frahill, James,Wong, John W.,Carr, Donncha,Burrell, Adam,Davies, Simon,Karmilowicz, Mike,Steflik, Jeremy
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p. 109 - 121
(2014/05/20)
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- METHOD FOR THE PRODUCTION OF ACETAMIDE ACETALS
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The invention relates to a method for production of acetamide acetals of formula (I), where R1 and R2 independently = C1-C6 alkyl, phenyl or benzyl, or together form a C2-C6 alkylene and R3 and R4 independently = H, C1-C6 alkyl or benzyl, or together form a C3-C6 alkylene, whereby a glyoxylate ester diacetal of formula (II), in which R1 and R2 are as above and R5 = C1-C4 alkyl, is reacted with DMF or an amine of formula (III) NHR4R5, where R4 and R5 are as above, in the presence of 0.005 to 3 Mol %, based on the amine of formula (III), of an alcoholate of formula (IV) XOC1-C4, where X = Na, K or Li, at a reaction temperature of 0 to 100 °C to give the corresponding compound of formula (I).
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- Pyrazole derivatives as herbicides
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PCT No. PCT/EP95/02435 Sec. 371 Date Jan. 6, 1997 Sec. 102(e) Date Jan. 6, 1997 PCT Filed Jun. 22, 1995 PCT Pub. No. WO96/01254 PCT Pub. Date Jan. 18, 1996Compounds of formula (I) in which the substituents W, R100, R101 and R102 are as defined 1; and the pyrazole N-oxides, salts, complexes and stereoisomer of the compounds of (I) have good pre- and post-emergence selective herbicidal properties. The preparation compounds and their use as herbicidal active compounds are described.
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- Etude de la composition de solutions aqueuses d'acide glyoxylique en RMN de 13C
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In order to determine the composition of aqueous solutions of glyoxylic acid, we studied the 13C nmr spectra of variously concentrated solutions (20 to 60 percent).The two well-separated regions (acids and esters on one side, acetals, hemiacetals and hydrates on the other) display not directly related intensities owing to the relaxation times of carbonyl carbons.Nevertheless, by plotting the relative intensity of each line in its own region, we were able to associate signals coming from the same species.Aside from the two prominent lines of monomeric hydrate, we identified two other pairs with intensity increasing with total concentration.Apart from a small line due to glyoxal and some other very small lines, we observed four lines of equal and slightly increasing intensity, three of acetal type and one of acid or ester type.In order to establish the structures of the species present, we determined the chemical shifts of a series of related molecules to be used as models (reported on table 2): first esters, acids, acetals, hemiacetals and hydrates of monomeric strukture, then dimers and trimers of acetaldehyde, ethyl glyoxylate and glyoxal.We were thus able to establish increments and correlations which allowed us to estimate the values of chemical shifts for possible dimers and trimers of glyoxylic acid: it was easy to see that two of the entities present in the solution are dimeric hemiacetals-acids, the erythro and threo isomers (figure 3).The fourth species is necessarily a combination of acid with glyoxal and the inspection of models led us to identify it as dihydroxy-4,5 dioxolan-1,3 carboxylic acid (figure 4).Its concentration was shown to increase with that of glyoxal in glyoxylic acid, and furthermore, some of its derivatives could be isolated.The acetalization and esterification of glyoxylic acid by ethanol in acidic medium, effected with remowal of water, provided a mixture of esters-acetals which was analysed by coupled VPC-mass spectrometry and VPC-chemical ionization (with ammonia).The analysis confirmed the existence of the above monomer and dimers in proportions related to the composition of the aqueous solution; moreover a small amount of a cyclic dimer is observed.No more than 5 percent of higher oligomers was evidenced.As for the combinations between glyoxal and glyoxylic acid, the principal one can be accompanied by many others, of various stoechiometries, when more glyoxal is initially present in the glyoxylic acid solution.Thus it is shown that glyoxylic acid in aqueous solution is mostly in the form of monomeric hydrate (69 to 88 percent)) and dimeric hemiacetals-acids (2,5 to 12 percent).Higher oligomers never exceed 5 percent in concentrated solutions, but glyoxal, if present, easily combines with glyoxylic acid, to form various compounds, the major one accounting for up to 12 percent of the material in some concentrated mixture of glyoxal and glyoxylic acid.
- Chastrette, Francine,Bracoud, Corinne,Chastrette, Maurice,Mattioda, Georges,Christidis, Yani
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- A Procedure for Diethoxymethylation of Ketones
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Reaction of a number of ketones with diethoxycarbenium fluoroborate in the presence of N,N-diisopropylethylamine at low temperature in methylene chloride results in a preparatively useful conversion to α-(diethoxymethyl) ketones.The method is compatible with arene, nitrile, chloride, and ester functional groups.With unsymmetrically substituted ketones, it is regioselective for the less substituted α-position.In favorable cases α,α'-dialkylation occurs.Conjugated ketones react normally at the saturated position adjacent to the carbonyl group.The mechanism of the reaction is considered.
- Mock, William L.,Tsou, Hwei-Ru
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p. 2557 - 2561
(2007/10/02)
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- Photoreaction of N,N'-Dibromo-2,5-piperazinedione
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The photolysis of N,N'-dibromo-2,5-piperazinedione in dichloromethane gave an unstable photoproduct.The alcoholysis of the photoproduct in the presence of a small amount of hydrogen bromide yielded 3,6-diethoxy-2,5-piperazinedione and its alcoholyzed products, ethyl diethoxyacetate, ethyl 2-(diethoxyacetylamino)-2-ethoxyacetate, N-(1-ethoxy-1-ethoxycarbonylmethyl)oxamide, and ethyl N-(diethoxyacetyl)glycinate.The reactions of the photoproduct with other nucleophiles also gave the corresponding substituted 2,5-piperazinediones.The structure of the primary photoproduct was deduced to be 3,6-dibromo-2,5-piperazinedione on the basis of these observations.
- Sera, Akira,Itoh, Kuniaki,Yamada, Hiroshi,Aoki, Ryuichi
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p. 3453 - 3455
(2007/10/02)
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