- Synthetic method of aminothiazole compounds
-
The invention provides a synthetic method of aminothiazole compounds, and belongs to the technical field of medicine synthesis. The synthetic method comprises the following steps: step f, reacting a compound with a structure as shown in a formula (VI) with selenium dioxide to obtain a compound with a structure as shown in a formula (VII) and the like. The synthetic method of the aminothiazole compound is mainly used for synthesizing the aminothiazole compound, is easy to operate, simple in post-treatment, mild in reaction condition and high in final product yield.
- -
-
Paragraph 0085-0089
(2020/09/09)
-
- Hydrogenation of γ-Butyrolactone to 1,4-Butanediol over CuCo/TiO2 Bimetallic Catalysts
-
Titania-supported monometallic and bimetallic Cu-Co catalysts were prepared using (co)impregnation and studied for the hydrogenation of γ-butyrolactone (GBL) to 1,4-butanediol (BDO) at temperatures from 100 to 180 °C and a hydrogen pressure of 3.4 MPa. The highest catalytic activity occurred at a Cu:Co atomic ratio of 1:9 (Cu0.1Co0.9/TiO2), and a 95% yield of BDO was obtained. Characterization results showed mainly small nanoparticles (average size 2.6 nm) for pure Cu/TiO2, large particles (~19.8 nm) for pure Co/TiO2, and a bimodal particle size distribution of both small (~2.3 nm) and large (~16.5 nm) particles for the bimetallic catalyst with a Cu:Co ratio of 1:1. The addition of ~10 mol % Cu to Co/TiO2 increased the reducibility of the Co and resulted in the formation of core-shell CuCo bimetallic nanoparticles with a Co-rich core and Cu-rich shell. GBL hydrogenation in liquid ethanol and water produced an ester (ethyl 4-hydroxybutanoate) and a carboxylic acid (4-hydroxybutanoic acid) as the major products, respectively. GBL hydrogenation in 1,4-dioxane likely went through a 2-hydroxytetrahydrofuran (2-HTHF) intermediate. The 2-HTHF underwent facile ring-opening tautomerization to 4-hydroxybutanal (4-HB), followed by rapid hydrogenation to BDO at a reaction rate up to 700 times faster than GBL hydrogenation. The Cu0.1Co0.9/TiO2 catalyst maintained the BDO selectivity and about 80% of initial activity for GBL hydrogenation after 150 h time on stream in a continuous flow reactor.
- Huang, Zhiwei,Barnett, Kevin J.,Chada, Joseph P.,Brentzel, Zachary J.,Xu, Zhuoran,Dumesic, James A.,Huber, George W.
-
p. 8429 - 8440
(2017/12/08)
-
- HERBICIDAL ISOXAZOLO[5,4-B]PYRIDINES
-
The invention relates to isoxazolo[5,4-b]pyridine compounds of formula (I), to the agriculturally useful salts of isoxazolo[5,4-b]pyridine compounds of formula (I), and to their use as herbicides.
- -
-
Page/Page column 58
(2013/07/25)
-
- Oxidation of cyclic acetals by ozone in ionic liquid media
-
The application of ozone-stable pyrrolidinium based ionic liquids as safe reaction media resulted in selective hydroxy ester formation upon ozonation of cyclic acetals without using low temperatures or acetylating reagents.
- Van Doorslaer, Charlie,Peeters, Annelies,Mertens, Pascal,Vinckier, Chris,Binnemans, Koen,De Vos, Dirk
-
experimental part
p. 6439 - 6441
(2010/03/04)
-
- SULFONAMIDES AND PHARMACEUTICAL COMPOSITIONS THEREOF
-
The invention is directed to a class of compounds, including the pharmaceutically acceptable salts of the compounds, having the structure of formula (I), as defined in the specification. The invention is also directed to compositions containing the compounds of formula (I).
- -
-
Page/Page column 77-78
(2008/12/04)
-
- Trimethylaluminum (TMA)-catalyzed reaction of alkynyllithiums with ethylene oxide: Increased yields and purity of homopropargylic alcohols
-
An efficient protocol was developed to obtain homopropargylic alcohols. Subjecting alkynyllithiums and ethylene oxide to 10-20 mol% of trimethylaluminum provided homopropargylic alcohols in good yields. Georg Thieme Verlag Stuttgart.
- Brummond, Kay M.,McCabe, Jamie M.
-
p. 2457 - 2460
(2007/10/03)
-
- Relative rate profile for ring-closing metathesis of a series of 1-substituted 1,7-octadienes as promoted by a 4,5-dihydroimidazol-2-ylidene-coordinated ruthenium catalyst
-
(Matrix presented) This report details the kinetic responses of nine compounds of type 6 to ring-closing metathesis as promoted by 2 to give the identical product 7. The experimental observations have been subjected to Hammett analysis. The ρ value for the composite aromatic derivatives (R = p-XC6H4-) differs from that of the aliphatic series, although both are negative because electron-donating groups accelerate the reaction.
- Guo, Xin,Basu, Kallol,Cabral, Jose A.,Paquette, Leo A.
-
p. 789 - 792
(2007/10/03)
-
- Selective deprotection of isopropyl esters, carbamates and carbonates with aluminum chloride
-
The O-isopropyl bond of isopropyl esters, carbamates, and carbonates has been effectively and selectively cleaved by treatment with AlCl3 in nitromethane at 0-50 °C to give carboxylic acids, amines, and alcohols, respectively, in good to excell
- Chee
-
p. 1593 - 1595
(2007/10/03)
-
- Enantiomerically pure tetrahydro-5-oxo-2-furancarboxylic esters from dialkyl 2-oxoglutarates
-
Enantiomerically pure tetrahydro-5-oxo-2-furancarboxylic esters can be prepared either by enzymatic resolution of the racemic γ-lactones themselves or by bioreduction with baker's yeast of dialkyl 2-oxoglutarates and subsequent cyclization of the resulting dialkyl 2-hydroxyglutarates. The best results were obtained by the former route, by which the desired compounds were isolated in high enantiomeric excess. Bioreductions were less satisfactory. In fact the hydroxyester intermediates were initially formed as racemic mixtures and their final enantiomeric enrichment was reached by asymmetric destruction, occurring in the bioreaction medium, however at the same time large amounts of alkyl 4-hydroxybutanoates were formed as side products.
- Drioli, Sara,Nitti, Patrizia,Pitacco, Giuliana,Tossut, Laura,Valentin, Ennio
-
p. 2713 - 2728
(2007/10/03)
-
- Condensed benzazepine derivative and pharmaceutical composition thereof
-
This invention relates to nitrogen-containing aromatic 5-membered ring-condensed benzazepine derivatives represented by the general formula (I) STR1 (symbols in the formula have the following meanings; ring B: a nitrogen-containing aromatic 5-membered ring having at least 1 nitrogen atom and optionally one oxygen or sulfur atom, which may optionally have substituent(s), R1 and R2 : these may be the same or different from each other and each represents a hydrogen atom, a halogen atom, a lower alkyl group, an amino group which may optionally be substituted by lower alkyl group(s), or a lower alkoxy group, A: a single bond; a group represented by the formula n: 0 or an integer of from 1 to 3, R3 and R4 : these may be the same or different from each other and each represents a hydrogen atom, a lower alkyl group (provided that R3 and R4 may together form a lower alkylene group having 2 to 7 carbon atoms), and ring C: a benzene ring which may optionally have substituent(s)) and salts thereof; to pharmaceutical compositions which contain these compounds as an active ingredient and to intermediates which are useful in synthesizing these compounds. The compounds of this invention are useful as arginine vasopressin antagonists.
- -
-
-
- Enantiospecific Formation of Trans 1,3-Disubstituted Tetrahydro-β-carbolines by the Pictet-Spengler Reaction and Conversion of Cis Diastereomers into Their Trans Counterparts by Scission of the C-1/N-2 Bond
-
The factors which effect the stereoselective formation of trans-1-alkyl-2-benzyl-3-(alkoxycarbonyl)-1,2,3,4-tetrahydro-β-carbolines and trans-3-(alkoxycarbonyl)-1-alkyl-2-(diphenylmethyl)-1,2,3,4-tetrahydro-β- carbolines by the Pictet-Spengler cyclization were examined by heating tryptophan derivatives with aldehydes of varied steric bulk under aprotic and acidic conditions, followed by determination of the ratio of cis to trans diastereomers so formed. The presence of a benzyl group at the Nb-nitrogen atom alters the diastereochemical outcome of this condensation to provide 100% trans stereoselectivity when the cyclization is carried out with cyclohexanecarboxaldehyde. Furthermore, when Nb-(diphenylmethyl)tryptophan isopropyl ester was condensed with aldehydes of any size, trans diastereomers are formed with 100% stereoselectively. The trans Nb-substituted diastereomers are thermodynamically more stable than their cis congeners as shown by equilibration experiments in TFA. Conversion of the cis diastereomers into the more stable trans diastereomers is believed to occur under acidic conditions by cleavage of the carbon (C-1)-nitrogen (N-2) bond with complete retention of configuration at the C-3 stereocenter. Evidence from deuterium exchange experiments as well as optical rotations support this model for epimerization. In addition, when cis diastereomer 66a was allowed to stir in CF3COOD, the trans isomer 66b was isolated in 90% yield, while treatment of cis 66a with CF3COOH/NaBH4 provided a mixture of the ring cleaved [scission across C(1)-N(2) bond] product 67 and the trans isomer 66b. Treatment of 66b (control experiment) with NaBH4/CF3COOH under the same conditions returned only starting trans 66b in excellent yield. The Pictet-Spengler reaction of substrates with sufficiently large substituants, followed by treatment with acid, permits the 100% enantiospecific formation of trans-1,3-disubstituted-1,2,3,4-tetrahydro-β-carbolines for alkaloid total synthesis.
- Cox, Eric D.,Hamaker, Linda K.,Li, Jin,Yu, Peng,Czerwinski, Kevin M.,Deng, Li,Bennett, Dennis W.,Cook, James M.,Watson, William H.,Krawiec, Mariusz
-
-
- Aromatic annulation: Two new methods for the synthesis of chiral bicyclic phenols
-
Two selective and mild aromatic annulation procedures are described for the synthesis of chiral substituted tetrahydronaphthalene derivatives from (-)-menthone and (+)-dihydrocarvone.
- Corey,Palani, Anandan
-
p. 2397 - 2400
(2007/10/03)
-
- A convenient and mild procedure for the preparation of hydroxyesters from lactones and hydroxyacids
-
An alcoholic solution of lactones and hydroxyacids stored on Amberlyst-15 results in the formation of corresponding hydroxyesters in high yields.
- Anand,Selvapalam
-
p. 2743 - 2747
(2007/10/02)
-
- ASSYMETRIC REDUCTION OF KETONES BY GLYCEROL DEHYDROGENASE FROM GEOTRICUM
-
Glycerol dehydrogenase from Geotricum was used as a catalyst for asymmetric reduction of ketones.A 2-propanol-NAD couple was employed to supply NADH.
- Nakamura, Kaoru,Yoneda, Tetsuo,Miyai, Takehiko,Ushio, Kazutoshi,Oka, Shinzaburo,Ohno, Atsuyoshi
-
p. 2453 - 2454
(2007/10/02)
-
- SYNTHESIS OF RETROFRACTAMIDE A
-
The synthesis of the isobutylamide retrofractamide A is described.Key Word index - Piper retrofractum; Piperaceae; alkaloid; retrofractamide A; synthesis.
- Banerji, Avijit,Bandyopadhyay, Debabrata,Siddhanta, Arup K.
-
p. 3345 - 3346
(2007/10/02)
-
- Importance of allylic interactions and stereoelectronic effects in dictating the steric course of the reaction of iminium ions with nucleophiles. An efficient total synthesis of (±) gephyrotoxin
-
A stereocontrolled total synthesis of (±)-gephyrotoxin in 15 steps and 6.5% overall yield from benzyl trans-1,3-butadiene-1-carbamate is described. A key step is reduction of octahydroquinoline 27 from the more hindered concave α face to provide decahydroquinoline 28. This unusual transformation results from the interplay of allylic (A1,2) steric interactions and stereoelectronic effects.
- Overman,Lesuisse,Hashimoto
-
p. 5373 - 5379
(2007/10/02)
-
- Polar Substituent Effects in the Solvolysis of Primary and Tertiary Alkyl Halides. Polar Effect IX
-
When the Hammett-Taft equation log (k/k0) = ρq ?qi is applied to the solvolysis of the 3-substituted propyl bromides 6a-6i in ethanol/water 4:1 (v/v) log k correlates linearly with ?qI except in cases where R exerts an anchimetric effect.The reaction constant ρq for 6 is -0.12 and is typical for a nucleophilic solvent assisted ks process at a primary C-atom.The tertiary halides 1 and 3, however, which reacty with little or no nucleophilic solvent assistance, i.e. by kc processes, lead to larger ρq values of -0.71 and -1.14, respectively.The reacton constant ρq is therefore a sensitive gauge for charge development in the transition state for solvolysis of satured compounds.
- Grob, Cyril A.,Waldner, Adrian
-
p. 2152 - 2158
(2007/10/02)
-