An Expedient Approach to the Synthesis of Chloroacetic, Dichloroacetic and Acetic Acid Catalyzed by Sulfuric Acid in the Presence of Crown Ethers.

ChemInform ◽  
2007 ◽  
Vol 38 (24) ◽  
Author(s):  
Shahnaz Perveen ◽  
Tahira B. Sarfaraz ◽  
Khalid M. Khan ◽  
Wolfgang Voelter
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Crown Ethers ◽  
Acid Catalyzed

scholarly journals Rearrangements in the acid-catalyzed formation of lactones from 2-hydroxynorbornane-2-acetic acid derivatives and related compounds

1992 ◽  
Vol 70 (9) ◽  
pp. 2491-2501 ◽  
Author(s):  
Peter Yates ◽  
Magdy Kaldas
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Ethyl Esters ◽  
Alkyl Groups ◽  
Acid Lactone ◽  
Concentrated Sulfuric Acid ◽  
Acid Catalyzed ◽  
Preliminary Study ◽  
Related Compounds ◽  
Acetic Acids

A mixture of the epimeric ethyl 2-hydroxynorbornane-2-acetates (1) on treatment with concentrated sulfuric acid is converted in turn to the lactones of exo-2-hydroxynorbornane-1-acetic acid (4), endo-6-hydroxynorbornane-endo-2-acetic acid (5), and exo-3-hydroxynorbornane-exo-2-acetic acid (6). With trifluoroacetic acid or 50% sulfuric acid, 1 gives 4, but this does not react further. In concentrated sulfuric acid the parent acids of 1 (7) and (E)- and (Z)-(norborn-2-ylidene)acetic acids (8 and 9) and their ethyl esters (10 and 11) give 6 as the infinity product. A mixture of 5-norbornene-endo- and exo-2-acetic acid (30 and 31) on treatment with 50% sulfuric acid gives 4, 5, 6, and exo-2-hydroxynorbornane-syn-7-acetic acid lactone (33). Routes are proposed for the formation of the lactones that involve protonation and carbocation formation followed by rearrangement via Wagner–Meerwein, endo-6,2-hydride, and exo-3,2-hydride shifts in decreasing order of preference. It is postulated that the usual inhibition of the rearrangement of tertiary to secondary norbornyl carbocations is not operative when the third substituent is a carboxymethyl group or its derivatives because of the electron-withdrawing properties of such groups relative to simple alkyl groups. A preliminary study has shown that exo-5-acetyloxy-endo-2-hydroxynorbornane-exo-2-acetic acid (35) with 50% sulfuric acid gives four products that are considered to be the γ-lactones of endo-5-acetyloxy- and endo-5-hydroxynorbornane-1-acetic acid (38 and 39) and exo-2-acetyloxy-1-hydroxy-and 1,2-dihydroxynorbornane-syn-7-acetic acid (40 and 41). Protonation of either the hydroxyl or acetyloxyl group is postulated, giving two carbocations that undergo rearrangements as in the case of 1, together with 3,2-hydroxyl shifts. The structures of the lactones are assigned on the basis of spectroscopy, reactivity, and analogy. The reactions of the lactones, which lead to a variety of hydroxy- and oxonorbornaneacetic acids, illustrate their synthetic potential.

Synthesis of 5-phenyl-10-methyl-7H- pyrimido[4,5-f][1,2,4]triazolo[4,3-a][1,4]diazepine and its evaluation as an anticonvulsant agent

1999 ◽  
Vol 77 (2) ◽  
pp. 216-222 ◽  
Author(s):  
Oludotun A Phillips ◽  
KS Keshava Murthy ◽  
Charles Y Fiakpui ◽  
Edward E Knaus
Keyword(s):  
Valproic Acid ◽  
Acetic Acid ◽  
Sulfuric Acid ◽  
Maximal Electroshock ◽  
Similar Reaction ◽  
Reaction Sequence ◽  
Anticonvulsant Agent ◽  
Acid Catalyzed ◽  
Benzoyl Radical ◽  
Predominant Product

The homolytic benzoylation (benzoyl radical) of 5-tert-butylcarbonylaminopyrimidine (6, 1 equiv.) in the presence of benzaldehyde (3 equiv.), water, sulfuric acid, and acetic acid, upon treatment with FeSO4·7H2O (3 equiv.) and 70% t-BuOOH (3 equiv.) at 5-10°C for 10 min afforded a mixture of 4-benzoyl-5-tert-butylcarbonylaminopyrimidine (7, 23%), 4,6-dibenzoyl-5-tert-butylcarbonylaminopyrimidine (8, 44%), and 4-benzoyl-5-tert-butylcarbonylamino-6- methyl pyrimidine (9, 10%). When a similar reaction was performed using 1 equiv. each of PhCHO, FeSO4·7H2O, and t-BuOOH, to prevent formation of the 4,6-dibenzoyl product 8, the monobenzoyl (7, 38%) and 4-benzoyl-6-methyl (9, 6%) products were obtained. A similar homolytic benzoylation of 5-bromopyrimidine (10) using 1.5 equiv. of reagents to generate the benzoyl radical afforded 4-benzoyl-5-bromopyrimidine (11, 61%) as the predominant product. Elaboration of 11 via a six-step reaction sequence afforded 2-hydrazino-5-phenyl-3H-pyrimido[5,4-e][1,4]diazepine (17) in 5.2% overall yield. The acid-catalyzed reaction of 17 with triethyl orthoacetate gave the title compound 5-phenyl-10-methyl-7H-pyrimido[4,5-f][1,2,4]triazolo[4,3-a][1,4]diazepine (18, 62%). The triazolo compound 18 was more potent than valproic acid (Depakene(r)) in both the subcutaneous metrazol (scMet) and maximal electroshock (MES) anticonvulsant screens, and more potent than clonazepam in the MES anticonvulsant screen but less potent than clonazepam in the scMet anticonvulsant screen.Key words: homolytic benzoylation, pyrimidines, pyrimidodiazepines, anticonvulsants.

scholarly journals Hydrothermal Pretreatment of Wheat Straw: Effects of Temperature and Acidity on Byproduct Formation and Inhibition of Enzymatic Hydrolysis and Ethanolic Fermentation

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 487
Author(s):  
Dimitrios Ilanidis ◽  
Stefan Stagge ◽  
Leif J. Jönsson ◽  
Carlos Martín
Keyword(s):  
Mass Spectrometry ◽  
Sulfuric Acid ◽  
Wheat Straw ◽  
High Performance ◽  
Enzymatic Saccharification ◽  
Hydrothermal Pretreatment ◽  
Gas Chromatography Mass Spectrometry ◽  
Enzymatic Digestibility ◽  
Acid Catalyzed ◽  
Pretreatment Conditions

Biochemical conversion of wheat straw was investigated using hydrothermal pretreatment, enzymatic saccharification, and microbial fermentation. Pretreatment conditions that were compared included autocatalyzed hydrothermal pretreatment at 160, 175, 190, and 205 °C and sulfuric-acid-catalyzed hydrothermal pretreatment at 160 and 190 °C. The effects of using different pretreatment conditions were investigated with regard to (i) chemical composition and enzymatic digestibility of pretreated solids, (ii) carbohydrate composition of pretreatment liquids, (iii) inhibitory byproducts in pretreatment liquids, (iv) furfural in condensates, and (v) fermentability using yeast. The methods used included two-step analytical acid hydrolysis combined with high-performance anion-exchange chromatography (HPAEC), HPLC, ultra-high performance liquid chromatography-electrospray ionization-triple quadrupole-mass spectrometry (UHPLC-ESI-QqQ-MS), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Lignin recoveries in the range of 108–119% for autocatalyzed hydrothermal pretreatment at 205 °C and sulfuric-acid-catalyzed hydrothermal pretreatment were attributed to pseudolignin formation. Xylose concentration in the pretreatment liquid increased with temperature up to 190 °C and then decreased. Enzymatic digestibility was correlated with the removal of hemicelluloses, which was almost quantitative for the autocatalyzed hydrothermal pretreatment at 205 °C. Except for the pretreatment liquid from the autocatalyzed hydrothermal pretreatment at 205 °C, the inhibitory effects on Saccharomyces cerevisiae yeast were low. The highest combined yield of glucose and xylose was achieved for autocatalyzed hydrothermal pretreatment at 190 °C and the subsequent enzymatic saccharification that resulted in approximately 480 kg/ton (dry weight) raw wheat straw.

Kinetics of the acid-catalyzed isomerization of phenylbutenes in glacial acetic acid

1972 ◽  
Vol 94 (4) ◽  
pp. 1247-1249 ◽  
Author(s):  
R. S. Schwartz ◽  
H. Yokokawa ◽  
E. W. Graham
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Acid Catalyzed ◽  
Kinetics Of

Antiaminic agents derived from thieno[2,3-c]-2-benzothiepin: 4-(1-Methyl-4-piperidylidene)-4,9-dihydrothieno[2,3-c]-2-benzothiepin and some related compounds

1983 ◽  
Vol 48 (2) ◽  
pp. 623-641 ◽  
Author(s):  
Zdeněk Polívka ◽  
Miroslav Rajšner ◽  
Jan Metyš ◽  
Jiří Holubek ◽  
Emil Svátek ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Sulfuric Acid ◽  
Title Compound ◽  
Amino Alcohol ◽  
Hydrogen Sulfate ◽  
Geometric Isomers ◽  
Pure Alcohol ◽  
Acid Catalyzed ◽  
Anticataleptic Activity ◽  
Related Compounds

In the reaction of thieno[2,3c]-2-benzothiepin-4(9H)-one (VI) with 1-methyl-4-piperidylmagnesium chloride 7-(1-methyl-4-piperidyl)thieno[2,3-c]-2-benzothiepin-4(9H)-one (VIII) is formed in addition to the expected amino alcohol VII. The title compound I was obtained by the acid catalyzed dehydration of the pure alcohol VII. Compound I (pipethiadene) has outstanding antihistamine, antiserotonin, antireserpine and anticataleptic activity and was recommended to clinical trials as a potential antimigraine agent. For pharmacokinetic and metabolic studies there were prepared the NC2H3 analogue of pipethiadene IV and further, as potential metabolites, the demethyl analogue III, S-oxide X, demethyl S-oxide XI, N-oxide XIII and N,S-dioxide XIV. The Witting reaction of the ketone VI with 3-dimethylaminopropylidenetriphenylphosphorane resulted in a mixture of geometric isomers of 4-(3-dimethylamino-propylidene)-4,9-dihydrothieno[2,3-c]-2-benzothiepin with the strongly predominating Z-isomer XVI which was isolated from the mixture by crystallization of the hydrogen maleate. The mixture with the predominating Z-isomer XVI was converted by the treatment with 80% sulfuric acid and dilution with water to a mixture with the predominating E-isomer XV (dithiadene) which was isolated by crystallization of the hydrogen sulfate. Some further new thieno[2,3-c]-2-benzothiepin derivatives were synthesized as potential intermediates.

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