Acetic Acid-acetic Anhydride Research Articles

SYNTHESIS, CRYSTAL STRUCTURE AND HIRSHFELD SURFACE ANALYSIS OF 1-ACETYL-5-(2-METHYLPROPYL)-2-THIOXO-IMIDAZOLIDIN- 4-ONE

The hydantoin and thiohydantoin heterocycles are present in a wide range of biologically active compounds including therapeutic drugs for the treatment of seizures and anti-tumor compounds. Thiohydantoins, have also been used as anti-convulsant agents and are present in fungicides, herbicides and natural products. However, the principal current interest comes from the application of thiohydantoins for the treatment of prostate cancers. Structural characterization of hydantoin and thiohydantoin are important to comprehend their effect mechanisms because of their considerable biological effects. In this work a thiohydantoin derivative, 1-acetyl-5-(2-methylpropyl)-2-thioxo-imidazolidin-4-one (I), has been obtained by the reaction of 2-amino-4-methylpentanoic acid with KSCN in acetic anhydride-acetic acid mixture. The heterocyclic compound was characterized by FTIR, NMR, powder and single-crystal X-ray diffraction analysis. This compound crystallizes in the triclinic system, space group P-1 (Nº2), Z=4, with two independent molecules in the unit asymmetric. The thiohydantoin (I) forms one-dimensional hydrogen bonded chains, via a single hydrogen bond between the carbonyl oxygens and the amine ring N3 position, that run along [100] direction, with graphset motif C(6). The nature of intermolecular interactions has been analyzed through Hirshfeld surfaces and 2D fingerprint plots.

ChemInform Abstract: Oxidative Substitution Reactions of Organostannyl Compounds with Lead Tetraacetate. A Convenient Route to 5-Alkylidene-2(5H)-furanones.

5-Substituted 2-tributylstannylfurans which were synthesized by the reaction of corresponding 5-substituted 2-lithiofurans with tributylstannyl chloride, were treated with two equimolar amounts of lead tetraacetate at room temperature to give corresponding 5-substituted 5-acetoxy-2(5H)-furanones in good yields. The 5-acetoxy-2(5H)-furanone was heated at 80 °C in acetic acid-acetic anhydride containing a catalytic amount of concentrated sulfuric acid to give 5-alkylidene-2(5H)-furanone in moderate yield.

Novel Fluoro Substituted Benzo[b]pyran with anti‐Lung Cancer Activity.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Catalytic Thermometric Titrations of Various Mixtures of Nitrogen Bases

The reactions of acetylation of hydroquinone and quinhydrone with acetic anhydride, catalysed by perchloric acid, were used to determine the end point of catalytic thermometric titrations of a number of different amines and amides dissolved either in acetic anhydride or in acetic acid-acetic anhydride (10+1) mixture. In the majority of cases primary and secondary amines could be successfully determined if pKbb≤9.3, tertiary amines if pKb≤14, and amides if pKb≤l5. Thanks to the difference in behaviour of organic bases in acety lation reaction, it was possible in some instances to determine selectively the individual bases in their mixtures. Catalytic titrations appeared to be especially suitable for the determination of extremely weak bases, even in the case of using mixtures of organic solvents, when Potentiometrie titrations could not be employed. Amounts of 2.5·10−6-8·10−5 mole of bases were determined with a maximal relative standard deviation less then 2%.

A simple approach towards the synthesis of oxadeazaflavines

The synthesis of oxadeazaflavine (2 H-chromeno[2,3- d]pyrimidine-2,4(3 H)-dione) derivatives ( 1a, 1b and 1c) from barbituric acid and salicylaldehydes as starting materials was shown to be possible using water as solvent at room temperature. The orange intermediate formed, an anthocyanidin-like precursor of the desired products, gave reasonable yields of the oxadeazaflavines when treated with acetic acid-acetic anhydride mixture. When the reaction was carried out at 100°C the corresponding 1,5-dihydro-5(5′-barbituryl)-2 H-chromeno[2,3- d]pyrimidine-2,4(3 H)-diones ( 4a, 4b and 4c) were obtained. The reaction of barbituric acid with nitrosalicylaldehydes, at either 25 or 100°C, leads only to the corresponding arylidenebarbituric acids.

Dielectric increments, intercharge distances and conformation of quaternary ammonioalkylsulfonates and alkoxydicyanoethenolates in aqueous and tirfluoroethanol solutions

ω-(Triethylammonio)alkane-α-sulfonates (H5C2)3N+–(CH2)n–SO3–(n= 2–4), pyridinio-, 2,6-lutidinio- and N-methylimidazolinio-propanesulfonates, and triethylammonioalkoxydicyanoethenolates (H5C2)3N+–(CH2)n–O–CO–C–(CN)2(n= 2, 3) have been studied by dielectric measurements (1 MHz–1 GHz) in dilute aqueous or trifluoroethanol solution. Their intercharge distances have been derived from their dipole moments (µ in the range 18–30 D) calculated according to Buckingham's theory, and compared with the maximum and minimum intercharge distances estimated by molecular mechanics for the ideal fully extended and ion-pair conformations respectively. For identical tether length, stronger charge delocalization in the cationic (imidazolinium versus pyridinium) or anionic (dicyanoethenolate versus sulfonate) sites slightly increases the intercharge distance, while better specific solvation of the zwitterions by hydrogen bonding in the less dissociating trifluoroethanol does not result in any significant conformational change with respect to aqueous solutions. Folding of the intercharge arm, negligible for 2-(triethylammonio)ethane-1 -sulfonate, progressively increases with its length, but the ion-pair conformation, where the intercharge distance becomes rapidly insensitive to the tether length, is never reached. This behaviour is in good agreement with the variations of the apparent ΔpKa values of the zwitterions (normalized to that of n-C4H9SO3H) measured by potentiometry in acetic anhydride-acetic acid (9:1, v/v) solution.

Oxidative Substitution Reactions of Organostannyl Compounds with Lead Tetraacetate. A Convenient Route to 5-Alkylidene-2(5H)-furanones

Abstract 5-Substituted 2-tributylstannylfurans which were synthesized by the reaction of corresponding 5-substituted 2-lithiofurans with tributylstannyl chloride, were treated with two equimolar amounts of lead tetraacetate at room temperature to give corresponding 5-substituted 5-acetoxy-2(5H)-furanones in good yields. The 5-acetoxy-2(5H)-furanone was heated at 80 °C in acetic acid-acetic anhydride containing a catalytic amount of concentrated sulfuric acid to give 5-alkylidene-2(5H)-furanone in moderate yield.

A practical system for manganese(III)-mediated electrochemical synthesis of sorbic acid precursors

An efficient, practical, electrochemical system was developed for the synthesis of a mixture of 4-acetoxy-5-hexenoic acid and trans-6-acetoxy-4-hexenoic acid via manganese (III)-mediated oxidation of acetic acid-acetic anhydride in the presence of butadiene. Copper (II) co-catalyst enhanced the efficiency of this oxidation and copper (I) was shown to catalyze in situ conversion of the acetoxyhexenoic acids into γ-vinyl-γ- butyrolactone.

ChemInform Abstract: Reduction of α‐Diketones and α‐Keto Esters with HI in Acetic Anhydride‐Acetic Acid.

ChemInform Abstract: Reduction of α‐Diketones and α‐Keto Esters with HI in Acetic Anhydride‐Acetic Acid.

ChemInform Abstract: The Action of Acetic Acid and/or Acetic Anhydride on Either Tetraphenyltin or Diphenyltin Oxide to Form Tin(IV) Acetate.

Abstract Tin(IV) acetate is prepared in nearly quantitative yield in only 4 hours from tetraphenyltin by the action of either a refluxing acetic acid-acetic anhydride mixture, or by acetic acid alone. Under anhydrous conditions neither tetraphenyltin nor diphenyltin oxide reacts with refluxing acetic anhydride alone over a period of four hours to give tin(IV) acetate. Likewise, refluxing glacial acetic acid alone with diphenyltin oxide over a period of four hours does not give tin(IV) acetate. However, it is obtained in nearly quantitative yield by the action of a refluxing acetic acid-acetic anhydride mixture on diphenyltin oxide over the same period of time.

Reduction of .alpha.-diketones and .alpha.-keto esters with hydrogen iodide in acetic anhydride-acetic acid

We have examined the reduction of α-diketones and α-keto esters in HI-acetic anhydride mixtures and found that the reaction gives good-to-excellent yields of α-acetoxy ketones and esters

Use of cumene hydroperoxide as an end-point indicator in the titration of bases by catalytic thermometric titrimetry

The use of the decomposition reaction of cumene hydroperoxide for indication of the end-point of the titration of organic bases with perchloric acid was investigated. The rise in temperature at the end-point is of the order of 25 °C. Only strong bases can be determined when the titrand solvent is acetic acid-acetic anhydride (92 + 8 v/v), but even weak bases such as caffeine can be determined in 1,2-dichloroethane. Some titration curves resulting from titration of bases with boron trifluoride (a Lewis acid) are presented.

An improved procedure for the conversion of amines to alcohols at low temperature

One of the best methods for converting aliphatic amines to alcohols involves thermal rearrangement of the corresponding N-nitrosoamides. This well-studied process continues to find new and useful applications. The normal experimental procedure for n-alkylamines entails isolating and heating the preformed N-nitrosamide 1 for several hours in a nonpolar solvent such as hexane, whereupon transient diazoester is produced. Smooth breakdown of the diazoester at 70-80{degree}C to the diazoalkane furnishes ester which can be saponified. The authors now report a milder procedure in which primary n-alkylamines are first converted to the corresponding trifluoro- or trichloroacetamides and then nitrosated at 0{degree}C in acetic acid-acetic anhydride.

The quantitative analysis of the polyester components of crosslinked silicone-polyester-aminoformaldehyde condensation products

Analysis of normally hydrolysis-resistant polymers, including silicone-polyesters, have recently been reported. Here we extend these methods to the analysis of condensation products of silicone-polyester resins and conventional butylated aminoplasts. Crosslinked systems employing butylated derivatives of urea-formaldehyde, melamine-formaldehyde and benzogaunamine have been degraded using an acetic acid-acetic anhydride reagent. Simultaneous hydrolysis of the polyester components and cleavage of both the ether crosslinks and the butoxy groups of the aminoplast occurred. Reaction conditions were also established where urea-formaldehyde, when used as a crosslinking agent, is simultaneously degraded using the same reagent. While the products were first examined as crosslinked condensation products, the procedures are also applicable to precondensation mixtures of the polyesters and the aminoplasts. The methods are suitable for quality control procedures.

The Action of Acetic Acid and/or Acetic Anhydride on Either Tetraphenyltin or Diphenyltin Oxide to Form Tin(IV) Acetate

Abstract Tin(IV) acetate is prepared in nearly quantitative yield in only 4 hours from tetraphenyltin by the action of either a refluxing acetic acid-acetic anhydride mixture, or by acetic acid alone. Under anhydrous conditions neither tetraphenyltin nor diphenyltin oxide reacts with refluxing acetic anhydride alone over a period of four hours to give tin(IV) acetate. Likewise, refluxing glacial acetic acid alone with diphenyltin oxide over a period of four hours does not give tin(IV) acetate. However, it is obtained in nearly quantitative yield by the action of a refluxing acetic acid-acetic anhydride mixture on diphenyltin oxide over the same period of time.

By-products in the analysis of β-muricholic acid in biological samples as methyl ester triacetate

By-products were formed on analysis of β-muricholic acid (3α,6β, 7β-trihydroxy-5β-cholan-24-oic acid) in biological samples by a method involving acid-catalyzed solvolysis of sulfate esters in acetone-methanol, followed by perchloric acid-catalyzed acetylation with acetic anhydride-acetic acid. These products have been identified by mass spectrometry and nuclear magnetic resonance as methyl 3-0,6-0-diacetyl-7-0-(1-methyl-3-oxo-1-butenyl)- and methyl 3-0,7-0-diacetyl-6-0-(1-methyl-3-oxo-1-butenyl)-β-muricholate, methyl 3-0,6-0-diacetyl- and methyl 3-0, 7-0-diacetyl-β-muricholate, and a methyl diacetoxy-cholen-24-oate.

Activation of molecular oxygen by copper salts in acetic acid and application to oxidation of 1,4-diphenylbutadiene and of 2,6-di-t-butylphenol: a 2,4-diphenylfuran synthesis

The stoichiometry and the kinetics of molecular oxygen absorption by the Cu(OAc) 2-LiBr system in solution in acetic acid-acetic anhydride (1:1) mixture has been investigated in the presence respectively of 1,4-dipheny1-1,3-butadiene ( 3) and of phenols as substrates. The former affords 2,5-diphenylfuran ( 5), whereas 2,6-di-t-butylphenol ( 10) leads to the formation of quinoid derivatives ( 12). The results are discussed on the basis of a duality of mechanism: the copper-LiBr catalyst used acts both as a dioxygen activation catalyst and as a halogenation system, this last aspect receiving further support from the copper halide-catalyzed oxidation of indene.

Crystal and molecular structures of 2,3,4,6-tetra- O-acetyl-1-bromo- d-galactopyranosyl cyanide and 2,3,4,5,7-penta- O-acetyl-β- d- galacto-2-heptulopyranosononitrile

2,3,4,6-Tetra- O-acetyl-1-bromo- d-galactopyranosyl cyanide ( 1) and 2,3,4,5,7-penta- O-acetyl-β- d- galacto-2-heptulopyranosononitrile ( 2) crystallise in the orthorhombic system; 1 has space group P2 12 12 1, with cell dimensions a = 7.256(1), b = 8.957(2), c = 29.450(3) Å, and 2 has space group P2 12 12 1, with a = 7.035(1), b = 15.080(2), c = 19.635(3) Å. The earlier observation, inferred from n.m.r. data, that the reaction of 1 with silver or mercury(II) acetate in acetic acid-acetic anhydride gave 2 with inversion of configuration at the cyanid-bearing carbon is substantiated. The presence of Br in 1 permitted establishment of the absolute configuration.

Copper-catalysed diacetoxylation of butadiene. Spectroscopic and physico-chemical investigations of the catalyst

The copper(II) acetate-lithium bromide catalysed diacetoxylation of butadiene has been investigated in the acetic acid-acetic anhydride system under oxygen pressure. The distribution of positional isomers (1,4/3,4) appeared to be little dependent on the reaction conditions, the 3,4-isomer (Scheme I, compound (4)) being the kinetically controlled one. A relatively slow interconversion of the isomers was observed under the reaction conditions. The catalytic system was investigated by 7Li NMR and UV spectroscopy, and the kinetics of oxygen absorption by the catalyst were determined; the roles of acetic anhydride and water at the catalyst level were thus established. The investigation of the behaviour of potential intermediates of the diacetoxylation reaction has been considered as another tentative approach to the understanding of the reaction mechanism.

Analysis of cross-linked alkyd amino formaldehyde resin systems

The analysis of the alkyd components of a cross-linked resin system with butylated urea, butylated melamine or butylated benzoguanamine formaldehyde resins is reported. Chemical cleavage of the ether links between the two resins and hydrolytic cleavage of the alkyd is achieved by acid reaction with p-toluenesulphonic acid-acetic anhydride, orthophosphoric acid or acetic anhydride-acetic acid reagents with the products being identified by gas chromatography as appropriate derivatives.