Search

A number of acetylated, naturally occurring, aroyl aryl glucosides have been subjected to mass-spectrometric examination. The identity of the aroyl group is readily determined from the mass spectrum. In the case of the 6-aroyl substituted glucosides, the fragmentation pattern has been shown to be definitive for the position of acyl substitution.

A procedure for the semimicrodetermination of carboxylic acids in the presence of a large excess of acyl chloride is described. Acyl chloride is first reacted with m -chloroaniline. The m -chloroaniline hydrochloride and carboxylic acid are then determined sequentially by potentiometric titration with sodium hydroxide. Titrations are performed in 80–90% p -dioxane to enhance the potentiometric breaks. With 0.05 N sodium hydroxide, as little as 0.01 m M of carboxylic acid can be determined.

1-Substituted benzimidazolinethiones, 3-substituted 1-acylbenzimidazolinethiones, and acyl thiobiurets, respectively, are formed in the reaction of acyl, alkyl, and aryl isocyanates with benzimidazolinethione, its 1-acyl derivatives, and thiourea. The IR and UV spectra of the compounds obtained are analyzed.

A kinetic study on the base-catalyzed acyl group-exchange reactions of N,O-diacyl-o-aminophenols was undertaken to show that the formation of the amidate ion should be the rate-determining step in these intramolecular acyl-exchange reactions, and that the electron-withdrawing power of acyl group becomes an important factor to control the relative stabilities of a pair of N,O-diacyl-o-aminophenols.

The synthesis of selected indole-3-aldehydes from the corresponding indoles and the DMF – acyl halide complex is described.

The acyl derivative of oxime, derived from a strong acid, is generally unstable. However, acyl oximes of the ethyl α-oximinoacetate derivative were prepared and were found to be more stable than ordinary acyl oxime. Acetyl, carbethoxy, benzoyl, and even tosyl ester were prepared, and their reactions with the mercaptide anion were investigated.

Reactions of 4-hydroxy-6-methyl-2-pyrone and 6-substituted 4-hydroxycoumarins with αβ-unsaturated acyl chlorides were carried out in pyridine or in tetrachloroethane containing titanium(IV) chloride. In the case of reactions carried out in pyridine, the ratio of two isomers formed was related to the substituents at the β-position of the αβ-unsaturated acyl chlorides and at the 6-position of the 4-hydroxycoumarin. A mechanism for these reactions is discussed.

2-Carbamoylimino- and 2-thiocarbamoylimino-4-oxo-3,4-dihydro-2H-benzo[e]-1,3-thiazine derivatives were obtained by condensation of thiosalicylic acid with 3-alkyl(aryl)-substituted cyanoureas and cyanothioureas. 2-Hydroxy-3-mercaptoquinoline-4-carboxylic acid reacts similarly.

The oxidation reactions of a series of opiates occuring at a glassy-carbon electrode in amperometric high-performance liquid chromatographic detection has been investigated. A structure-reactivity correlation has been drawn for morphone, morphinan and benzomorphan derivatives. Polarography and hydrodynamic voltammography were used to show the importance of phenolic groups to this reaction. Acyl substitution on the phenol did not prevent amperometric detection.

Lipases (triacylglycerol acylhydrolase, EC 3.1.1.3) have been used in organic media for the catalysis of reactions such as hydrolysis, esterification and transesterification. In these conditions it was confirmed that all reactions proceed through an acyl enzyme intermediate in two successive steps: acyl enzyme formation and solvolysis. The competition between two acyl acceptors (acyl donors) for reaction with a donor (acceptor) is described for the first time. A kinetic model is proposed using a competitive factor which is in good accordance with experimental results. The model was used successfully for the prediction of alcohol (acid) separations and resolutions by lipases.

The effect of N-substitution with various acyl groups at glucosamine residues on lysozyme-catalyzed hydrolysis of cell wall peptidoglycan and its oligosaccharides was studied. The lysozyme-resistant cell wall peptidoglycan from Bacillus cereus, N-unsubstituted at most of its glucosamine residues, was N-acylated and used as substrate for lysozyme. The N-acetylated, N-formylated, N-propionylated and N-butyrylated preparations of the peptidoglycan were hydrolyzed by lysozyme with relative maximum rates of 1.00, 0.05, 0.38 and 0.10 respectively, and with apparent Km values, expressed in disaccharide unit concentration, of 0.1, 0.6, 2.4 and 10 mM respectively, whereas the N-succinylated preparation was unsusceptible to this enzyme. Peptidoglycan oligosaccharides, GlcN-MurAc-GlcNAc-MurAc, GlcNAc-MurAc-GlcN-MurAc-GlcNAc-MurAc and GlcN-MurAc-GlcN-MurAc-GlcNAc-MurAc, were also N-acylated to be examined as substrates for lysozyme. The N-acetylated, N-formylated, N-propionylated and N-butyrylated preparations from the tetrasaccharide were hydrolyzed at 0.5 mM with relative rates of 1.00, 0.04, 0.1 and 0.01 respectively, but the N-succinylated tetrasaccharide was unaffected by lysozyme. The N-formylated, N-propionylated, N-butyrylated and N-succinylated preparations from the former hexasaccharide were hydrolyzed with relative rates of 1.5, 22, 1.6 and 0.8 respectively, as compared to the value of about 2000 for the N-acetylated hexasaccharide. The N-acylated preparations from the latter hexasaccharide, except the N-succinylated one, were hydrolyzed at rates similar to those of hydrolysis of the corresponding preparations from the former hexasaccharide. The above results seem to be accounted for by the predominant importance of the alkyl moieties of the N-acyl substituents on the glucosamine residues located in subsite C in the enzyme-substrate complexes.

Publisher Summary This chapter discusses the reaction of ammonia with acyl esters of carbohydrates. The processes that take place in this reaction include migrations, degradations, transesterifications, and deacylations, and their simultaneous occurrence makes the interpretation of the whole scheme very difficult. The chapter provides a general description of the facts and a discussion of the different variables that play a role in the yield of products formed and in the mechanisms involved. The reaction of acyl esters of aldoses and aldobioses with ammonia consists of a set of competitive pathways—including intramolecular 0 →N migrations of acyl groups, deacylations, and transesterifications, with formation of “aldose amides” and variable proportions of the free sugar as the principal products. Examination of acyl derivatives indicates whether a cyclic or an acyclic structure is present. A table of derivatives in the chapter, enlists the yield and properties of the products isolated from the reaction of ammonia with acylated mono- and disaccharides.

This study was designed to further elucidate relevance and mechanism of the positive inotropic action of cyclic N6-2′-O-dibutyryl-AMP (DB-c-AMP). For this purpose the effects of cyclic N6-monobutyryl-AMP (N6-MB-c-AMP), noncyclic N6-2′-O-3′-O-tributyryl-5′-AMP (TB-AMP), c-AMP, adenosine and various adenine nucleotides (ATP, ADP, AMP) on myocardial contractile force (CF) were investigated and compared to that of DB-c-AMP. The experiments were performed on isolated, electrically driven (frequency 2 Hz) rat left auricles, i.e. on a preparation in which DB-c-AMP consistently produced positive inotropic effects. The following results were obtained: From the failure of non-cyclic TB-AMP to increase contractile force it is concluded that the positive inotropic effects seen with cyclic DB-AMP and cyclic N6-MB-AMP are due to both acyl substitution and the intact cyclophosphate structure. In so far we probably have ruled out one of the objections to the view that the positive inotropic responses to acyl substituted derivatives of c-AMP are “representative” for c-AMP itself. Since the effects of cyclic DB-AMP and cyclic N6-MB-AMP were qualitatively similar and since the time course of the loss of the positive inotropic effects during washout were practically not differen with both drugs, one may further conclude that within the cell both drugs are likely to act via the same compound. This agent could be c-AMP. However, cyclic N6-MB-AMP as the active intracellular compound cannot be ruled out.

n/a

Publisher Summary This chapter describes the preparation and properties of amino acyl adenylates. Amino acyl adenylates are formed as enzyme-bound products activating enzyme. The amino acyl moiety of the enzyme-bound anhydride may be transferred to a suitable acceptor. There is evidence that the amino acyl moieties of enzyme-bound α -amino acyl adenylates are transferred to soluble ribonucleic acid acceptors and such RNA-amino acid complexes are generally believed to be intermediates in the incorporation of amino acids into proteins. The amino acyl moieties of enzyme-bound amino acyl adenylates may also be transferred to hydroxylamine to yield the corresponding amino acyl hydroxamates. Amino acyl adenylates have been prepared by condensing amino acid chlorides with silver adenosine 5′-phosphate. Amino acyl adenylates have also been prepared by condensing free amino acids with adenosine 5′-phosphate in the presence of N , N ′-dicyclohexylcarbodiimide. The preparation of glyeyl adenylate and leucyl adenylate through the corresponding benzyl mercaptoformyl derivatives has also been reported. The α -amino acyl adenylates are rapidly hydrolyzed in neutral aqueous solution to yield adenosine 5′-phosphate and amino acid, as judged by disappearance of the ability to form hydroxamic acids.

Thiocarbonyl S-imide of 1,2-dithiole-3-thione reacted with various acyl halides producing the corresponding N-phenylsulfonyl-1,2-benzodithiole-3-imine and elemental sulfur. The reaction was found to proceed via initial acylation on the nitrogen of the imide and was essentially acyl halide-catalyzed with regard to rearrangement.

Acyl silanes react with fluoride ion in the presence of water to give products arising either from intermediates equivalent to acyl anions or from rearrangements involving alkyl group migration from silicon to carbon, depending upon the reaction conditions.

Syntheses are reported for previously unreported acyl cyanophosphites upon the reaction of ethyl dicyanophosphite with carboxylic acid.