Acetylamino Group Research Articles

A simple and rapid concentration method for trace amounts of nickel(II), copper(II) and cadmium(II) with a polysaccharide "chitin" and maleonitriledithiolate ion.

A simple and rapid concentration method for 10-8mol dm-3 levels of nickel(II), copper(II) and cadmium(II) ions with maleonitriledithiolate ion(mnt2-) and chitin was developed. At pH5 protonated acetylamino groups of the chitin acted as an anion exchanger. Metal ions(M2+) reacted with mnt2- to form[M(mnt)2]2- complex, and adsorbed on the chitin. Ion exchange capacity of the chitin was 0.146mmol/g. More than 93% of the adsorbed [Ni(mnt)2]2- complex was able to be recovered with 1:1 mixture of ammonia buffer solution (0.2mol dm-3, pH10) and acetone. A recommended procedure: Pack chitin powder (0.5g) into a column (5cm3 syringe, i.d. 12mm). Take a sample solution(500 or 1000cm3) containing the metal ions was into a beaker. Add acetic acid-sodium acetate buffer solution (pH5) and Na2mnt([mnt2-]T=5×10-5mol dm-3). Allow the mixture to pass through the chitin column at a flow rate of 120150cm3/min and elute the adsorbed complexes with 10cm3 of a 1:1 mixture of ammonia buffer solution and acetone. The recovery for 10-810-7mol dm-3 levels of nickel(II) and copper (II) ions were more than 90% with a concentration ratio of 50 or 100 and that of cadmium(II) ion was about 85%. This method was successfully applied to the determination of 10-7mol dm-3 levels of copper(II) ion in residual water of the water distilling apparatus by flame AAS.

Cyclic melanotropins

The highly potent cyclic analogue of alpha-MSH, Ac-[Cys4,Cys10]-alpha-MSH4-13-NH2, was structurally modified in position 4. Four analogues were prepared and their biological activities in the in vitro frog and lizard skin bioassays were determined. It was shown that removing the terminal acetylamino group to give [Mpa4,Cys10]-alpha-MSH4-13-NH2 resulted in little change in the biological activity, but a change in the stereochemistry of cysteine in position 4 to give Ac-[D-Cys4,Cys10[-alpha-MSH4-a3-NH2 led to a small decrease of activity in both bioassays. Decreasing the size of the intramolecular ring by removing one methylene group to give [Maa2,Cys10]-alpha-MSH4-13-NH2, resulted in an analogue with lower activities in both assays (about 3 times in the lizard and 500 times in the frog), and increasing the size of the righ by methylene group to give Ac-[Hcy4,Cys10]-alpha-MSH4-13-NH2 led to much lower activities in the lizard system and similar effects were seen upon decreasing the ring size in the frog skin assay.

Functionalized derivatives of dibenzo [c,j] dipyrazolo-[3,4-f∶3′,4′-m] [1,2,5,8,9,12] hexaazacyclotetradecinate

A number of derivatives of dibenzo [c,j] dipyrazolo [3,4-f∶3′,4′-m] [1,2,5,8,9,12]-hexaazacyclotetradecinate with peripheral nitro, amino, and acetylamino groups have been synthesized.

Hog pancreatic α-amylase; N-terminal sequence analysis

Both isozymes of hog pancreatic amylase were digested with chymotrypsin, subtilisin and pronase. These digests were passed over a column of sulfoethyl-Sephadex C-25 and peptides not containing free NH2-groups thus isolated. It was shown that both isozymes have the same N-terminal amino acid sequence, pyrrolidonecarboxylic acid - tyrosine. No peptides with acetylated amino groups were found.

Complexes of lanthanide nitrates with 2‐n‐acetylaminopyrimidine

AbstractNew complexes of lanthanide nitrates with 2‐N‐acetylaminopyrimidine (ApymH) of the composition Ln(ApymH)2 (NO3)3 where Ln = La‐Yb and Y have been synthesised and characterised by conductance, infrared, 13C and 1H NMR (for La3+ and Y3+ complexes only) and electronic spectra. The molar conductance and infrared spectral data show that all nitrate groups are coordinated to the metals. IR and NMR evidence point to the bidentate chelation of the ligand through the pyrimidine nitrogen and oxygen of the acetylamino group. A probable coordination number of ten has been assigned for all the complexes.

Synthesis and Antimicrobial Properties of Alkylbenzoylacrylic Acid Derivatives

Water soluble alkali metal salts of butyl, octyl and dodecylbenzoylacrylic acids were derived from the corresponding less soluble alkylbenzoylacrylic acids. And the antimicrobial activity and surface tension of their aqueous solutions were examined. They show the antimicrobial activity significantly against Gram positive bacilli, but lesser extent against Gram negative bacilli and fungi. For the antimicrobial activity, octylbenzoyl acrylate is superior and for the surface activity, 3- (2-hydroxy-3-octylbenzoyl) acrylate is superior. Then the effect of the introduction of hydroxyl or acetylamino group to the alkylbenzoyl acrylic acid on the antimicrobial power and surface activity were also compared.

EFFECT OF ACETYLATION AND METHYLATION ON THE SWEETNESS INTENSITY OF THAUMATIN I

The lysine residues in thaumatin I were chemically modified by acetylation with acetic anhydride and by reductive methylation, under various conditions. The acetylated and methylated thaumatins were isolated by ion-exchange chromatography. The number of remaining free amino groups was determined by trinitrophenylation. At least four acetylated thaumatins with either one, two, three or four acetylated amino groups were obtained as well as one methylated thaumatin with six dimethyl lysine residues and one monomethyl lysine residue. The sweetness intensity of the acetylated thaumatins decreased with the increasing number of acetylated amino groups; the sweet taste had disappeared completely when four amino groups were acetylated. The methylated thaumatin with seven modified lysine residues had a sweetness intensity practically equal to that of the original thaumatin. The total net change, i.e. the isoelectric point of thaumatin, might play a role in the physiological behaviour of thaumatin causing a sweet taste sensation.

The Inhibition of Macrophage Migration Inhibitory Factor

SummaryAnalogs of EACA were capable of inhibiting the in vitro activity of macro-phage migration inhibitory factor (MIF). The most active analog of EACA in terms of MIF inhibition had four methyl groups separating an acetylated amino group from a free carboxyl group. This compound, acetylated 5-amino valeric acid, was capable of inhibiting completely MIF activity in vitro at a concentration of less than 10−6M without demonstrating any appreciable anti-tryptic activity, even at 10−3M. Anti-tryptically active EACA did not inhibit MIF except at very high concentrations (10−2M). Further, the most purified preparations of MIF obtained from aqueous extracts of thymus that we have studied contained no significant proteolytic activity upon denatured hemoglobin at pH 3-8. Therefore, we do not correlate anti-tryptic with anti-MIF activity in vitro.

Infrared spectroscopic study of the conformations assumed, in solution, by β‐diamides considered as model compounds for the repeating unit in poly amides synthesized from β‐amino and β‐imino acids

AbstractIn order to get a closer understanding of the conformational features displayed by poly‐amides obtained from different β‐amino and β‐imino acids, a systematic investigation was carried out with three sets of model β‐diamides. equation image Very dilute solutions in carbon tetrachloride were studied by infrared spectroscopy in the 3200‐3500 cm−1 frequency range which includes the vNH stretching absorption bands.Depending on the substitution of the middle aliphatic sequence, molecules I (R, R') mainly assume either a stretched form (when R = H in β‐alanine derivatives) or a folded six‐membered ring conformation (when R = Me in the compounds synthesized from β‐aminobutyric acid). This latter conformer is stabilized by an intramolecular hydrogen bonding.A similar behavior was evidenced with N‐dimethylated species III(R). The β‐alanine derivative III(H) was found to be in an open form, whereas, the β‐aminobutyric analogous diamide III(Me) assumed a folded structure. In this latter case, however, it was shown that the folding is mainly governed by a NH…π interaction between the NH group and the π orbital of the tertiary amide function.On the other hand, the N‐methylation of the acetylamino group in models II(R) produces preferentially an eight‐membered ring chelate which is stabilized by an intramolecular hydrogen bonding involving the NH of the C‐terminal amide function and the highly nucleophilic CO in the N‐methylated acetylamino group.Each of the evidenced conformers is described by a set of three rotational angles and is experimentally characterized by its specific spectroscopic features.

Reversed action of acetylated corticotrophin: inhibition of adreno-cortical secretion.

ABSTRACT A derivative of corticotrophin with acetylated amino groups and hydroxyl groups in serine was used. Acetylated corticotrophin significantly decreased the 17-hydroxycorticosteroid (17-OHCS) level in the plasma of guineapigs 4 hours after the i. m. injection of the derivative in a dose equal to 2.5 USP units of the active hormone per 100 g of body weight. The mean plasma 17-OHCS concentration before the injection of the derivative was 44 ± 2.15 μg/100 ml. After the injection of acetylated corticotrophin, the fall in 17-OHCS content was highly significant, the average level being decreased to 61 %. However, in 12 out of 36 animals there was a fall to 30 % of the initial level. The derivative obtained may be considered as an »anahormone«, and probably has the ability to inhibit the secretion of endogenous corticotrophin.

N-acetyl-β-alanine deacetylase in hog kidney

1. (1) An enzyme which catalyzed the hydrolysis of the acetylamino group of N-acetyl-β-alanine was found in mammalian kidney. 2. (2) The enzyme was purified to about 100 fold from hog kidney. 3. (3) The optimal pH of the enzyme was 7.6 K m value for acetyl-β-alanine was 2.5·10 −3 M and the enzyme was inhibited by p-chloromercuribenzoate and monoiodo-acetate. 4. (4) Among various acylamino acids tested so far, N-acetyl-β-alanine and to less extent N-acetyl-taurine served as the substrate. 5. (5) A name N-acetyl-β-alanine amidohydrolase (trivial name: N-acetyl-β-alanine deacetylase) was suggested.

Solvent effects on the infra-red spectra of anilines—III. Acetanilides

Solvent effects on the NH stretching frequency of a number of acetanilides have been examined. The frequency shifts cannot be used as a unique test for intramolecular hydrogen bonds. The ability of a solvent to break the intramolecular hydrogen bond is partly determined by the energy required to rotate the acetylamino group into a position which allows access of the solvent to the amino hydrogen atom.

Directive Influence of the Acetylamino Group in the Friedel--Crafts Acylation of the Diacetylaminonaphthalenes

Directive Influence of the Acetylamino Group in the Friedel--Crafts Acylation of the Diacetylaminonaphthalenes

Directive Influence of the Acetylamino Group in the Friedel--Crafts Acylation of the Acetylaminonaphthalenes

Directive Influence of the Acetylamino Group in the Friedel--Crafts Acylation of the Acetylaminonaphthalenes

Steric effects on mesomerism. III). Estimation of the direct influence of substituents on the rate of deacylation ofortho‐ andpara‐nitro‐acetanilide

AbstractThis paper contains data on the rates of “catalytic” deacylation of derivatives ofortho‐ andpara‐nitro‐acetanilide in which steric effects on mesomerism are absent, especially 1‐acetylamino‐2‐nitro‐4‐R‐benzene, 1‐acetyl‐amino‐2‐nitro‐5‐R‐benzene and 1‐acetylamino‐4‐nitro‐6‐R‐benzene. Comparison of these rates with those ofortho‐ orpara‐nitro‐acetanilide gives the (“direct”) influence of the respective substituents inpara‐, meta‐ andortho‐position to the acetylamino group. The results, which will be used in subsequent papers, are nearly always in qualitative agreement with current electronic theory.

Societies and Academies

LONDON. Royal Society, Feb. 12.—J. Cohen, K. Cooper, and P. G. Marshall: Some aliphatic and aromatic amino derivatives of α-quinoline methodide. Many of the amino and acylamino compounds obtained by the condensation of derivatives of α-methyl quinoline with nitrosoarylamines possess active antiseptic and in some cases mild trypanocidal properties. Substances obtained by attaching a basic aliphatic or aromatic side-chain directly to the α-carbon of the quinoline nucleus exhibited no marked antiseptic or trypanocidal character. Diamino compounds of aliphatic and aromatic series with basic groups at both ends of the chain did not exhibit the expected anti-malarial action.—C. H. Browning, J. B. Cohen, S. Ellingworth, and R. Gulbransen: The antiseptic and trypanoidal action of certain styryl and anil benzthiazole derivatives. The anil benzthiazole derivatives are relatively weakly antiseptic for Staphylococcus and B. coli, as compared with the quinoline analogues, which are highly aqtive in this respect. Several benzthiazole styryl compounds have produced cure of mice infected with Trypanosoma brucei, and the same relationships between chemical constitution and trypanocidal action have been found to hold as in the styryl quinoline series. Thus the maximum effect is produced when one nucleus contains a basic group and the other an acetylamino group. The anil benzthiazole series, in general, possesses some trypanocidal action, but cure has only exceptionally been produced.