scholarly journals Crystallization-induced amide bond formation creates a boron-centered spirocyclic system

2017 ◽  
Vol 23 (3) ◽  
pp. 167-169 ◽  
Author(s):  
Brighid B. Pappin ◽  
Stephan M. Levonis ◽  
Peter C. Healy ◽  
Milton J. Kiefel ◽  
Michela I. Simone ◽  
...  
Keyword(s):  
Amide Bond ◽  
Lewis Acidity ◽  
Carbonyl Groups ◽  
Amide Hydrogen ◽  
Tetrahedral Complex ◽  
Packing Structure ◽  
Amide Bond Formation ◽  
Amide Carbonyl ◽  
Crystallization Conditions ◽  
Aminophenylboronic Acid

AbstractThe 5-nitrosalicylate ester of 2-acetamidophenylboronic acid (C15H10BN2O6) is formed under crystallization conditions from the 5-nitrosalicylate ester of 2-aminophenylboronic acid. The boron at the center of this structure exists as a tetrahedral complex produced by a dative bond with the amide carbonyl. The perpendicular shape produces an unusual packing structure including a bifurcated hydrogen bond between the amide hydrogen and carbonyl groups on two neighboring molecules. We propose that this reaction occurs due to increased Lewis acidity of the nitrosalicylate ester of 2-aminophenylboronic acid.

The structure of a valinomycin–hexaaquamagnesium trifluoromethanesulfonate compound

2016 ◽  
Vol 72 (8) ◽  
pp. 627-633
Author(s):  
Megumi Fujita ◽  
Amaan M. Kazerouni ◽  
John Bacsa
Keyword(s):  
Hydrogen Bonds ◽  
Metal Binding ◽  
Binding Mode ◽  
Cation Binding ◽  
Acetonitrile Solution ◽  
Binding Modes ◽  
Carbonyl Groups ◽  
Amide Hydrogen ◽  
Amide Carbonyl

Valinomycin is a naturally occurring cyclic dodecadepsipeptide with the formulacyclo-[D-HiVA→L-Val →L-LA→L-Val]3(D-HiVA is D-α-hydroxyisovaleic acid, Val is valine and LA is lactic acid), which binds a K+ion with high selectively. In the past, several cation-binding modes have been revealed by X-ray crystallography. In the K+, Rb+and Cs+complexes, the ester O atoms coordinate the cation with a trigonal antiprismatic geometry, while the six amide groups form intramolecular hydrogen bonds and the network that is formed has a bracelet-like conformation (Type 1 binding). Type 2 binding is seen with the Na+cation, in which the valinomycin molecule retains the bracelet conformation but the cations are coordinated by only three ester carbonyl groups and are not centrally located. In addition, a picrate counter-ion and a water molecule is found at the center of the valinomycin bracelet. Type 3 binding is observed with divalent Ba2+, in which two cations are incorporated, bridged by two anions, and coordinated by amide carbonyl groups, and there are no intramolecular amide hydrogen bonds. In this paper, we present a new Type 4 cation-binding mode, observed in valinomycin hexaaquamagnesium bis(trifluoromethanesulfonate) trihydrate, C54H90N6O18·[Mg(H2O)6](CF3SO3)2·3H2O, in which the valinomycin molecule incorporates a whole hexaaquamagnesium ion, [Mg(H2O)6]2+,viahydrogen bonding between the amide carbonyl groups and the hydrate water H atoms. In this complex, valinomycin retains the threefold symmetry observed in Type 1 binding, but the amide hydrogen-bond network is lost; the hexaaquamagnesium cation is hydrogen bonded by six amide carbonyl groups.1H NMR titration data is consistent with the 1:1 binding stoichiometry in acetonitrile solution. This new cation-binding mode of binding a whole hexaaquamagnesium ion by a cyclic polypeptide is likely to have important implications for the study of metal binding with biological models under physiological conditions.

scholarly journals Microbiological degradation of bile acids. Metabolites formed from 3-(3a α-hexahydro-7a β-methyl-1,5-dioxoindan-4 α-yl) propionic acid by Streptomyces rubescens

1977 ◽  
Vol 164 (3) ◽  
pp. 715-726 ◽  
Author(s):  
S Hashimoto ◽  
S Hayakawa
Keyword(s):  
Propionic Acid ◽  
Bond Formation ◽  
Amide Bond ◽  
Side Chain ◽  
Carbonyl Groups ◽  
Dioic Acid ◽  
Amide Bond Formation ◽  
Alpha Beta ◽  
Compound Ii ◽  
New Compounds

1. The metabolism of 3-(3a alpha-hexahydro-7a beta-methyl-1,5-dioxoindan-4 alpha-yl)propionic acid (III), which is a possible precursor of 2,3,4,6,6a beta, 7,8,9,9a alpha,9b beta-decahydro-6a beta-methyl-1H-cyclopenta[f]quinoline-3,7-dione (II) formed from cholic acid (I) by streptomyces rubescens, was investigated by using the same organism. 2. This organism effected amide bond formation, reduction of the carbonyl groups, trans alpha beta-desaturation and R-oriented beta-hydroxylation of the propionic acid side chain and skeleton cleavage, and the following metabolites were isolated as these forms or their derivatives: compound (II), 1,2,3,4 a beta,-5,6,6a beta,7,8,9a alpha,9b beta-dodecahydro-6a beta -methylcyclopental[f][1]benzopyran-3,7-dione (IVa), (1R)-1,2,3,4a beta,5,6,6a beta,7,8,9.9a alpha,9b beta-dodecahydro-1-hydroxy-6a beta-methylcyclopenta[f][1]benzopyran-3,7-dione (IVb), (E)-3-(3aalpha-hexahydro-5 alpha-hydroxy-7a beta-methyl-l-oxo-indan-4 alpha-yl)prop-2-enoic acid (V), (+)-(5R)-5-methyl-4-oxo-octane-1,8-dioic acid (VI), 3-(4-hydroxy-5-methyl-2-oxo-2H-pyran-6-yl)propionic acid (VII) and 3-(3a alpha-hexahydro-1 beta-hydroxy-7a beta-methyl-5-oxoindan-4 alpha-yl)propionic acid (VIII). The metabolites (IVb), (V), (VI) and (VII) were new compounds, and their structures were established by chemical synthesis. 3. The question of whether these metabolites are true degradative intermediates is discussed, and a degradative pathway of compound (III) to the possible precursor of compound (VII), 7-carboxy-4-methyl-3,5-dioxoheptanoyl-CoA (IX), is tentatively proposed. The further degradation of compound (IX) to small fragments is also considered.

Diethylphosphoryl-OxymaB (DEPO-B) as a Solid Coupling Reagent for Amide Bond Formation

2018 ◽  
Vol 16 (1) ◽  
pp. 30-33
Author(s):  
Ashish Kumar ◽  
Yahya E. Jad ◽  
Ayman El-Faham ◽  
Beatriz G. de la Torre ◽  
Fernando Albericio
Keyword(s):  
Bond Formation ◽  
Hydrolytic Stability ◽  
Solid Material ◽  
Amide Bond ◽  
Amide Bond Formation ◽  
Coupling Reagent

A new phosphonium based coupling reagent DEPO-B has been synthesized from 5- (hydroxyimino)-1,3-dimethylpyrimidine-2,4,6 (1H,3H,5H)-trione (Oxyma B) and diethyl chlorophosphate in presence of base. It is a solid material and the hydrolytic stability and solubility was evaluated for confirming its capability for usage in automated peptide synthesizer.

A Review of Amide Bond Formation in Microwave Organic Synthesis

2014 ◽  
Vol 11 (4) ◽  
pp. 592-604 ◽  
Author(s):  
Natalia Lukasik ◽  
Ewa Wagner-Wysiecka
Keyword(s):  
Organic Synthesis ◽  
Bond Formation ◽  
Amide Bond ◽  
Amide Bond Formation

scholarly journals 4-[(2,4-Dichlorophenyl)carbamoyl]butanoic Acid

Molbank ◽  
10.3390/m1227 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1227
Author(s):  
Bibi Hanifa ◽  
Muhammad Sirajuddin ◽  
Zafran Ullah ◽  
Sumera Mahboob ◽  
See Mun Lee ◽  
...  
Keyword(s):  
Torsion Angle ◽  
Acid Amide ◽  
Spectroscopic Characterization ◽  
Amide Bond ◽  
Amide Hydrogen ◽  
Butanoic Acid ◽  
X Ray ◽  
Amide Derivative

The synthesis and spectroscopic characterization of the glutaric acid-amide derivative, 2,4-Cl2C6H3N(H)C(=O)(CH2)3C(=O)OH (1), are described. The X-ray crystal structure determination of (1) shows the backbone of the molecule to be kinked about the methylene-C–N(amide) bond as seen in the C(p)–N–C(m)–C(m) torsion angle of −157.0(2)°; m = methylene and p = phenyl. An additional twist in the molecule is noted between the amide and phenyl groups as reflected in the C(m)–N–C(p)–C(p) torsion angle of 138.2(2)°. The most prominent feature of the molecular packing is the formation of supramolecular tapes assembled through carboxylic acid-O–H…O(carbonyl) and amide-N–H…O(amide) hydrogen bonding.

A computational study on the mechanism of ynamide-mediated amide bond formation from carboxylic acids and amines

2017 ◽  
Vol 15 (30) ◽  
pp. 6367-6374 ◽  
Author(s):  
Song-Lin Zhang ◽  
Hai-Xing Wan ◽  
Zhu-Qin Deng
Keyword(s):  
Reaction Mechanism ◽  
Carboxylic Acids ◽  
Computational Study ◽  
Bond Formation ◽  
Amide Bond ◽  
Reactivity Pattern ◽  
Amide Bond Formation ◽  
Coupling Reagent ◽  
Catalytic Effects ◽  
Acid Substrate

A detailed computational study is presented on the reaction mechanism of ynamide-mediated condensation of carboxylic acids with amines to produce amides, which elucidates the reactivity pattern of the coupling reagent ynamide and discloses crucial bifunctional catalytic effects of the carboxylic acid substrate during aminolysis.

Green Amide Bond Formation in Water via Direct Coupling of Metal Carboxylate Salts with Ammonium Salts at Room Temperature

2021 ◽  
Author(s):  
Truong Thanh Tung ◽  
John Nielsen
Keyword(s):  
Room Temperature ◽  
Bond Formation ◽  
Direct Coupling ◽  
Ammonium Salts ◽  
Amide Bond ◽  
Metal Carboxylate ◽  
Amide Bond Formation ◽  
Simple Protocol

Herein, we report the green, expedite, and practically simple protocol for direct coupling of carboxylate salts and ammonium salts under ACN/H2O conditions at room temperature without the addition of tertiary...

Sign in / Sign up

Export Citation Format

Share Document