scholarly journals Derivatives of the triaminoguanidinium ion, 5. Acylation of triaminoguanidines leading to symmetrical tris(acylamino)guanidines and mesoionic 1,2,4-triazolium-3-aminides

2017 ◽  
Vol 13 ◽  
pp. 579-588 ◽  
Author(s):  
Jan Szabo ◽  
Julian Greiner ◽  
Gerhard Maas
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Nitrogen Atom ◽  
Catalytic Hydrogenation ◽  
Acid Chlorides ◽  
Reaction Conditions ◽  
Derivatives Of ◽  
Guanidinium Salts ◽  
Triazolium Salts

Depending on the reaction conditions, N,N’,N’’-tris(benzylamino)guanidinium salts can react with carboxylic acid chlorides to form either symmetrical N,N’,N’’-tris(N-acyl-N-benzylamido)guanidines 6 or mesoionic 4-amino-1,2,4-triazolium-3-hydrazinides 7. The latter were converted into 1,2,4-triazolium salts by protonation or methylation at the hydrazinide nitrogen atom. Neutral 1,2,4-triazoles 10 were obtained by catalytic hydrogenation of an N-benzyl derivative. Crystal structure analyses of a 4-benzylamino-1,2,4-triazolium-3-hydrazinide and of two derived 1,2,4-triazolium salts are presented.

scholarly journals Synthetic Studies on Potent Marine Drugs: Synthesis and the Crystal Structure of 6-tert-butyl-4-phenyl-4H-chromene-2-carboxylic Acid

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hui-Jing Li ◽  
Jun-Li Wang ◽  
Rui Wang ◽  
Dong-Hui Luo ◽  
Yan-Chao Wu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Methyl Ester ◽  
Crystallographic Analysis ◽  
Antitumor Antibiotic ◽  
Stacking Interactions ◽  
X Ray ◽  
Structural Activity Relationship ◽  
Derivatives Of

4H-Chromene-2-carboxylic acid ester derivatives of renieramycin M might be of use for the structural-activity relationship studies of antitumor antibiotic tetrahydroisoquinoline natural products. Accordingly, 6-tert-butyl-4-phenyl-4H-chromene-2-carboxylic acid, one key intermediate, was synthesized via the condensation of (3E)-2-oxo-4-phenylbut-3-enoate methyl ester with 4-tert-butylphenol in the presence of AuCl3/3AgOTf (5 mol%), followed by cyclodehydration and aqueous hydrolysis. The product was unambiguously shown to the 4H-chromene-2-carboxylic acid by spectroscopy and X-ray crystallographic analysis. A packing diagram of the crystal structure shows that aromaticπ-stacking interactions and O–H⋯O hydrogen bond stabilize the structure in the solid.

Carboxylic Acid Analogues of Fosmidomycin

2003 ◽  
Vol 58 (5) ◽  
pp. 457-461 ◽  
Author(s):  
Thomas Kurz ◽  
Detlef Geffken ◽  
Claudia Wackendorff
Keyword(s):  
Carboxylic Acid ◽  
Acetic Anhydride ◽  
Formic Acid ◽  
Butyric Acid ◽  
Catalytic Hydrogenation ◽  
Methylene Chloride ◽  
Benzyl Ester ◽  
Acid Chlorides ◽  
Chloride Treatment

N-Alkylation of N-Boc-O-benzylhydroxylamine (1) with benzyl 4-bromobutyrate (2) in DMF gave N,O-bisprotected benzyl 4-hydroxyamino-butyrate (3), which was converted into 4-benzyloxyamino-butyric acid benzyl ester (4) with TFA in methylene chloride. Treatment of 4 with formic acid/acetic anhydride or various acid chlorides followed by catalytic hydrogenation led to 4-(N-acyl-N-hydroxyamino)-butyric acids 6.

Synthesis, X-ray Crystal Structure and Antiestrogenic Activity of 17-Methyl-16,17-secoestra-1,3,5(10)-triene Derivatives

2005 ◽  
Vol 70 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Marija N. Sakač ◽  
Dušan A. Miljković ◽  
Katarina M. Penov Gaši ◽  
Mirjana Popsavin ◽  
Olivera R. Klisurić ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structural Analysis ◽  
Sodium Borohydride ◽  
Catalytic Hydrogenation ◽  
Chiral Center ◽  
Reaction Conditions ◽  
X Ray ◽  
Antiestrogenic Activity ◽  
Biological Tests

Starting from 3-(benzyloxy)-16-(hydroxyimino)-estra-1,3,5(10)-trien-17-one (1) several 17-methyl-16,17-secoestratriene derivatives were synthesized. In the first step of synthesis, hydroxyimino ketone 1 was transformed into 3-(benzyloxy)-16-(hydroxyimino)-17α-methylestra-1,3,5(10)-trien-17β-ol (2), the Beckmann fragmentation of which gave 3-(benzyloxy)-17-methyl-17-oxo-16,17-secoestra-1,3,5(10)-triene-16-nitrile (3a). Reduction of 3a with sodium borohydride yielded (17S)-3-(benzyloxy)-17-hydroxy-17-methyl-16,17-secoestra-1,3,5(10)-triene-16-nitrile (4a), whose configuration at the newly formed chiral center was established by X-ray structural analysis. Catalytic hydrogenation of compound 3a under different reaction conditions yielded 3-hydroxy-17-methyl-17-oxo-16,17-secoestra-1,3,5(10)-triene-16-nitrile (3b) and 16-amino-17-methyl-16,17-secoestra-1,3,5(10)-triene-3,17-diol (6b). Biological tests in vivo of compounds 3b and 6b showed their moderate antiestrogenic activity.

Ketones from Nickel-Catalyzed Decarboxylative, Non-Symmetric Cross-Electrophile Coupling of Carboxylic Acid Esters

2019 ◽  
Author(s):  
Jiang Wang ◽  
Brian P. Cary ◽  
Peyton Beyer ◽  
Samuel H. Gellman ◽  
Daniel Weix
Keyword(s):  
Carboxylic Acid ◽  
Solid Support ◽  
Reaction Conditions ◽  
Decarboxylative Coupling ◽  
New Strategy ◽  
The Cross ◽  
Acyl Donors ◽  
Acid Esters

A new strategy for the synthesis of ketones is presented based upon the decarboxylative coupling of N-hydroxyphthalimide (NHP) esters with S-2-pyridyl thioesters. The reactions are selective for the cross-coupled product because NHP esters act as radical donors and the thioesters act as acyl donors. The reaction conditions are general and mild, with over 40 examples presented, including larger fragments and the 20-mer peptide Exendin(9-39) on solid support.

Cleavage of the Epimines of 1,6-Anhydrohexoses with Fluoride Anion

2005 ◽  
Vol 70 (12) ◽  
pp. 2075-2085 ◽  
Author(s):  
Jiří Kroutil ◽  
Klára Jeništová
Keyword(s):  
Fluoride Anion ◽  
Ring Cleavage ◽  
Protecting Group ◽  
Reaction Conditions ◽  
Aziridine Ring ◽  
Cleavage Reactions ◽  
Derivatives Of ◽  
Fluoro Derivatives

Aziridine ring cleavage reactions of five N-nosylepimines (2-6) having D-talo, D-galacto, D-manno, and D-allo configurations with potassium hydrogendifluoride under various reaction conditions have been performed. The cleavage regioselectively afforded diaxial isomers of vicinal amino-fluoro derivatives of 1,6-anhydro-β-D-gluco- and mannopyranose 7-11 in 51-94% yields. Removal of 2-nitrobenzenesulfonyl protecting group with benzenethiol has been attempted in the case of compound 10.

Crystal structure of tofacitinib dihydrogen citrate (Xeljanz®), (C16H21N6O)(H2C6H5O7)

2021 ◽  
pp. 1-8
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Density Functional ◽  
Acid Group ◽  
Dimensional Network ◽  
Van Der Waals Contacts ◽  
Citrate Anion

The crystal structure of tofacitinib dihydrogen citrate (tofacitinib citrate) has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Tofacitinib dihydrogen citrate crystallizes in space group P212121 (#19) with a = 5.91113(1), b = 12.93131(3), c = 30.43499(7) Å, V = 2326.411(6) Å3, and Z = 4. The crystal structure consists of corrugated layers perpendicular to the c-axis. Within the layers, cation⋯anion and anion⋯anion hydrogen bonds link the fragments into a two-dimensional network parallel to the ab-plane. Between the layers, there are only van der Waals contacts. A terminal carboxylic acid group in the citrate anion forms a strong charge-assisted hydrogen bond to the ionized central carboxylate group. The other carboxylic acid acts as a donor to the carbonyl group of the cation. The citrate hydroxy group forms an intramolecular charge-assisted hydrogen bond to the ionized central carboxylate. Two protonated nitrogen atoms in the cation act as donors to the ionized central carboxylate of the anion. These hydrogen bonds form a ring with the graph set symbol R2,2(8). The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

Orthoamide und Iminiumsalze, IC. Synthese und Reaktionen von N,N,N′,N′,N′′-Pentaalkyl-N′′-[2-(N,N,N′,N′,N′′-pentaalkylguanidinio)ethyl]-guanidiniumsalzen

2020 ◽  
Vol 75 (6-7) ◽  
pp. 685-695
Author(s):  
Willi Kantlehner ◽  
Ioannis Tiritiris ◽  
Wolfgang Frey ◽  
Ralf Kreß
Keyword(s):  
Crystal Structure ◽  
Guanidinium Salt ◽  
Guanidinium Salts

AbstractBis[bis(dibutylamino)methylen]hydrazine 8 is prepared from N,N,N′,N′-tetrabutylchloroformamidinium chloride (4c) and hydrazine. Bromine transforms 8 to the heterocyclic guanidinium salt 15a which is isolated as tetraphenylborate. From N,N,N′,N′-tetraalkylchloroformamidiniumchlorides and ethylendiamine the diguanidines are prepared which are alkylated to give diguanidinium salts, From these salts guanidinium salts can be prepared by anion metathesis with tetraphenylborate-, iodide-, hexafluorphosphate-, trifluoromethansulfonat-, bis(trifluormethansulfonyl)imide and tricyanmethanide as counteranions. The structure of the compounds 15 and 17b is confirmed by crystal structure analyses.

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