A Convenient Synthesis of 2-Substituted Thiazole-5-carboxylates

2004 ◽  
Vol 57 (6) ◽  
pp. 599 ◽  
Author(s):  
Mei Fong ◽  
Wit K. Janowski ◽  
Rolf H. Prager ◽  
Max R. Taylor
Keyword(s):  
Carboxylic Acid ◽  
Crystal Structures ◽  
Trifluoroacetic Acid ◽  
Fluoroacetic Acid ◽  
X Ray ◽  
Convenient Synthesis

The photolysis of ethyl 5-oxo-2-phenyl-2,5-dihydroisoxazole-4-carboxylate in acetonitrile containing 0.5% tri- fluoroacetic acid in the presence of thioamides gives moderate (40–60%) yields of thiazole-5-carboxylate esters. In the absence of trifluoroacetic acid, the intermediate vinyl thioesters can be isolated. That addition of the thioamide to the first formed carbene was, through sulfur, confirmed by X-ray crystal structures of 2-methylthiazole-5-carboxylic acid and a byproduct.

Hydrogen Bonds in "Carboxyoximes": the Case of Bomane Derivatives

2000 ◽  
Vol 55 (8) ◽  
pp. 677-684 ◽  
Author(s):  
Maciej Kubicki ◽  
Teresa Borowiak ◽  
Wiesław Z. Antkowiak
Keyword(s):  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Carboxylic Acids ◽  
Supramolecular Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carboxylic Groups ◽  
Acid Function

Abstract The tendency of forming mixed carboxyl-to-oxime hydrogen bonds was tested on the series of bornane derivatives: one with the acid function only (bornane-2-endo-carboxylic acid), one with the oxime function (2,2′-diethylthiobomane-3-oxime), and one with both oxime and carboxylic functions (bornane-2-oxime-3-endo-carboxylic acid). The crystal structures of these compounds were determined by means of X-ray diffraction. In bornane-2-endo-carboxylic acid and 2,2′-diethylthiobornane-3-oxime 'homogenic' hydrogen bonds were found, and these hydrogen bonds close eight-and six-membered rings, respectively. By contrast, in bornane-2-oxime-3-endo-carboxylic acid 'heterogenic' hydrogen bonds between carboxylic and oxime bonds were found. This carboxylic-oxime, or 'carboxyoxime' system is almost always present in compounds which have both oxime and carboxylic groups; therefore it can be regarded as an element of supramolecular structures (synthon). The presence of such synthons can break the tendency of carboxylic acids and oximes towards crystallizing in centrosymmetric structures.

Supramolecular architectures in two 1:1 cocrystals of 5-fluorouracil with 5-bromothiophene-2-carboxylic acid and thiophene-2-carboxylic acid

2017 ◽  
Vol 73 (6) ◽  
pp. 481-485 ◽  
Author(s):  
Marimuthu Mohana ◽  
Packianathan Thomas Muthiah ◽  
Colin D. McMillen
Keyword(s):  
Solid State ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Base Pairs ◽  
X Ray ◽  
Supramolecular Architectures ◽  
Acid Acid ◽  
Carboxylic Acid Dimer

In solid-state engineering, cocrystallization is a strategy actively pursued for pharmaceuticals. Two 1:1 cocrystals of 5-fluorouracil (5FU; systematic name: 5-fluoro-1,3-dihydropyrimidine-2,4-dione), namely 5-fluorouracil–5-bromothiophene-2-carboxylic acid (1/1), C5H3BrO2S·C4H3FN2O2, (I), and 5-fluorouracil–thiophene-2-carboxylic acid (1/1), C4H3FN2O2·C5H4O2S, (II), have been synthesized and characterized by single-crystal X-ray diffraction studies. In both cocrystals, carboxylic acid molecules are linked through an acid–acid R 2 2(8) homosynthon (O—H...O) to form a carboxylic acid dimer and 5FU molecules are connected through two types of base pairs [homosynthon, R 2 2(8) motif] via a pair of N—H...O hydrogen bonds. The crystal structures are further stabilized by C—H...O interactions in (II) and C—Br...O interactions in (I). In both crystal structures, π–π stacking and C—F...π interactions are also observed.

Inhibitors of the geotropic response in plants. The crystal structures of 2-[(Naphthalen-2-yl)carbamoyl]benzoic acid (β-Naptalam), 2-(Phenylcarbamoyl)-benzoic acid and 2-(5-Phenyl-1,3,4-oxadiazol-2-yl)benzoic acid

1983 ◽  
Vol 36 (12) ◽  
pp. 2455 ◽  
Author(s):  
G Smith ◽  
CHL Kennard ◽  
GF Katekar
Keyword(s):  
Hydrogen Bonding ◽  
Carboxylic Acid ◽  
Benzoic Acid ◽  
Crystal Structures ◽  
Carboxylic Acids ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carboxylic Acid Groups ◽  
Phthalamic Acid

The crystal structures of three geotropically active phthalamic acid derivatives have been determined by means of X-ray diffraction and the structural systematics for the series compared. The three acids are conformationally similar and, in contrast to the tendency among carboxylic acids to form hydrogen-bonded dimers, they exist as monomers with intermolecular hydrogen bonding between the carboxylic acid groups and the nitrogen or oxygen of the amide side chains.

Molecular Cocrystals of Carboxylic Acids. IX. Carboxylic Acid Interactions With Organic Heterocyclic Bases. The Crystal Structures of the Adducts of (2,4-Dichlorophenoxy)acetic Acid With 3-Hydroxypyridine, 2,4,6-Trinitrobenzoic Acid With 2-Aminopyrimidine, and 4-Nitrobenzoic Acid With 3-Amino-1,2,4-triazole

1992 ◽  
Vol 45 (6) ◽  
pp. 969 ◽  
Author(s):  
KA Byriel ◽  
CHL Kennard ◽  
DE Lynch ◽  
G Smith ◽  
JG Thompson
Keyword(s):  
Acetic Acid ◽  
Carboxylic Acid ◽  
Crystal Structures ◽  
Carboxylic Acids ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nitrobenzoic Acid ◽  
Dichlorophenoxy Acetic Acid ◽  
Heterocyclic Bases

The cocrystal adducts of a number of carboxylic acids with organic heterocyclic bases have been prepared, and their structures and intermolecular interactions interpreted through X-ray diffraction and infrared spectroscopic techniques. The crystal structures of three of these compounds, the 1 : 1 adducts [{(2,4-dich1orophenoxy)acetic acid)(3-hydroxypyridine)] (1), [(2,4,6-trinitrobenzoie acid)(2-aminopyrimidine)] (2), and [(4-nitrobenzoic acid)(3-amino- 1,2,4-trimole)] (3), have been determined by single-crystal X-ray diffraction and refined to residuals R 0.026, 0.033 and 0.040 for 1814, 1531 and 727 observed reflections, respectively.

Convenient Synthesis of New Heterocycles Containing the Quinoxaline Ring System

2020 ◽  
Vol 17 (2) ◽  
pp. 121-126
Author(s):  
Hanan A. Mohamed ◽  
Mohammad Hayal Alotaibi ◽  
Benson M. Kariuki ◽  
Gamal A. El-Hiti
Keyword(s):  
Crystal Structures ◽  
Ring System ◽  
Synthetic Methods ◽  
Spectroscopic Methods ◽  
X Ray ◽  
Convenient Synthesis ◽  
Current Article ◽  
New Compounds ◽  
Quinoxaline Ring

: The aim of the current article was to describe simple procedures for the synthesis of new heterocycles incorporating the quinoxaline moiety using benzene-1,2-diamine and quinoxaline-2,3- dithiol as precursors. Simple synthetic methods are described for the synthesis of new heterocycles using commercially available chemicals. Also, the new compounds were determined using analytical and spectroscopic methods including single X-ray crystal structures. A series of new heterocycles containing the quinoxaline nucleus have been synthesized in good yields using simple and convenient procedures. A process has been described for the synthesis of new heterocycles containing the quinoxaline moiety that might be difficult to synthesize by other routes.

Crystalline host-guest complexes involving carboxylic acid hosts and a dimethyl sulphoxide guest. X-ray crystal structures of two inclusion species

1995 ◽  
Vol 20 (3) ◽  
pp. 253-266 ◽  
Author(s):  
Ingeborg Cs�regh ◽  
Olga Gallardo ◽  
Edwin Weber ◽  
Rolf Pollex ◽  
Norbert D�rpinghaus
Keyword(s):  
Carboxylic Acid ◽  
Crystal Structures ◽  
Dimethyl Sulphoxide ◽  
X Ray

Solvates of selected fenamic acids with substituted pyridines: structure, thermal stability and desolvation

2016 ◽  
Vol 72 (6) ◽  
pp. 836-845 ◽  
Author(s):  
Jacky S. Bouanga Boudiombo ◽  
Ayesha Jacobs
Keyword(s):  
Thermal Stability ◽  
Carboxylic Acid ◽  
Crystal Structures ◽  
Mefenamic Acid ◽  
Tolfenamic Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Substituted Pyridines ◽  
Thermal Stability Of

Mefenamic acid (MA) formed solvates with 2-picoline (2PIC), 3-picoline (3PIC), 4-picoline (4PIC) and 3-chloropyridine (3CLPYR). The solvates crystallized in the space group P\bar 1 with the carboxylic acid of MA hydrogen-bonded to the nitrogen of the substituted pyridine. Tolfenamic acid (TFA) formed solvates with 2PIC and 3PIC, the crystal structures successfully solved in the space groupsP21/nandPbca, respectively. The fenamate conformation varied depending on the acid and the included solvent. Similarities were observed in the structures involving MA. The two solvate structures of TFA had different packing arrangements. Grinding and slurry experiments were also successful for the preparation of all of the compounds except MA·2PIC. Recrystallization, grinding and slurry investigations of MA and 2PIC yielded a polymorph; the structure was successfully solved inP21/n. Additionally, the thermal stability of the solvates was determined. Desolvation experiments were also performed and the resultant powders were analysed using powder X-ray diffraction.

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