Synthesis and Crystal Structure of Ethyl 2-(benzo[d]oxazol-2-yl)-5-oxo-3-(o-tolylamino)- 2,5-dihydroisoxazole-4-carboxylate

The titlecompoundethyl 2-(benzo[d]oxazol-2-yl)-5-oxo-3-(o-tolylamino)-2,5-dihydroisoxazole-4-carboxylate (5) was synthesized and studied by the single crystal X-ray diffraction method. Its structure was confirmed by IR, 1H and 13C NMR spectroscopy, microanalyses, and X-ray single crystal structure determination. Compound 5 crystallized in the monoclinic system, space group P21/c, a=11.9936(3) Å, b=13.9638(3) Å, c=11.5126(4) Å,α=γ=90 °,β =108.939(3) °, V=1823.70(9)Å3,Z=4, R1=0.050 and wR2 = 0.130. Compound 5 shows an intramolecular hydrogen bond between N9–H...O3 atoms. The H-bond and donor–acceptor (N9...O3) distances were obtained 2.165 and 2.798 Å, respectively. The crystal structure of 5 also shows a weak interaction between O1 and O26 atoms with distance of 2.985 Å. The benzo[d]oxazole and o-toluidine rings moieties are not collimated together on isoxazolone ring. The torsion angles of N9–C8–N7–C17, O6–N7–C17–O18 equal –49.63 ° and 68.67 °, respectively.KEYWORDS Isoxazolone; 2-chlorobenzoxazole; N-substituted isoxazolone; single crystal X-ray structure; hydrogen bond

A Simple Three-component Synthesis of 3-Amino-5-arylpyridazine-4-carbonitriles

New 3-amino-5-arylpyridazine-4-carbonitriles have been synthesized by a one-pot three-component reaction of malononitrile with arylglyoxals in the presence of hydrazine hydrate at room temperature in water and ethanol.KEYWORDS Arylglyoxals, arylpyridazines, hydrazine hydrate, one-pot, malononitrile

Selective Bromination of 4-Chloro-1-indanone and Synthesis of (4-Chloro-2, 3-Dihydro-1H-indene-2-yl)methanamine

The synthesis of 4-chloro-1-indanone in four steps from 2-chlorobenzaldehyde was investigated. Bromination of this compound under various conditions occurred in the cyclopentanone ring, producing mono- and dibromo derivatives. Cyanation of 2-bromo-4-chloro-1-indanone followed by reduction gave (4-chloro-2, 3-dihydro-1H-indene-2-yl)methanamine in quantitative yield.Keywords: Indanone, Bromination, Cyanation, Reduction, GABAB receptor

Synthesis of 9H-Indeno [1, 2-b] Pyrazine and 11H-Indeno [1, 2-b] Quinoxaline Derivatives in One-step Reaction from 2-Bromo-4-chloro-1-indanone

The reaction of 2-bromo-4-chloro-1-indanone with 2,3-diaminomaleonitrile, benzene-1,2-diamine and 4-methylbenzene-1,2-diamine in glacial acetic acid gave 8-chloro-9H-indeno[1,2-b]pyrazine-2,3-dicarbonitrile, 1-chloro-11H-indeno[1,2-b]quinoxaline and 1-chloro-7-methyl-11H-indeno[1,2-b]quinoxaline, respectively, in good yield.Keywords: 2-bromo-4-chloro-1-indanone, diaminopyridine, indeno[1,2-b]quinoxaline, indeno[1,2-b]pyrazine, debrominatio

Synthesis of bis-quinoxaline derivatives using Tonsil clay as a catalyst

A convenient and efficient synthesis of new bis-quinoxaline is described, involving condensation of 1,2-diamines with 9-ethyl-3,6-di(1,2-dioxoethyl)carbazole in the presence of Tonsil clay, a readily  available and inexpensive catalyst. The structures of all new products were identified by 1H-NMR, 13C-NMR and FT-IR spectral data and microanalysis. KEY WORDS: bis-Quinoxaline, bis-Glyoxal, Green chemistry, 1,2-Diamine, Tonsil clay Bull. Chem. Soc. Ethiop. 2016, 30(1), 129-136.DOI: http://dx.doi.org/10.4314/bcse.v30i1.1

Synthesis of 2-(5-Nitropyrid-2-yl)-3-(4-substitutedphenyl)aminoisoxazol-5(2H)-ones and Their Rearrangements to Imidazo[1,2-a]- pyridines and Indoles with Triethylamine

3-(4-Substitutedphenyl)aminoisoxazol-5(2H)-ones, substituted on nitrogen with a nitropyridine group, react with triethylamine to give imidazo[1,2-a]pyridines and indoles. With 4-bromophenyl and 4-methylphenyl group substituents only imidazopyridines are formed, but the 4-methoxyphenyl derivative gave a 3:1 mixture of the corresponding imidazo[1,2-a]pyridine and 2-pyridylaminoindole, respectively

The synthesis of almazoles A and B

Almazoles A (1) and B (2) are formed in seven steps from phenylalanine without any racemization. The key step is the N-acylation of the isoxazol-5(2H)-one (5) with the phthalimide-protected amino acid, and photolysis of the product at 300 nm in acetone

A new synthesis of chiral aminoalkyloxazolecarboxylate esters from isoxazol-5(2H)-ones: the synthesis of almazoles A and B

2-(1-Aminoalkyl)oxazole-4 and 5-carboxylates are available, without detectable racemisation, by a sequence involving N-acylation of isoxazol-5(2H)one carboxylates with phthalimidoamino acids, photolysis of the acylated product, and hydrazinolysis. An application of the procedure to the synthesis of almazole A and B is described (C) 1998 Elsevier Science Ltd. All rights reserved

Synthesis and biological activity of allosteric modulators of GABA B receptors part 3.3-(2,6-bis-iso-propyl-4-hydroxyphenyl)propanols

Printed in Brazil - ©2007 Sociedade Brasileira de QuímicaA series of six 2,2-disubstituted 3-[3,5-di-iso-propyl-4-hydroxyphenyl] propan-1-ol derivatives have been prepared for evaluation as allosteric modulators of GABAB receptors. The activity (EC50 30 μM) was greatest for the dimethyl analogue, but the isopropylphenyl compounds were generally weaker than the corresponding t-butyl compounds. Methylation of the phenolic group led to loss of activity. ©2007 Sociedade Brasileira de Química.David I. B. Kerr, Jabbar Khalafy,Jennifer Ong, Rolf H. Prager and Mehdi Rima

[1,5] and [1,2] acetyl shifts in Diels-Alder adducts of 2-acetyl-6-methyl-l,4-benzoquinone

Treatment of the Diels-Alder adduct 4a-acetyl-4a, 5, 8, 8a-tetrahydro-3-methyl-I, 4 naphthoquinone with pyridine-methanol or acetic anhydride leads to a [I, 5J acetyl shift to the 3-position which can be followed by a [1,2J acetyl shift to the 2-position (adduct numbering)