Tag: 0-100

Replacement of oxygen by sulfur in small organic molecules. 3. Theoretical studies on the tautomeric equilibria of the 2OH and 4OH-substituted oxazole and thiazole and the 3OH and 4OH-substituted isoxazole and isothiazole in the isolated state and in solution was written by Nagy, Peter I.. And the article was included in International Journal of Molecular Sciences in 2016.SDS of cas: 80348-66-9 The following contents are mentioned in the article:

This follow-up paper completes the author’s investigations to explore the in-solution structural preferences and relative free energies of all OH-substituted oxazole, thiazole, isoxazole, and isothiazole systems. The polarizable continuum dielec. solvent method calculations in the integral-equation formalism (IEF-PCM) were performed at the DFT/B97D/aug-cc-pv(q+(d))z level for the stable neutral tautomers with geometries optimized in dichloromethane and aqueous solution With the exception of the predictions for the predominant tautomers of the 3OH isoxazole and isothiazole, the results of the IEF-PCM calculations for identifying the most stable tautomer of the given species in the two selected solvents agreed with those from exptl. investigations. The calculations predict that the hydroxy proton, with the exception for the 4OH isoxazole and 4OH isothiazole, moves preferentially to the ring nitrogen or to a ring carbon atom in parallel with the development of a C=O group. The remaining, low-fraction OH tautomers will not be observable in the equilibrium compositions Relative solvation free energies obtained by the free energy perturbation method implemented in Monte Carlo simulations are in moderate accord with the IEF-PCM results, but consideration of the ΔGsolv/MC values in calculating ΔGstot maintains the tautomeric preferences. It was revealed from the Monte Carlo solution structure analyses that the S atom is not a hydrogen-bond acceptor in any OH-substituted thiazole or isothiazole, and the OH-substituted isoxazole and oxazole ring oxygens may act as a weak hydrogen-bond acceptor at most. The mols. form 1.0-3.4 solute-water hydrogen bonds in generally unexplored numbers at some specific solute sites. Nonetheless, hydrogen-bond formation is favorable with the NH, C=O and OH groups. This study involved multiple reactions and reactants, such as Isoxazol-4-ol (cas: 80348-66-9SDS of cas: 80348-66-9).

Isoxazol-4-ol (cas: 80348-66-9) belongs to isoxazole derivatives. Isoxazoles also form the basis for a number of drugs, including the COX-2 inhibitor valdecoxib (Bextra) and a neurotransmitter agonist AMPA. Isoxazole can be synthesised via a variety of methods. Examples include via the reaction of hydroxylamine with 1,3-diketones or derivatives of propiolic acid.SDS of cas: 80348-66-9

Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem

Reaction between dimethyloxosulfonium methylide and benzonitrile oxide was written by Umani-Ronchi, A.;Bravo, P.;Gaudiano, G.. And the article was included in Tetrahedron Letters in 1966.SDS of cas: 80348-66-9 The following contents are mentioned in the article:

The reactivity of H₂C^–S⁺(O)Me₂ (I) towards 1,3-dipoles was investigated to test the possibility of obtaining 4-membered heterocyclic rings. (I prepared in situ from Me₃S(O)I or Me₃S(O)Cl and NaH) treated with PhCNO in cold Me₂SO gave a complex mixture from which 3-phenyl-2-isoxazoline (II), Ph vinyl ketone oxime (III), 3-phenyl-5-benzoyl-2-isoxazoline oxime (IV) and the Ph vinyl ketone oxime hydroxamie ester (V) were isolated. None of the unstable 3-phenyloxazetidine (VI) was isolated. The ylide brought about 2 consecutive transfers of CH₂ to the substrate, probably through the zwitterion intermediate (VII) from which the compounds II-V may be readily derived. II was identified by anal., N.M.R. spectrum, and physicochem. characteristics. Addition of 2 molar equivalents I per molar equivalent PhNCO yielded up to 30% III, m. 85°, evidently the syn-Ph isomer. IV, m. 136°, was prepared by reaction of III with PhCNO. V, m. 126°, was also obtained in very small amount in the reaction of PhCNO with III. Beside the compounds II-V, many byproducts were obtained in small amounts PhCN, BzNH₂ and BzOH originated from PhCNO by reductive and hydrolytic processes. The diphenylfuroxan (VIII) is a normal product of dimerization; BzNHOBz is a decomposition product of PhC(:NOH)Cl as well as of PhCNO itself under acid conditions: and the diphenyl-1,2,4-oxadiazole (IX) represents the product of the reaction between PhCNO and PhCN (CA 51, 15502e) according to Leandri and Pellotti. This study involved multiple reactions and reactants, such as Isoxazol-4-ol (cas: 80348-66-9SDS of cas: 80348-66-9).

Isoxazol-4-ol (cas: 80348-66-9) belongs to isoxazole derivatives. Isoxazoles are aromatic heterocycles containing an N–O bond. Isoxazoles are commonly used as enaminoketone or β-diketone surrogate. The electrophilic cyclization of various 2-alkynone O-methyl oximes with a wide range of substrates such as ICl, I2, Br2, PhSeBr, etc. provides a variety of 3,4,5-trisubstituted isoxazoles in good to excellent yields.SDS of cas: 80348-66-9

Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem

4-Isoxazolones was written by Cabiddu, Salvatore;Ricca, Aldo. And the article was included in Atti della Accademia Nazionale dei Lincei, Classe di Scienze Fisiche, Matematiche e Naturali, Rendiconti in 1966.HPLC of Formula: 80348-66-9 The following contents are mentioned in the article:

An attempt to extend the reaction used by Blatt and Hawkins (CA 29, 159¹) for the synthesis of 4-isoxazoles is described. The compounds were synthesized by the following route: RCOCH₂COR SO₂Cl₂→ RCOCHClCOR¹ AcON₂→ RCOCH(OAc)COR¹ (I) NH₂OH→ RC(:NOH)C(OAc):C(OH)R¹ (II) → III. By this method the following III were obtained (R, R¹, and m.p. and b.p./mm. of the Me ether given): Ph, Ph, 105 and 125°, -; Me, Me, 92-4 and 83°, 95-100°/12; Et, Et, b_0.2 87-90°, 60-4°/30; Ph, Me, 11819°, 120°/0.5. The di-Ph and di-Me derivatives were obtained in 2 polymorphic forms. The treatment of II with NH₂OH in a neutral medium permitted isolation of PhC(:NOH)CH(Oll)COMe and PhC(:NOH)CH(OH)COPh, m. 156-8°, in 84% yield, which upon acidification were immediately cyclized to the corresponding III. By the action of NH₂OH on acetylacetonate in the presence of pyridine, the dioxime MeC(:NOH)CH(OAc)C(:NOH)Me, m. 157°, was obtained, which upon acid treatment underwent cyclization to give 3,5-dimethyl-4-isoxazole. All synthesized isoxazoles were sensitive to light and tended to be unstable on storage. All except the 3,5-di-Ph compound gave enolic reactions with FeCl₃. This study involved multiple reactions and reactants, such as Isoxazol-4-ol (cas: 80348-66-9HPLC of Formula: 80348-66-9).

Isoxazol-4-ol (cas: 80348-66-9) belongs to isoxazole derivatives. An isoxazolyl group is found in many beta-lactamase-resistant antibiotics, such as cloxacillin, dicloxacillin and flucloxacillin. Some alternative routes for the synthesis of isoxazoles have also been developed and reported. The 2-benzoyl-2-halo-2H-azirines provide 4-haloisoxazoles in good yields after heating in toluene at reflux temperature.HPLC of Formula: 80348-66-9

Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem

Gold(I)-Catalyzed Intramolecular S_EAr Reaction: Efficient Synthesis of Isoxazole-Containing Fused Heterocycles was written by Morita, Taiki;Fukuhara, Shintaro;Fuse, Shinichiro;Nakamura, Hiroyuki. And the article was included in Organic Letters in 2018.COA of Formula: C3H3NO2 The following contents are mentioned in the article:

Intramol. electrophilic aromatic substitution (S_EAr) reaction at the 5-position of isoxazoles was achieved. The electron-donating heteroatoms (N and O) at the 4-position of isoxazoles, which can be readily prepared based on our originally developed synthetic procedure, and a cationic gold(I) catalyst are essential for the intramol. S_EAr reaction to synthesize isoxazole-containing fused heterocycles. Structurally diverse isoxazolopyridines I (R¹ = H, 4-MeC₆H₄, 4-ClC₆H₄, n-pentyl; R² = Me, n-pentyl, t-Bu, Ph, 4-MeC₆H₄, etc.; R³ = H, Me) and isoxazolopyrans II (R¹ = H, Ph, 4-ClC₆H₄, n-pentyl, etc.; R² = Me, H, cyclopentyl, Ph, etc.), including base-labile 3-unsubstituted derivatives, were synthesized in good to high yields. The addition of N-phenylbenzaldimine as a hydrogen acceptor improved yields in the synthesis of isoxazolopyridines. Furthermore, synthesis of the tetracyclic fused ring system was achieved by tandem cyclization from the corresponding diyne. This study involved multiple reactions and reactants, such as Isoxazol-4-ol (cas: 80348-66-9COA of Formula: C3H3NO2).

Isoxazol-4-ol (cas: 80348-66-9) belongs to isoxazole derivatives. Isoxazoles are aromatic heterocycles containing an N–O bond. The weakness of this bond allows the ring opening of these heterocycles under reductive conditions. The most common methods for N–O bond cleavage in isoxazoles are hydrogenation with palladium or platinum catalysts or with Raney Ni. Recent developments have shown that Mo(CO)6 efficiently cleaves the N–O bond in isoxazoles.COA of Formula: C3H3NO2

Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem

A theoretical treatment of solvent effects on the tautomeric equilibria of five-membered rings with two heteroatoms was written by Karel’son, M. M.;Katritzky, Alan R.;Szafran, Miroslaw;Zerner, Michael C.. And the article was included in Journal of the Chemical Society in 1990.COA of Formula: C3H3NO2 The following contents are mentioned in the article:

The tautomeric equilibrium constants of nine oxo and hydroxy derivatives of five-membered heterocycles containing two ring heteroatoms (nitrogen or oxygen) as calculated by the AM1 quantum chem. model agree well with literature gas-phase data. The inclusion of solvent effects through a self-consistent reaction field technique into these calculations yields results in full agreement with exptl. data obtained for these systems in aqueous solution It is not possible to use the calculated energies for isolated mols. to predict the relative stabilities of these tautomers in solution Solvent effects are specific, and differentially lower the energy of one tautomer over another demonstrating in some cases a strong solvent effect on tautomeric equilibrium In general, dielec. media favor charge separation and preferentially lower the energy of species with the greater degree of charge separation In the species studied solvent reaction field effects favor ionic resonance forms of the carbonyl tautomers and hence a greater degree of aromaticity. This study involved multiple reactions and reactants, such as Isoxazol-4-ol (cas: 80348-66-9COA of Formula: C3H3NO2).

Isoxazol-4-ol (cas: 80348-66-9) belongs to isoxazole derivatives. Isoxazoles also form the basis for a number of drugs, including the COX-2 inhibitor valdecoxib (Bextra) and a neurotransmitter agonist AMPA. Isoxazole can be synthesised via a variety of methods. Examples include via a 1,3-dipolar cycloaddition of nitrile oxides with alkynes.COA of Formula: C3H3NO2

Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem

Cycloserine and related compounds. XI. 4-Hydroxy-3^– isoxazolidone and some of its derivatives was written by Khomutov, R. M.;Karpeiskii, M. Ya.;Chang, Chih-P’ing;Kochetkov, N. K.. And the article was included in Zhurnal Obshchei Khimii in 1960.HPLC of Formula: 80348-66-9 The following contents are mentioned in the article:

cf. CA 53, 9186e; 54, 21046c. Addition of 6.1 g. HONH₂.H₂SO₄ at -5° to 6.8 g. NaOH in H₂O, followed by 6.1 g. Me chloropropionate and stirring 4 hrs. finally at 20°, gave after standing 12 hrs. and treatment with MeOH, an unstated yield of 3-isoxazolidone isolated as Na salt hemihydrate decomposing 68°; monohydrate decomposed 61-2°. This with H₂SO₄ in MeOH gave 3-isoxazolidone decomposed 69-70°. Similarly were prepared: 4-hydroxy-3-isoxazolidone (I) m. 77° (Na salt decomposed 60-4°); 4-methoxy-3-isoxazolidone decomposed 78-9° (Na salt decomposed 65-8°); 4-ethoxy analog Na salt decomposed 68°; 4-acetoxy-3-isoxazolidone decomposed 91-2°. I hydrogenated over Pt in MeOH to glyceramide m. 91°. Keeping I in MeOH-dry HCl 24 hrs. gave glyceramide. Paper chromatographic R_f values for the products were determined This study involved multiple reactions and reactants, such as Isoxazol-4-ol (cas: 80348-66-9HPLC of Formula: 80348-66-9).

Isoxazol-4-ol (cas: 80348-66-9) belongs to isoxazole derivatives. Isoxazoles are aromatic heterocycles containing an N–O bond. The weakness of this bond allows the ring opening of these heterocycles under reductive conditions. Some alternative routes for the synthesis of isoxazoles have also been developed and reported. The 2-benzoyl-2-halo-2H-azirines provide 4-haloisoxazoles in good yields after heating in toluene at reflux temperature.HPLC of Formula: 80348-66-9

Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem

Generation of an 4-Isoxazolyl Anion Species: Facile Access to Multifunctionalized Isoxazoles was written by Morita, Taiki;Fuse, Shinichiro;Nakamura, Hiroyuki. And the article was included in Angewandte Chemie, International Edition in 2016.Name: Isoxazol-4-ol The following contents are mentioned in the article:

A direct functionalization of unsubstituted isoxazole was achieved by generation of 4-isoxazolyl anion species I. An efficient 4-iodination of isoxazole and halogen-metal exchange reaction using a turbo Grignard reagent (iPrMgCl·LiCl) were essential for the generation of I, which reacted with various electrophiles to give 4-functionalized isoxazoles in good to high yields. Isoxazolyl boronate, boronic acid, and stannane were also synthesized as useful building blocks from unsubstituted isoxazole. The current methods enabled us to synthesize multi-functionalized isoxazoles by introducing each substituent into the desired positions. Furthermore, total synthesis of triumferol, which was isolated from Triumfetta rhomboidea, was achieved from unsubstituted isoxazole in only three steps. This study involved multiple reactions and reactants, such as Isoxazol-4-ol (cas: 80348-66-9Name: Isoxazol-4-ol).

Isoxazol-4-ol (cas: 80348-66-9) belongs to isoxazole derivatives. Isoxazoles are aromatic heterocycles containing an N–O bond. Isoxazoles are commonly used as enaminoketone or β-diketone surrogate. As with isoxazolines, isoxazoles may be cleaved using low-valent titanium obtained from the Kulinkovich reaction.This procedure affords enaminoketones from 2,4-substituted isoxazoles.Name: Isoxazol-4-ol

Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem

Heterocyclic analogs of phenol as novel potential antioxidants was written by Shi, Jing;Liang, Shuang;Feng, Ye-Su;Wang, Hua-Jing;Guo, Qing-Xiang. And the article was included in Journal of Physical Organic Chemistry in 2009.Product Details of 80348-66-9 The following contents are mentioned in the article:

Five d. functional theory (DFT) methods including B3LYP, B3PW91, MPW1K, MPWB, TPSS1KCIS were evaluated by comparing with the exptl. O[bond]H bond dissociation enthalpies (BDEs) of substituted phenols. B3PW91 is the best method, for which the calculation error was 3.62 kJ/mol. Subsequently, the BDEs (O[bond]H) of hydroxyl groups on five- and six-membered heteroat. aromatic rings were calculated using the (RO)B3PW91/6-311++G(2df,2p)//(U)B3LYP/6-311g(d,p) procedure. The ionization energy (IE) and proton affinity [PA(O^–)] of these compounds also were examined From theor. study, imidazolols, thiazolols, and oxazolols were studied to assess their antioxidant activities. 5-Oxazolol could be a promising novel antioxidant precursor. Copyright © 2009 John Wiley and Sons, Ltd. This study involved multiple reactions and reactants, such as Isoxazol-4-ol (cas: 80348-66-9Product Details of 80348-66-9).

Isoxazol-4-ol (cas: 80348-66-9) belongs to isoxazole derivatives.Synthetically, isoxazoles serve as valuable precursors for the construction of diverse molecules, including many natural products. Fe(CO)5 efficiently cleaves the N–O bond of fused isoxazolo-1,4-quinones to give the corresponding imines.All the common reducing reagents failed to open the isoxazole ring.Product Details of 80348-66-9

Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem

Isolation, structure, and synthesis of 4-hydroxyisoxazole (triumferol), a seed germination inhibitor from an African plant was written by Kusumi, Takenori;Chang, Conway C.;Wheeler, Margaret;Kubo, Isao;Nakanishi, Koji;Naoki, Hideo. And the article was included in Tetrahedron Letters in 1981.Application In Synthesis of Isoxazol-4-ol The following contents are mentioned in the article:

Triumferol (I; R = OH) (II) was isolated from Triumfetta rhomboidea, and its structure was determined by standard spectral methods. II had antigermination activity against lettuce seeds (100% at 100 ppm, 70% at 50 ppm). II was prepared from I (R = CO₂H) by sequential chlorination (PCl₅), Grignard reaction with MeBr, and oxidative cleavage (H₂O₂, H₂SO₄, CH₂Cl₂, reflux). This study involved multiple reactions and reactants, such as Isoxazol-4-ol (cas: 80348-66-9Application In Synthesis of Isoxazol-4-ol).

Isoxazol-4-ol (cas: 80348-66-9) belongs to isoxazole derivatives. An isoxazolyl group is found in many beta-lactamase-resistant antibiotics, such as cloxacillin, dicloxacillin and flucloxacillin. Isoxazole can be synthesised via a variety of methods. Examples include via a 1,3-dipolar cycloaddition of nitrile oxides with alkynes.Application In Synthesis of Isoxazol-4-ol

Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem