Category: oxazolidine

Brown, Desmond J. published the artcileSpectra, ionization, and deuteration of oxazoles and related compounds, HPLC of Formula: 20662-83-3, the publication is Journal of the Chemical Society [Section] B: Physical Organic (1969), 270-6, database is CAplus.

The 1H N.M.R. spectra of oxazole, its derivatives and some related compounds in nonpolar, polar, and protonating media are discussed. The pKa values for oxazole (0.8, measured by the chem. shifts of H-2 in acidic media) and its derivatives show that the nucleus is far less basic than previously supposed, primarily owing to the powerful inductive effect of the O atom. The uv spectra of 2,5- and 2,4-diphenyloxazole indicate through-conjugation only in the former. This fact and other data suggest that oxazoles should be considered more as conjugated dienes than as fully aromatic compounds The rates for the 2-deuteration of simple oxazoles increase with the alkalinity; oxazole also undergoes 5- but not 4-deuteration under extreme conditions. On these grounds, the electron-distribution of the 3 C atoms of oxazole is clearly in the order 4 > 5 > 2. This is confirmed by the chem. shifts of the resp. protons and the pKa values of 2-, 4-, and 5-carboxyoxazole. Isoxazole (pKa – 2.03) is a much weaker base than previously reported.

Journal of the Chemical Society [Section] B: Physical Organic published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, HPLC of Formula: 20662-83-3.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Bredereck, H. published the artcileA new synthesis of β-oxocarboxylic acid amides and substituted quinolines, Recommanded Product: 4,5-Dimethyloxazole, the publication is Angewandte Chemie (1959), 32, database is CAplus.

Molar amounts of POCl₃ produce a self-condensation of N,N-dimethylcarboxamides to β-oxo-N,N-dimethylcarboxamides which then react with aromatic amines and POCl₃ to yield substituted 2-dimethylaminoquinolines. Thus, from acetic, propionic, and butyric acid dimethylamides are obtained the corresponding α-acyl-N,N-dimethylcarboxamides. The acetylacetic acid dimethylamide and aniline give a moderate yield of 2-dimethylamino-4-methylquinoline, obtained in better yield starting from β-dimethylaminocrotonic acid N,N-dimethylamide.

Angewandte Chemie published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, Recommanded Product: 4,5-Dimethyloxazole.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Bredereck, Hellmut published the artcileRing cleavage of oxazoles with 2,4-dinitrophenylhydrazine, Synthetic Route of 20662-83-3, the publication is Chemische Berichte (1960), 2010-15, database is CAplus.

The ring cleavage of oxazoles with 2,4-(O₂N)₂C₆H₃NHNH₂ (I) to the osazones of glyoxal derivatives is described. BzCHBrMe (63 g.), 96 g. HCO₂NH₄, 390 g. HOC₂H, and 45 cc. Ac₂O refluxed 5 hrs. and distilled gave 24 g. 5-methyl-4-phenyloxazole (II), b₁₁ 122°, m. 1°, n²⁰_D 1.5723. BzCH(OH)Ph (53 g.), 225 g. HCONH₂, and 49 g. concentrated H₂SO₄ heated 1 hr. at 100-20° and 2 hrs. at 150° yielded 33.5 g. 4,5-diphenyloxazole (IIa), b_0.002 115°, m. 44°. BzCH₂Br (100 g.) and 50 g. AcNH₂ heated 2 hrs. at 120-40° gave 35 g. 2-methyl-4-phenyloxazole (III), b₁₁ 116°, m. 42.5°. The appropriate oxazole (about 1 g.) in 10 cc. MeOH and 600 cc. reagent solution (cold-saturated solution of I in 2N HCl) kept at room temperature and filtered, and the residue washed with 2N HCl and H₂O, dried, and recrystallized from HCONMe₂ gave the corresponding cleavage product. III gave (during 2 weeks) phenylglyoxal 2,4-dinitrophenylosazone (IV), m. 299-300°, and benzoylcarbinol 2,4-dinitrophenylosazone (V), m. 234-5°. 4-Phenyloxazole (VI) gave (during 6 weeks) IV and V. 2-Methyl-4-carbethoxyoxazole (VII) gave (during 2 days) Et α-acetamido-α-formylacetate 2,4-dinitrophenylhydrazone (VIII), m. 185-6° (EtOAc), and (during 12 days) VIII and [2,4-(O₂N)₂C₆H₃NHN: CH]₂ (IX), m. 328-30°. The appropriate oxazole (about 1 g.) refluxed with 400 cc. reagent solution (1% I in 2N HCl) and worked up in the usual manner gave the derivative of the cleavage product(s) in 75-95% yield. IIa gave [2,4-(O₂N)₂C₆H₃NHN:CPh]₂, m. 310-11° (decomposition), which was also obtained by refluxing 2 g. Bz₂, 5 g. I, and 400 cc. 6N HCl 10 hrs., and boiling the precipitate with 300 cc. EtOAc and recrystallizing it from HCONMe₂. 4,5-Dimethyloxazole, b₇₆₀ 128°, n²⁰_D 1.4281, and 2,4,5-trimethyloxazole, b₁₁ 43°, n²⁰_D 1.4270, yielded similarly [2,4-(O₂N)₂C₆H₃NHN:-CMe]₂, m. 330-3° (decomposition). II, 5-methyl-4-phenyloxazole, and 2,5-dimethyl-4-phenyloxazole gave methylphenylglyoxal 2,4-dinitrophenylosazone, m. 259°. VII gave IX, m. 328-30° (decomposition). III and VI yielded IV, m. 299-300°. 5-Ethyl-4-phenyloxazole and 2-methyl-5-ethyl-4-phenyloxazole yielded ethylphenylglyoxal 2,4-dinitrophenylosazone, m. 226°. 5-Propyl-4-phenyloxazole gave propylphenylglyoxal 2,4-dinitrophenylosazone, m. 244°. 4-Methyl-5-benzyl-, 2,4-dimethyl-5-benzyl-, and 2,5-dimethyl-4-benzyloxazole yielded methylbenzylglyoxal 2,4-dinitrophenylosazone, m. 264°. 4,5-Diethyloxazole, 2-methyl-4,5-diethyloxazole, b₃₀ 76°, n²⁰_D 1.4423, and 2,4,5-triethyloxazole, b₃₀ 85°, n²⁰_D 1.4494, gave [2,4-(O₂N)₂C₆H₃NHN:CEt]₂, m. 290-1°.

Chemische Berichte published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, Synthetic Route of 20662-83-3.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Murugesan, Natesan published the artcileBiphenylsulfonamide endothelin receptor antagonists: discovery of 4′-oxazolyl biphenylsulfonamides as a new class of potent, highly selective ET_A antagonists, Computed Properties of 72571-06-3, the publication is Journal of Medicinal Chemistry (2000), 43(16), 3111-3117, database is CAplus and MEDLINE.

The synthesis and structure-activity relationship (SAR) studies of a series of 4′-oxazolyl-N-(3,4-dimethyl-5-isoxazolyl)[1,1′-biphenyl]-2-sulfonamide derivatives as endothelin-A (ET_A) receptor antagonists are described. The data reveal a remarkable improvement in potency and metabolic stability when the 4′-position of the biphenylsulfonamide is substituted with an oxazole ring. Addnl. 2′-substitution of an acylaminomethyl group further increased the binding activity and provided one of the first subnanomolar ET_A-selective antagonists in the biphenylsulfonamide series (ET_A K_i = 0.2 nM). Among the compounds described, (N-(3,4-dimethyl-5-isoxazolyl)-4′-(2-oxazolyl)[1,1′-biphenyl]-2-sulfonamide; BMS-193884) had the optimum pharmacol. profile and was therefore selected as a clin. candidate for studies in congestive heart failure.

Journal of Medicinal Chemistry published new progress about 72571-06-3. 72571-06-3 belongs to oxazolidine, auxiliary class Oxazole,Bromide,Benzene, name is 5-(4-Bromophenyl)oxazole, and the molecular formula is C9H6BrNO, Computed Properties of 72571-06-3.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Hay, Duncan A. published the artcileA flexible synthesis of C-6 and N-1 analogues of a 4-amino-1,3-dihydroimidazo[4,5-c]pyridin-2-one core, Application In Synthesis of 20662-83-3, the publication is Tetrahedron Letters (2011), 52(44), 5728-5732, database is CAplus.

A flexible route which enables access to derivatives of 4-amino-1,3-dihydroimidazo[4,5-c]pyridin-2-ones is described. Issues of selectivity, reaction safety, and low yields in original routes are overcome with the key improvements to the route, including a Negishi cross-coupling and use of a carbamate as a protecting group and intrinsic carbonyl source. The new route enables variation of C-6 and N-1 substituents.

Tetrahedron Letters published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, Application In Synthesis of 20662-83-3.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Bogdanov, V. S. published the artcileCarbon-13, nitrogen-14, and proton NMR spectra and effects of substituents in oxazoles, Application In Synthesis of 20662-83-3, the publication is Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya (1980), 305-16, database is CAplus.

¹³C NMR data were obtained for 40 oxazoles; ¹H and ¹⁴N data were obtained for 6 and 11 of these, resp. The following linear correlations were made: chem. shift (δ) for C-2 with δ for C-4, δ for C-4 with δ for C-5, δ for C-2 with δ for H-2, δ for C-4 with δ for H-4, δ for C-5 with the electronegativity of the substituent at C-5, and ¹³C δ values for 4,5-disubstituted oxazole with those for 1,2-disubstituted benzenes. An additive method for calculating ¹³C δ values was tested successfully. The effect of substituents on various coupling constants was also determined

Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, Application In Synthesis of 20662-83-3.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Al-Duri, B. published the artcileSupercritical water oxidation (SCWO) for the removal of N-containing heterocyclic hydrocarbon wastes. Part I: Process enhancement by addition of isopropyl alcohol, Category: oxazolidine, the publication is Journal of Supercritical Fluids (2016), 155-163, database is CAplus.

The present work investigates the destruction of nitrogen-containing heterocyclic hydrocarbons frequently encountered in hazardous wastes by supercritical water oxidation (SCWO), with focus on the process enhancement using iso-Pr alc. (IPA) as co-fuel. 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) was selected for SCWO in a continuous plug flow reactor, under a range of temperatures (400-525°C), oxidant ratios nSR (0.8-2.0) and IPA/DBU ratios (0.5-3.5). Exptl. results were presented in terms of total organic carbon (TOC) removal %, and nitrogenous products yield %. Based on GC-MS anal., a free radical reaction mechanism for SCWO of DBU was proposed. Results showed that temperature was the predominant factor to influence the rate of DBU oxidation, while oxidant ratio (nSR) significantly affected the N speciation in the exit stream. IPA addition had a significant impact on shifting recalcitrant aqueous ammonia NH⁺₄ in the liquid stream to gaseous nitrogen. It also increased TOC removal% (DBU + IPA) due to the increased free radicals produced by IPA oxidation

Journal of Supercritical Fluids published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, Category: oxazolidine.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Lehmann, Johannes published the artcileThe Kondrat’eva Reaction in Flow: Direct Access to Annulated Pyridines, Recommanded Product: 5-(4-Bromophenyl)oxazole, the publication is Organic Letters (2013), 15(14), 3550-3553, database is CAplus and MEDLINE.

A continuous flow inverse-electron-demand Kondrat’eva reaction has been developed that provides direct access to cycloalka[c]pyridines from unactivated oxazoles and cycloalkenes. The cycloadditions of both unactivated alkenes and deactivated oxazoles are promoted in continuous flow at elevated temperatures and pressures (230 °C, 750psi). E.g., reaction of 5-phenyloxazole and cyclopentene in presence of TFA gave 55% 4-phenyl-6,7-dihydro-5H-cyclopenta[c]pyridine (I). Annulated pyridines obtained by this one-step process are valuable scaffolds for medicinal chem.

Organic Letters published new progress about 72571-06-3. 72571-06-3 belongs to oxazolidine, auxiliary class Oxazole,Bromide,Benzene, name is 5-(4-Bromophenyl)oxazole, and the molecular formula is C9H6BrNO, Recommanded Product: 5-(4-Bromophenyl)oxazole.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Ribeiro, J. S. published the artcilePrediction of sensory properties of Brazilian Arabica roasted coffees by headspace solid phase microextraction-gas chromatography and partial least squares, SDS of cas: 20662-83-3, the publication is Analytica Chimica Acta (2009), 634(2), 172-179, database is CAplus and MEDLINE.

Volatile compounds in fifty-eight Arabica roasted coffee samples from Brazil were analyzed by SPME-GC-FID and SPME-GC-MS, and the results were compared with those from sensory evaluation. The main purpose was to investigate the relationships between the volatile compounds from roasted coffees and certain sensory attributes, including body, flavor, cleanliness and overall quality. Calibration models for each sensory attribute based on chromatog. profiles were developed by using partial least squares (PLS) regression. Discrimination of samples with different overall qualities was done by using partial least squares-discriminant anal. (PLS-DA). The alignment of chromatograms was performed by the correlation optimized warping (COW) algorithm. Selection of peaks for each regression model was performed by applying the ordered predictors selection (OPS) algorithm in order to take into account only significant compounds The results provided by the calibration models are promising and demonstrate the feasibility of using this methodol. in online or routine applications to predict the sensory quality of unknown Brazilian Arabica coffee samples. According to the PLS-DA on chromatog. profiles of different quality samples, compounds 3-methypropanal, 2-methylfuran, furfural, furfuryl formate, 5-methyl-2-furancarboxyaldehyde, 4-ethylguaiacol, 3-methylthiophene, 2-furanmethanol acetate, 2-ethyl-3,6-dimethylpyrazine, 1-(2-furanyl)-2-butanone and three others not identified compounds can be considered as possible markers for the coffee beverage overall quality.

Analytica Chimica Acta published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, SDS of cas: 20662-83-3.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Piloty, Markus published the artcileInvestigations on the reaction of amino acids with α-dicarbonyl compounds. II. Volatile products of the reaction of amino acids with diacetyl (2,3-butanedione), COA of Formula: C5H7NO, the publication is Zeitschrift fuer Lebensmittel-Untersuchung und -Forschung (1979), 168(5), 374-80, database is CAplus.

Glycine [56-40-6], α-alanine [56-41-7], β-alanine [107-95-9], phenylalanine [63-91-2], glycylalanine [3695-73-6], and NH₃ were reacted with diacetyl [431-03-8], in an aqueous medium. In addition to several N-free compounds, some nitrogenous heterocyclic products belonging to the classes oxazoles, pyrazines, pyrroles, and pyridines were identified. The pyridine derivatives have not previously been described in the literature. Spectral data are given and possible mechanisms of formation discussed in relation to food aroma.

Zeitschrift fuer Lebensmittel-Untersuchung und -Forschung published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, COA of Formula: C5H7NO.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem