51127-16-3

Basic information

• Product Name: rac-4-ethyl-2-phenyloxazol-5(4H)-one
• CAS NO: 51127-16-3
• Molecular Weight: 189.214
• Mol File: 51127-16-3.mol

Chemical Properties

• CAS DataBase Reference: rac-4-ethyl-2-phenyloxazol-5(4H)-one(CAS DataBase Reference)
• NIST Chemistry Reference: rac-4-ethyl-2-phenyloxazol-5(4H)-one(51127-16-3)
• EPA Substance Registry System: rac-4-ethyl-2-phenyloxazol-5(4H)-one(51127-16-3)

Safety Data

• Hazardous Substances Data: 51127-16-3(Hazardous Substances Data)

Upstream product

• 79893-94-0 N-benzoyl-α-aminobuttersauremethylester 
• 98-88-4 benzoyl chloride 
• 108-24-7 acetic anhydride 
• 5468-52-0 N-benzoyl-2-aminobutyric acid 

Downstream Products

• 5468-52-0 N-benzoyl-2-aminobutyric acid 
• 28358-79-4 N-propionyl-benzamide 
• 5500-46-9 N-benzamide 
• 5202-76-6 N-benzamide 
• 34047-84-2 (S)-N-benzoyl-3-methylalanine methyl ester 
• 886466-69-9 5-benzyloxycarbonyloxy-4-ethyl-2-phenyloxazole 
• 1562411-30-6 C₈₄H₃₃N₃O₂ 

Relevant articles and documents

Asymmetric Aza-Diels-Alder Reactions of in Situ Generated β,β-Disubstituted α,β-Unsaturated N-H Ketimines Catalyzed by Chiral Phosphoric Acids

A novel asymmetric synthesis of dihydropyridinones with vicinal quaternary stereocenters has been realized by asymmetric aza-Diels-Alder reactions of 3-amido allylic alcohols with oxazolones enabled by chiral phosphoric acid catalysis. A series of aryl/alkyl- and alkyl/alkyl-disubstituted 3-amido allylic tertiary alcohols and 4-substituted oxazolones could be well tolerated in these reactions, producing dihydropyridinones with excellent diastereoselectivities and high enantioselectivities. Mechanistic study and control experiments were performed to shed light on the reaction mechanism, in which a configurationally defined β,β-disubstituted α,β-unsaturated N-H ketimine was proposed as the key intermediate.

Group-Assisted Purification Chemistry for Asymmetric Mannich-type Reaction of Chiral N-Phosphonyl Imines with Azlactones Leading to Syntheses of α-Quaternary α,β-Diamino Acid Derivatives ?

An asymmetric Mannich-type reaction between chiral N-phosphonyl imines and azlactones [oxazol-5(4H)-ones] has been established under convenient conditions at room temperature. The reaction was performed without using any bases, additives, or catalysts to achieve up to excellent chemical yields and diastereoselectivity for 32 examples. The α-quaternary syn-α,β-diamino acid products were purified simply by washing the crude mixtures with cosolvents, following the group-assisted purification chemistry/technology, without involving traditional chromatography or recrystallization methods. The auxiliary can be readily removed and recycled for reuse. The absolute configuration was unambiguously assigned by X-ray structural analysis.

Bifunctional squaramide-catalyzed synthesis of chiral dihydrocoumarins via ortho-quinone methides generated from 2-(1-tosylalkyl)phenols

A bifunctional squaramide-catalyzed reaction of azlactones with o-quinone methides in situ generated from 2-(1-tosylalkyl)-phenols has been successfully developed under basic conditions, providing an efficient and mild access to chiral dihydrocoumarins bearing adjacent tertiary and quaternary stereogenic centers in high yields with excellent diastereo- and enantioselectivities.

Regiodivergent Enantioselective γ-Additions of Oxazolones to 2,3-Butadienoates Catalyzed by Phosphines: Synthesis of α,α-Disubstituted α-Amino Acids and N,O-Acetal Derivatives

Phosphine-catalyzed regiodivergent enantioselective C-2- and C-4-selective γ-additions of oxazolones to 2,3-butadienoates have been developed. The C-4-selective γ-addition of oxazolones occurred in a highly enantioselective manner when 2-aryl-4-alkyloxazol-5-(4H)-ones were employed as pronucleophiles. With the employment of 2-alkyl-4-aryloxazol-5-(4H)-ones as the donor, C-2-selective γ-addition of oxazolones took place in a highly enantioselective manner. The C-4-selective adducts provided rapid access to optically enriched α,α-disubstituted α-amino acid derivatives, and the C-2-selective products led to facile synthesis of chiral N,O-acetals and γ-lactols. Theoretical studies via DFT calculations suggested that the origin of the observed regioselectivity was due to the distortion energy that resulted from the interaction between the nucleophilic oxazolide and the electrophilic phosphonium intermediate.

Bispalladacycle-catalyzed Michael addition of in situ formed azlactones to enones

The development and further evolution of the first catalytic asymmetric conjugate additions of azlactones as activated amino acid derivatives to enones is described. Whereas the first-generation approach started from isolated azlactones, in the second-generation approach the azlactones could be generated in situ starting from racemic N-benzoylated amino acids. The third evolution stage could make use of racemic unprotected α-amino acids to directly form highly enantioenriched and diastereomerically pure masked quaternary amino acid products bearing an additional tertiary stereocenter. The step-economic transformations were accomplished by cooperative activation by using a robust planar chiral bis-Pd catalyst, a Br?nsted acid (HOAc or BzOH; Ac=acetyl, Bz=benzoyl), and a Br?nsted base (NaOAc). In particular the second- and third-generation approaches provide a rapid and divergent access to biologically interesting unnatural quaternary amino acid derivatives from inexpensive bulk chemicals. In that way highly enantioenriched acyclic α-amino acids, α-alkyl proline, and α-alkyl pyroglutamic acid derivatives could be prepared in diastereomerically pure form. In addition, a unique way is presented to prepare diastereomerically pure bicyclic dipeptides in just two steps from unprotected tertiary α-amino acids. Flourishing step economy: The evolution of the catalytic asymmetric addition of azlactones to enones is described. The first-generation approach started from isolated azlactones. In the second-generation approach azlactones could be generated in situ from racemic N-benzoylated amino acids. The third evolution stage could directly use racemic unprotected α-amino acids to form a large number of highly enantioenriched quaternary amino acids derivatives (see figure). Copyright

Self-association free bifunctional thiourea organocatalysts: Synthesis of chiral α-amino acids via dynamic kinetic resolution of racemic azlactones

Concentration-independent high enantioselectivity in the dynamic kinetic resolution (DKR) of racemic azlactones affording chiral α-aminoesters has been achieved using self-association free thiourea-based dimeric cinchona alkaloid organocatalysts. Detailed

Enantioselective quaternization of 4-substituted oxazol-5-(4H)-ones using recoverable Cinchona-derived dimeric ammonium salts as phase-transfer organocatalysts

Dimeric anthracenyldimethyl-derived Cinchona ammonium salts are used as chiral organocatalysts (5 mol %) for the enantioselective 4-alkylation of 4-substituted azlactones. The corresponding adducts bearing a new quaternary center were obtained with up to

Polyclonal antibodies: A cheap and efficient tool for screening of enantioselective catalysts

Enantioselective polyclonal antibodies have been produced and characterized to develop a high-throughput screening method for lipase activity fingerprinting, with a view to the enantioselective hydrolysis of azlactones.

Synthesis and anti-HIV-1 activity of a series of imidazo[1,5- b]pyridazines

A series of substituted imidazo[1,5-b]pyridazines have been prepared and tested for inhibitory activity against the reverse transcriptase of HIV-1 (RT) and their ability to inhibit the growth of infected MT-4 cells. Crystal data are reported on two compounds, 15c and 33. From the structure-activity relationships developed within this and other series, it is proposed that key features of the interaction with RT include hydrogen-bond acceptor and aromatic π-orbital bonding with the imidazopyridazine nucleus and a benzoyl function separated from the heterocycle by a suitable spacer group. Exceptional activity against the reverse transcriptase of HIV-1 (IC50 = 0.65 nM) was obtained with a 2-imidazolyl-substituted derivative, 7-[2-(1H- imidazol-1-yl)-5-methylimidazo[1,5-b]pyridazin-7-yl]-1-phenyl-1-heptanone (33) which is attributed to additional binding of the imidazole sp2 nitrogen atom. A number of the compounds in this series also inhibit the replication of HIV-1 in vitro in MT-4 and C8166 cells at levels observed with the nucleoside AZT.

AN EFFICIENT TRANSFORMATION OF N-ACYL-α-AMINO ACIDS INTO DIACYLAMINES VIA 2,4-DISUBSTITUTED OXAZOL-5(4H)-ONES

Base-catalyzed oxygenative decarboxylation of a variety of 2,4-disubstituted oxazol-5(4H)-ones in benzene with triethylamine or in dimethylsulfoxide with potassium tert-butoxide gives diacylamines.KEYWORDS - base-catalyzed autooxidation; selective oxygenation; decarboxylation; oxazol-5(4H)-one; N-acyl-α-amino acid; diacylamine