26348-47-0Relevant articles and documents
Synthesis of oxazoles from enamides via phenyliodine diacetate-mediated intramolecular oxidative cyclization
Zheng, Yunhui,Li, Xuming,Ren, Chengfeng,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
, p. 10353 - 10361 (2013/01/15)
A group of functionalized oxazoles were synthesized in moderate to good yields from enamides via phenyliodine diacetate (PIDA)-mediated intramolecular cyclization. The main advantageous features of the present method include its broad substrate scope and the heavy-metal-free characteristic of the oxidative carbon-oxygen bond formation process.
Kinetics and mechanism of amine-catalysed solvolysis of azlactone in water-dioxan mixtures
Ismail, Amel M.
, p. 49 - 54 (2008/09/20)
The effect of replacing solvent water by dioxan up to 50% v/v on the rate of catalytic-amine solvolysis of azlactone has been measured spectrophotometrically in the temperature range 40-60°C. Addition of an organic solvent to water largely decreases the r
Kinetics and mechanism of the nucleophilic ring opening of oxazolinone in mixed aqueous solvents
Ismail, Amel M.
, p. 916 - 922 (2008/02/09)
Solvent effect on the kinetics of ring opening of oxazolinone has been investigated in neutral and alkaline medium in dioxan-water mixtures up to 50% v/v in the temperature range of 40-60°C. The thermodynamic activation parameters have been calculated and discussed in terms of solvation effect. The isokinetic temperature in both media (310, 303 and 298 K for neutral, alkaline hydrolysis by NaOH and Na2CO3 respectively) indicates that the reaction is entropy controlled and that solute-solvent interactions play an important role. The correlation of logk2 against either Grunwald-Wientien Y values or log[H2O] Is found to be linear, while the correlation between logk2 and the reciprocal of the dielectric constant is nonlinear. The estimated value of the slope m in Grunwald relationship gives a value less than unity indicating SAN/SN2 mechanism. Mechanism for the oxazolinone ring opening has been proposed.
Practical preparation of Z-α-(N-acetylamino)- and Z-α-(N-benzoylamino)-α,β-unsaturated acids
Jursic, Branko S.,Sagiraju, Sarada,Ancalade, Dustin K.,Clark, Traneil,Stevens, Edwin D.
, p. 1709 - 1714 (2008/02/01)
An efficient two-step synthetic procedure for the preparation of numerous variations of N-protected α,β-unsaturated α-amino acids and their corresponding esters from N-protected glycine and either aliphatic or aromatic aldehydes was developed. The reaction involved cyclization of the N-protected glycine into oxazolone, condensation with the aldehyde, and ring opening with a base. Copyright Taylor & Francis Group, LLC.
An usual behaviour of ethers in presence of azlactones under ultrasound irradiation to give esters
Rajaram, S.,Lalitha, N.,Iyengar, D. S.
, p. 761 - 763 (2007/10/03)
The phenomenon of ester formation from ethers and azlactones under sonolysis has been observed.
Synthesis of L-threo- and L-erythro-amino acids: novel probes for conformational analysis of peptide side chains
Oba, Makoto,Ueno, Ryuichi,Fukuoka, Mika,Kainosho, Masatsune,Nishiyama, Kozaburo
, p. 1603 - 1610 (2007/10/02)
An efficient and convenient route for the preparation of L-threo- and L-erythro-amino acids 5 as probes for the conformational analysis of peptide side chains by NMR spectroscopy is described.Stereoselective incorporation of deuterium into the α,β-positions of amino acid 5 was accomplished by catalytic deuteration of dehydroamino acid derivatives 1 and 2 followed by a combination of enzymic optical resilution and the racemization at the 2-position.Using these doubly labelled amino acids, it was possible to obtain vicinal coupling constants between carbonyl carbon and prochiral β-protons, J(13C-1Hβ1) and J(13C1-1Hβ2), through 13C NMR spectroscopy alone.We also demonstrate the determination of the fractional populations of rotamers in respect of the Cα-Cβ bond of the amino acids using the measured coupling constants.
A new methodology for the synthesis of N-acylaminocinnamates
Rao, Ch. Chennakesava,Lalitha, Nagubandi
, p. 3 (2007/10/02)
A new synthesis of biologically active N-protected amino acids (2) and amides (4) from 4-ylidene-5(4H)-oxazolones (1) is described.
Selective and Convenient Enzymatic Separation of Geometric Isomers of N-Protected-α-dehydrophenylalanine Esters
Shin, Chung-gi,Seki, Masashi
, p. 887 - 888 (2007/10/02)
Selective enzymatic hydrolysis of a mixture of (Z)- and (E)-N-protected-ΔPhe-OMe with α-chymotrypsin A took place to give (Z)-ΔPhe-OH and (E)-ΔPhe-OMe
Asymmetric Hydrogenation of Prochiral Alkenes Catalysed by Ruthenium Complexes of (R)-(+)-2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl
Kawano, Hiroyuki,Ikariya, Takao,Ishii, Youichi,Saburi, Masahiko,Yoshikawa, Sadao,et al.
, p. 1571 - 1575 (2007/10/02)
Two chiral ruthenium(II) complexes containing (R)-(+)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl were found to be effective catalysts for the asymmetric hydrogenation of 2-acylaminoacrylic and 2-acylaminocinnamic acids under mild conditions, to afford N-acyl-(R)-α-amino acids with 49 - 95 percent optical purity.The differences between the asymmetric hydrogenations effected by RuII- and RhI-(R)-BINAP systems are discussed.Asymmetric hydrogenation of methylenesuccinic acid and its derivatives with Ru-(R)-BINAP is also described.
N-Acylphenylalanines and Related Compounds. A New Class of Oral Hypoglycemic Agents
Shinkai, Hisashi,Toi, Koji,Kumashiro, Izumi,Seto, Yoshiko,Fukuma, Mariko,et al.
, p. 2092 - 2097 (2007/10/02)
N-Benzoyl-DL-phenylalanine (1) was found to possess hypoglycemic activity.A series of the analogues of compound 1 were prepared and evaluated for their blood glucose lowering activity.Both the steric effects of the phenylalanine moiety and the effects of variations in the acyl moiety were investigated.This study elucidated some of the structure-activity relationships and led to the development of N-(4-ethylbenzoyl)-D-phenylalanine (34), which was 50 times more potent than the initial compound 1.
