Convenient One-Pot Synthesis of 2-Oxazolines from Carboxylic Acids (original) (raw)

Synthesis and Chemical Reaction of 2-Oxazoline 5-Ones Derivatives

International Journal of Chemical and Biomolecular Science, 2019

Owing the wide use of oxazoline compounds as starting materials for the preparation of heterocycles and their uses are still explored and some of wide application for industrial and biological fields, 2-oxazoline nucleus has formed a large number of potentially biologically active molecules on modifications. The synthesis, structures and biological activities of oxazoline derivatives have long been focused of research interest of organic chemists in the field of medicine, due to the potential biological activities exhibited by them. Looking into the medicinal importance of oxazoline moiety, it will be worthwhile to synthesize certain newer derivatives of oxazolines and evaluate them for their biological activities, in this research work we synthesize some new derivatives of oxazoline. Compound 4-benzyliden-2-(4-nitro-phenyl) 4H-oxazol-5-one (2a) was used as starting material which was prepared via the reaction of glycine with p-nitro benzoyl chloride in presence of NaOH followed by the reaction with benzaldehyde in the presence of acetic anhydride and fused sodium acetate the reaction was confirmed by further preparation via the reaction of compound (1) with N, N dimethyl benzaldehyde which yield compound 4-(4-N,N-dimethyl benzyliden) 2-(4-nitro-phenyl)-oxazol-5-one (2b) (scheme 1). Treatment of 4-benzyliden-2-(4-nitrophenyl)4H-oxazol-5-one (2a) with p-amino phenol afforded 4-benzyliden-1-(4-hydroxy-phenyl-2-(4-nitro phenyl) imidazol-5 one (3).

One-Step Synthesis of Oxazoline and Dihydrooxazine Libraries

Journal of Combinatorial Chemistry, 2007

Oxazolines appear in numerous medicinally active compounds and natural products of biological significance. 1 Additionally, they are valuable as synthetic intermediates or protecting groups 2 in organic synthesis, 3 and commonly appear in ligands for asymmetric synthesis ). 4 The most common mode of oxazoline synthesis involves preparation of a β-hydroxy amide followed by cyclization. Typical cyclization reagents include Burgess reagent, 5 PPh 3 /DIAD, 6 DIC/Cu(OTf) 2 ,7 molybdenum oxide, 8 and DAST/Deoxo-Fluor. 9 The six-membered homologous dihydrooxazines have been prepared by various methods that include [4+2] cycloadditions between N-acyl imines and alkenes, 10 1,4-dipolar cycloaddition reactions between olefins and aminomethyl ions, 11 and from stereochemically defined Nthioacyl-1,3-amino alcohols in the presence of Bu 4 NF and EtI. 12

An Efficient and High-Yield One-Pot Synthesis of Bis(oxazoline)s

Journal of the Chinese Chemical Society, 2006

An efficient and mild one-pot synthesis of bis(oxazoline) (BOX) ligands is developed from reactions of dicarboxy dichlorides with b-amino alcohols in the presence of 11.0 equiv. NEt 3 followed by the addition of 3.6 equiv. methanesulfonyl chloride (MsCl). Nine different BOX ligands were prepared in excellent yields of $ 80%. Advantages of this improved synthesis are mild reaction conditions, short total reaction time of 9 h, and high isolated yields.

A new chiral oxazoline derived from camphor and its conversion to (R)-2-methylalkanoic acids

Tetrahedron: Asymmetry, 2000

(1S,5R,7R)-(^)-10,10-Dimethyl-3-ethyl-4-oxa-2-azatricyclo[5.2.1.0 1,5 ]dec-2-ene 2 was prepared in 95% yield from (1S)-1-amino-2-exo-hydroxyapocamphane 1. The chiral oxazoline could be alkylated (LDA/ THF/^78 C/RX, RX=ethyl, n-propyl, n-butyl iodides or benzyl bromide) to 3 in 95% yield and >95% diastereoselectivity, and the products hydrolysed to (R)-2-methylalkanoic acids 4 (43±47% yield, 93±98% e.e.).