Study on the Condensation of Different Hydroxy Aromatic Aldehydes with 2-Substituted 2-Oxazolin-5-ones Generated in situ
American Journal of Heterocyclic Chemistry
Volume 5, Issue 1, March 2019, Pages: 1-3
Received: Jan. 25, 2019;
Accepted: Mar. 14, 2019;
Published: Apr. 8, 2019
Views 309 Downloads 88
Pubanita Bhuyan, Department of Chemistry, North Eastern Regional Institute of Science and Technology, Nirjuli, Itanagar, India
Pradeep K. Tripathy, Department of Chemistry, North Eastern Regional Institute of Science and Technology, Nirjuli, Itanagar, India
Follow on us
In view to synthesize some bioactive 2-Substituted 4-(hydroxybenzylidene)-2-oxazolin-5-ones through a disciplined route, a study on the condensation of 2-, 3- and 4- hydroxy aromatic aldehydes (6) with 2-Substituted 2-oxazolin-5-ones (5) was carried out. 2-Substituted 2-oxazolin-5-ones (5) which are also known as saturated azlactones and unstable, were generated in situ from α-N-Acylglycines (1) using various cyclising agents namely ethyl chloroformate (2), benzene sulphonyl chloride (3) and p-toluene sulphonyl chloride (4) in dry benzene in presence of triethylamine base. The hydroxyl group at 3- and 4- positions of aromatic aldehydes namely 4-hydroxy-3-methoxybenzaldehyde (6a), m-hydroxybenzaldehyde (6b)and p-hydroxybenzaldehyde (6c) produce 2-substituted 4-(p-hydroxy-m-methoxybenzylidene)-2-oxazolin-5-one (8a), 2-substituted-4 (m-hydroxybenzylidene)-2-oxazolin-5-one (8b) and2-substituted-4 (p-hydroxybenzylidene)-2-oxazolin-5-one (8c) respectively as their (Z)-isomers, whereas 2-hydroxy aromatic aldehyde namely salicylaldehydeproduces 3-N-acylaminocoumarins (9) on condensation with 2-Substituted 2-oxazolin-5-ones (5) in appreciable yields and good purity. The reaction seems to be initiated by the formation of an adduct (E)-2-substituted 4-(o-hydroxybenzylidene-2-oxazolin-5-ones (7), followed by intramolecular 1,5- bond cleavage of the 2-oxazolin-5-one ring by the vicinal phenolic group and subsequent recyclization led to the formation of resultant 3-N-acylaminocoumarins (9). It is noteworthy that free hydroxyl group bearing benzylidene moiety at 4-position of 2-oxazolin-5-ones (8) were obtained. All the steps can be carried out in one flask.
4-(Hydroxybenzylidene) Azlactones, 3-N-Acylaminocoumarins, Cyclisingagents, Synthons, in situ
To cite this article
Pradeep K. Tripathy,
Study on the Condensation of Different Hydroxy Aromatic Aldehydes with 2-Substituted 2-Oxazolin-5-ones Generated in situ, American Journal of Heterocyclic Chemistry.
Vol. 5, No. 1,
2019, pp. 1-3.
Copyright © 2019 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/
) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Sharma N, Banerjee J, Shrestha N and Choudhury D, A review on oxazolone, European J. Biomedical and Pharmaceutical Sciences 2015; 2: 964-87.
Jat RL, Mishra R and Pathak D, International J. Pharmacy and Pharmaceutical Sciences 2012; 4: 378-80.
Erlenmeyer E and Stadlin W, Liebigs. Ann. chem. 1904; 337: 283-85.
Baltazzi E and Devis EA, Chem. Ind. (London) 1962; 929.
Takagaki H, Tanabe S, Asoka M and Takel H, Chem. Lett.1979; 347-50.
Tripathy PK, Indian J. Heterocyclic Chem.1992; 2: 77-80.
Review: Rao YS and Filler R, Synthesis 1975; 749-64.
Erlenmeyer E and Matter O, Liebigs. Ann. Chem. 1904; 337:271-3.
Tripathy PK and Mukerjee AK, Indian J. Chem. 1987; 26B: 61-62.
Ashare Ram and Mukerjee AK, Indian J. Chem. 1986; 25B: 423-24.
Tripathy PK and Mukerjee AK, Heterocycles 1987; 26:1517-20.
Mogilaiah K, Prashanthi M and Reddy CH, Indian J. Chem. 2003; 42B: 2126-28.
Marrian DH, Russel PB and Todd AR, Biochem. J. 1949; 45: 533.
Kirby GW, Michael J and Narayanaswami S, J. Chem. Soc. Perkin Trans- 1 1972; 203.
Mukerjee AK and Ashare Ram, Chemical Reviews 1991; 91: 1-24.