Organic Communications Articles

Ethyl coumarin-3-carboxylate occupies an important position in the organic synthesis and is used in production of biologically active compounds. Thus, the data published over the last few years on the methods of synthesis and chemical properties of ethyl coumarin-3-carboxylate are reviewed here for the first time. The reactions were classified as coumarin ring reactions and ester group reactions, and some of these reactions have been applied successfully to the synthesis of biologically and industrially important compounds.

A simple and efficient asymmetric synthesis of (S,S)-Ethambutol has been carried out using a chiral butanediol. The synthesis was completed within six steps with an overall yield 53% and the enantiomeric purity of final product was 98%. All the reactions were very clean and the yields are excellent.

The reaction sequence leading to the formation of novel benzodioxaphosphole-2-oxide derivatives with aryl substituted azetidinone/thiazolidinone system were accomplished through facile condensation of aryloxy-1, 3, 2-benzodioxa phosphole-4-carbohydrazide-2-oxides (4a-e) with aromatic aldehydes to afford the corresponding the important intermediate N’-(4-substituted benzylidene)-2-(4-substituted phenoxy) benzo(1,3,2)dioxa phosphole-2-oxide-4-carbohydrazide(5a-h). This intermediate (5) on one direction by subsequent reation with chloro acetyl chloride and triethyl amine in dry 1,4-dioxane gives the title compounds with azetidinone system (6 a-h) and on the other direction on refluxing with mercapto acetic acid in dry 1,4-dioxane and anhydrous zinc chloride gives the title compounds with thiazolidinone system (7 a-h). The structure of these newly synthesized compounds were established by their elemental analysis and spectral data (IR, H 1, C 13and P 31-NMR).These compounds have been screened for their antimicrobial activity and all are showing significant anti bacterial and antifungal activity.

A series of 2-[2-oxo-2-(2-oxo-2H-chromen-3-yl)-ethylsulfanyl]-4-aryl-4,6,7,8-tetrahydro-3H-quinazolin-5-ones (7a-f) and 2-[2-oxo-2-(3-oxo-3H-chromen-2-yl)-ethylsulfanyl]-4-aryl-4,6,7,8-tetrahydro-3H-quinazolin-5-ones (9a-f) were synthesized and screened for their in vitro antibacterial activity against Staphylococcus aureus, Bacillus thuringiensis (Gram positive) , Escherichia coli and Klebsiella pneumonia (Gram negative) bacterial strains . Among all the compounds, 7b and 7d were shown highest activity against all the tested bacterial strains compared to the standard drug Gentamicin. These two quinazolinone derivatives (7b and 7d) could be considered as useful templates for further development of potential antibacterial agents.