Comparative Synthesis and Cyclization of 1, 5-Diketone

Syeda Shaista Gillani,Ambreen Mushtaq

doi:10.36648/2472-1123.5.2.1

Abstract

Diketones are found to be extremely reactive due to owing electron deficient carbon atoms of double carbonyls groups and are extensively used for huge range of organic synthesis such as tetracyclones, triazines, inidazoles, quinoxalines, pyrazinones, peroxides, Photoluminescent compounds, cis-jasmone, furan, pyrroles and thiophenes etc. 1, 5-diketone (1, 3, 5-triphenyl-1, 5-pentanedione) has been synthesized by the condensation of acetophenone and benzaldehyde at different reaction conditions while stirring at 25°C. Further, the synthesized 1, 3, 5-triphenyl-1, 5-pentanedione has been condensed with benzil and also cyclized in acidic as well as in basic media to get the product. The progress of reaction was monitored by TLC (thin layer chromatography , Eluent; n-hexane/ethylacetate) visualizing under UV lamp and Iodine bath.

Highlights

ExperimentalDiketones play a very important role in the synthesis of organic chemistry
A number of strategies have been employed for the synthesis of diketones such as carbonmonoxide insertion into carbon-lithium bonds [1], light induced C=C bond cleavage of Enanimones [2], oxidatisve coupling of imidazo [1,2] pyridines and methyl ketones [3,4,5], soft enolization of ketones [7,8], α-halo ketones and TDAE [9], Methyl ketones and α-bromo ketones [10,11], unsymmetrical disubstituted acetylene by mercuric ion catalysis [12], enol esters and ketones in manganic acetate [13,14], alkyl copper reagents and conjugated enones [15,16], silylenolethers [17,18], dimerization of ketone enolates [19,20,21], nito-olefins [22], nitro alkanes [23], organometallic compounds [24], methyl ketone carbanions and α-ketoketenedithioacetals [25] and birch reduction [26]. 1, 5diketone owing to electrophilic centers of two carbonyl groups has significant importance as an intermediate in the synthesis of many heterocyclic [27,28] and polyfuntional [29,30]
Working on the methodology of Hirsh and Bailey [31] acetophenone and benzaldehyde were condensed in the presence of sodium hydroxide and ethanol to synthesize 1, 3, 5-triphenyl-1, 5-pentanedione 3

Summary

Introduction

ExperimentalDiketones play a very important role in the synthesis of organic chemistry. Purification was done by recrystallization (ethanol/n-hexane) to afford pure compound (5.98g , 73% yield) as a white crystal, m.p=82-85oC.1H NMR (500 MHz, CDCl3) 6.62-7.39 m 15H, 3.513 d 2H; 13C NMR (126 MHz, CDCl3) 49.4, 126.41, 127.48, 128.04, 128.34, 128.54, 129.35, 130.54, 130.66, 131.12, 140.63, 140.66, 143.03; IR (neat) 3028, 1684, 1287, 687 cm-1; UV-VIS; λmax (CH2Cl2 / nm)=230, 260 nm; LC-MS ES+ (m/z): [M+H]+329.25.

Results

Conclusion