Isopropyl butyrate

The substrate (9 mmol), isopropyl butyrate (18 mmol) and toluene (9 mL) were then added and the Schlenk tube was inserted in an oil bath at 73 °C, which indicated the started of the reaction. The reaction mixture was stirred at 70 °C for 23 h at a pressure of 200 mbar. Small aliquots of reaction mixture were taken for gas chromatography analysis. For preparative purposes, the reaction mixture was concentrated, filtered, washed with toluene and concentrated in vacuo to yield the crude product. 

Hulshof et al. introduced 10 as an alcohol racemization catalyst [31]. Alcohol DKR was performed with 0.1mol% of 10, CALB, isopropyl butyrate as the acyl donor, potassium carbonate and about 20mol% of the corresponding ketone at 70°C (Scheme 1.23). Without the ketone, yield and optical purity of the product ester were decreased significantly. 2-Propanol produced by the acyl transfer reaction was removed at reduced pressure during the DKR to shift the equilibrium to acylated products. 

All the spectroscopic approaches applied for structural characterization of mixtures derive from methods originally developed for screening libraries for their biological activities. They include diffusion-ordered spectroscopy [15-18], relaxation-edited spectroscopy [19], isotope-filtered affinity NMR [20] and SAR-by-NMR [21]. These applications will be discussed in the last part of this chapter. As usually most of the components show very similar molecular weight, their spectroscopic parameters, such as relaxation rates or selfdiffusion coefficients, are not very different and application of these methodologies for chemical characterization is not straightforward. An exception is diffusion-edited spectroscopy, which can be a feasible way to analyze the structure of compounds within a mixture without the need of prior separation. This was the case for the analysis of a mixture of five esters (propyl acetate, butyl acetate, ethyl butyrate, isopropyl butyrate and butyl levulinate) [18]. By the combined use of diffusion-edited NMR and 2-D NMR methods such as Total Correlation Spectroscopy (TOCSY), it was possible to elucidate the structure of the components of this mixture. This strategy was called diffusion encoded spectroscopy DECODES. Another example of combination between diffusion-edited spectroscopy and traditional 2-D NMR experiment is the DOSY-NOESY experiment [22]. The use of these experiments have proven to be useful in the identification of compounds from small split and mix synthetic pools. 

Hexyl butyrate Isoamyl acetate Isopropyl butyrate Methyl acetate Methyl butyrate Methyl capronate Methyl isobutyrate Methyl-a-methylbutyrate Propyl acetate cA-Terpineol hydrate ... 

Figure 24 (a) ID 400 MHz H NMR spectrum of the nine-component mixture in CDC13. (1) DL-isocitric lactone, (2) (S)-(+)-0-acetylmandelic acid, (3) DL-iV-acetylho-mocysteine thiolactone, (4) ( + )-sec-butyl acetate, (5) propyl acetate (6) isopropyl butyrate, (7) ethyl butyryl acetate, (8) butyl levulinate, (9) hydroquinine-9-phenanthryl ether, (b) PFG ID H NMR spectrum of the mixture without hydroquinine-9-phe-nanthryl ether, (c) PFG ID H NMR spectrum of the nine component mixture using LED sequence. Chemical shifts arising from compounds 1 and 2 are shown. All other shifts are from compound 9. The PFG conditions were the same as in (b). 

Ans. (a) Isopropyl butanoate (lUPAC) isopropyl butyrate (common), (b) phenyl propanoate (lUPAC) phenyl propionate (common). 

Isopropyl butanoate. See Isopropyl butyrate Isopropyl butyrate... 

Isoeugenyl phenylacetate Isojasmone a-Isomethylionone Isopropyl acetate p-Isopropylacetophenone Isopropyl benzoate Isopropyl butyrate Isopropyl cinnamate Isopropyl formate Isopropyl hexanoate... 

Isoeuqenyl phenylacetate Isojasmone Isomenthone a-lsomethylionone Isomethyl-p-ionone Isononanal Isononyl acetate Isononyl propionate Isophorone Isopropyl benzoate Isopropyl butyrate... 

Mesityl oxide Methyl benzoate Nitroethane Propyl alcohol Propylene dichloride Tetrahydrofurfuryl alcohol Trichloroethylene solvent, cellulose ethers Acetone oxime Acetophenone Butyl benzoate Butyl formate Cyclohexane Cyclohexyl acetate Dibutyl tartrate Diethyl oxalate Epichlorohydrin Ethyl butyrate Ethylene glycol diacetate Ethyl-(S)-lactate Ethyl propionate Isopropyl butyrate Mesityl oxide... 

Isopropyl propionate 211-319-1 Ethyl senecioate 211-320-7 Isopropyl butyrate 211-322-8... 

Butyraldehyde propylene glycol acetal Ethyl isovalerate Ethyl 2-methyl butyrate Ethyl pivalate Ethyl valerate Heptanoic acid Hexyl formate Isoamyl acetate Isobutyl propionate Isopropyl butyrate Isopropyl isobutyrate 4-M ethoxy-4-methyl pentanone-2... 

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