Ethyl acetate as solvent

Methyiaminoacetonitrile (216) reacts with carbon disulfide in the presence of acetic anhydride with ethyl acetate as solvent to give 2-thio-3-methyl-A-4-thiazoline in 74% yield (Scheme 113a) (326). If the reaction is carried out using benzaldehyde in place of acetic anhydride, the corresponding 5-benzylideneamino derivative of 217 is obtained in 70% yield. 

Fig. 1. Time courses of the chemiluminescence intensity from oxalate—hydrogen peroxide systems in ethyl acetate as solvent, 0.7 mM TCPO. The curves correspond to the following concentrations of triethylamine (TEA) catalyst A, 0.05 mM B, 0.10 mM and C, 0.20 mM (70).

A similar synthesis starting with l-(2-nitrobenzyl)pyrrol-2-aldehyde used ethanol-ethyl acetate as solvent (62). Indoles are prepared in excellent yield by hydrogenation of o-nitrobenzyl ketones over Pd-on-C (i). Azaindoles are correspondingly prepared from nitropyridines (97). 

The chemoenzymatic synthesis of the analgesic U-(—)-50,488 [41] and new C2-symmetric bisaminoamide ligands derived from N,N-disubstituted trans-cyclohexane, ,2-diamine [41] has been possible by a CALB-catalyzed resolution using ethyl acetate as solvent and acyl donor [42]. 

For example, the lycopene available on the market is supplied mainly by LycoRed (www.lycored.com), a company that uses a classical extraction system (ethyl acetate as solvent) and maintains a monopoly position for lycopene production on a large scale. The manufacturing of the Lyc-O-Mato oleoresin (recognized by European Regulation 258/97/EC) product of LycoRed is almost identical to the production of the food additive and includes physical operations to separate the pulp from ripe tomatoes extracted according to GMPs and lSO-9002-certified procedures. The final product contains 6 to 15% lycopene the total lycopene recovery from pulp reaches 85% and from paste around 50%. 

Treatment of 1 with chromium trioxide or chromic acid in a mixture of acetone, acetic acid, and acetic anhydride at — 60°C produces a mixture of 2 and iV -demethylvinblastine (55) (71). When this crude mixture is treated with formic acid in acetic anhydride, 2 is obtained in 50-70% yield based on starting vinblastine. A modification of this procedure involves the use of preformed chromic acid with either tetrahydrofuran or ethyl acetate as solvent. Using these methods, yields of 2 as high as 90% have been obtained (72). 

Are you surprised to find such big differences in the Kievi values of 1-naphtol for the various solvents If not, try to explain these differences. You choose ethyl acetate as solvent for the extraction. Why not n-octanol ... 

Acylcobalt carbonyls formed from acyl halides appear to isomerize less readily. No isomerization was found using isobutyryl bromide or n-butyryl chloride in nonpolar solvents such as hexane or benzene. Some isomerization was found with diethyl ether and ethyl acetate as solvents, again promoted by absence of carbon monoxide. Curiously, no isomerization... 

In this context it is interesting to note the recent reports of fluorous catalysis without fluorous solvents [68]. The thermomorphic fluorous phosphines, P[(CH2)m(CF2)7CF3]3 (m=2 or 3) exhibit ca. 600-fold increase in n-octane solubility between -20 and 80 °C. They catalyze the addition of alcohols to methyl propiolate in a monophasic system at 65 °C and can be recovered by precipitation on cooling (Fig. 7.20) [68]. Similarly, perfluoroheptadecan-9-one catalyzed the epoxidation of olefins with hydrogen peroxide in e.g. ethyl acetate as solvent [69]. The catalyst could be recovered by cooling the reaction mixture, which resulted in its precipitation. 

Reference Solutions. Prepare reference solutions containing 1 mg/ml of each of the substances Hsted in Table 18, using ethyl acetate as solvent. 

However, in 1944 it was reported by Sakurai and Tanabe that with acetone or ethyl acetate as solvent, Pd-BaSOa as catalyst (no regulator) and in the presence of A, A -dimethylaniline as an HCl acceptor, the Rosenmund reduction occurs cleanly and rapidly at room temperature. More recently, three other groups have reported mild and effective variants of the Rosenmund. In each case the key element appears to be the use of a basic additive to remove the HCl produced by the reduction and possibly also to regulate the catalyst activity. All the methods involve the use of closed hydrogenation apparatus and thus have a clear safety advantage over the classical procedure. 

Separation of mixtures of plasticisers can be achieved by thin layer chromatography on a Kieselgel plate using mixtures of benzene and ethyl acetate as solvents. The separated bands obtained can be examined by infrared techniques. 

Another method, which is faster and offers a high separation of Tc-MIBI from impurities was introduced by Patel et al. (1995). Whatman 3MM paper strips are used and ethyl acetate as solvent. Tc-sestamibi moves with an Rf of 0.55-0.75, while Tc-pertechnetate and reduced, hydrolized Tc-activity remain at the start. 

The mixtures were piuified by flash-chromatography using hexane and ethyl acetate as solvents. A 35 65 volumetric ratio of ethyl acetate to hexane was selected (Rf values Table 7). The piuified compounds were analyzed by NMR. With the aid of proton-proton NMR (COSY-NMR) spectra and proton-detected multiple bond coherence NMR (HMBC-NMR) spectra, the structures of the coupled compounds [27a-h] were determined. The HMBC-NMR assignments of compound [27c] (lactosyl derivative) are shown as an example in Figure 4. 

The PVAc homopolymer (1) and the VAc/Unseed oil (10%) copolymer (2) obtained in organic solvent were tested using the EN205-D3 test. In agreement with this test the adhesive strength can be measured in dry conditions (D3-1) or in wet conditions (D3-3). The presence of ethyl acetate as solvent (solid content 50%)... 

In general 3-benzylidenechroman-4-ones are prepared by condensation of chroman-4-ones with aromatic aldehydes (72). Strong alkaline (55) or acidic (75) conditions can be applied only if eventual sensitive substituents are suitably protected. Using dry hydrogen chloride in acetic acid Boehler and Tamm synthesized 5,7-di-O-methyleucomin (33) from 5,7-dimethoxychroman-4-one and anisaldehyde (9). Later Krishna-MURTY et al. (45) observed the simultaneous formation of a C-6 or C-8 a-chlorobenzylated product (34) in this reaction. Starting from O-benzoylated compounds 5,7-di-O-benzoyleucomin (35) and 4, 5,7-tri-0-benzoyl-4 -demethyleucomin (36) are easily prepared by this method using diethyl ether and ethyl acetate as solvents respectively (45). The unprotected phenolic compounds can be condensed successfully in boiling acetic anhydride (23, 24). The relatively low yield of 5,7-di-O-... 

However, if a choice were to be made between benzene and ethyl acetate as solvents for separating ethanol and water, clearly benzene is the more selective of the two. Other considerations, however, might show neither to be very desirable. 

Fig. 3. Monomer-copolymer composition in the copolymeri zation of vinyl fluoride at 30°C with 02/B(i-C4H9)3 = 0.5 initiator (based on total monomer charged) and ethyl acetate as solvent. Comonomers vinyl chloride (VCl), acrylonitrile (AN), vinyl acetate (VA), chlorotri-fluoroethylene, ethylene, tetrafluoroethylene, cis-l-hydropentafluoropropene (C3F5H), hex-afluoropropene (CsFe), hexafluorocyclobutene (c-C4Fe), and vinylidene fluoride (VF2). From Ref. 86.

The diterpenes are discussed in connection with the mono- and sesquiterpene derivatives with which they are closely related according to modern ideas of biosynthesis. Brieskorn s team [24, 24 a] has studied the bitter tasting picrosalvin in Salvia species. It is a diterpene-o-diphenol lactone [24 a] which occurs also in other Labiatae. Nicholas [180] has worked likewise on Salvia sclarea and utilised successfully two-dimensional TLC on sihea gel G layers. He used ethyl acetate as solvent and was able to justify the hypothesis about the incorporation of into sclareol. 

Silica gel with toluene-ethyl acetate as solvent phase (4 1) and detection by... 

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