Ethylating compounds

Hydrolysis of Potassium Ethyl Sulphate. Dissolve about i g. of the crystals in about 4 ml. of cold distilled water, and divide the solution into two portions, a) To one portion, add barium chloride solution. If pure potassium ethyl sulphate were used, no precipitate should now form, as barium ethyl sulphate is soluble in water. Actually however, almost all samples of potassium ethyl sulphate contain traces of potassium hydrogen sulphate formed by slight hydrolysis of the ethyl compound during the evaporation of its solution, and barium chloride almost invariably gives a faint precipitate of barium sulphate. b) To the second portion, add 2-3 drops of concentrated hydrochloric acid, and boil the mixture gently for about one minute. Cool, add distilled water if necessary until the solution has its former volume, and then add barium chloride as before. A markedly heavier precipitate of barium sulphate separates. The hydrolysis of the potassium ethyl sulphate is hastened considerably by the presence of the free acid Caustic alkalis have a similar, but not quite so rapid an effect. 

Analogously, l-brcano-3-oxiininobutan-2-one yields the 4-oximino-ethyl compound (67), while chloromalonic dialdehyde gives rise to the S-formylthiazole (68) (Scheme 31) (618). 

Z Arrangement was also ascribed to the isomer absorbing at higher field in the case of the ethyl compounds. CH and CH2 protons near the ring nitrogen are shielded by the aromatic ring in the Z compound. The protons at the ring carbon absorb at lower field (near 5.2 p.p.m.) in the Z compounds than in the E compounds (4.50-4.70 p.p.m.). The chemical shift of this proton may be used for E-Z discrimination in further substances. 

The epimeric 17 -methylandrost-5-ene-3, 17a-diol could be isolated as a by-product from larger scale experiments. Reaction of (49) with ethyl-magnesium halide affords the corresponding 17a-ethyl compound. In this... 

Athyl-jodid, n, ethyl iodide, iodoethane. -rho-danid, n, ethyl thiocyanate, -rot, n. ethyl red. -schwefelsaure, /, ethylsulfurie acid, -senfol, n, ethyl mustard oil (CsHcNCS). -sulfhydrat, n, ethyl hydrosulfide, -verbindung, /, ethyl compound, -wasserstoff,... 

Kurogoshi and Hori [ 104] determined the crystal structures of the mesogenic ethyl and butyl 4-[4-(4-n-octyloxybenzoyloxy)benzylidene]aminobenzoates. The compounds have different phase sequences crystal-smectic A-nematic-isotropic and crystal-smectic C-smectic A-nematic-isotropic for the ethyl and butyl compounds, respectively. Both compounds have layer structures in the solid phase. The butyl compound contains two crystallographically independent molecules. Within the layers, adjacent molecules are arranged alternately so as to cancel their longitudinal dipole moments with each other. In the ethyl compound the core moieties are almost perpendicular to the layer plane, while in the butyl compound these moieties are tilted in the layer. 

Both alkyl and aryl metals have been studied, but not a very wide range of compounds. Several studies of triphenylarsene and triphenylstibine have been done. Methyl and ethyl compounds of arsenic, germanium, mercury, bismuth, and lead essentially complete the list. In virtually all cases the results have been clouded by difficulties in effecting chemical separation without altering the product distribution. The results do, nonetheless, lead to valid and important conclusions. 

Brain, F.H. and Gibson, G.S. (1939) The organic compounds of gold. Part VII. Methyl and ethyl compounds. Journal of the Chemical Society, 762. 

TiCRjtftc) was prepared starting from Ti(NR2)4 4,5) or TiCl4 (6). The structure of the ethyl compound was elucidated by X-ray studies (7, S). The titanium atom is eight-coordinated by the sulfur atoms of the four chelating ligands and the coordination geometry closely approximates to that of a dodecahedron. 

Two types of FeQl) dithiocarbamates are reported. To the first type belong the complexes Fe(R2powder diffraction pattern shows the ethyl compound to be isomorphous with the five-coordinated, dimeric Cu(II) complex (18), so it is to be expected that the fifth Fe-S bond is longer than the other four. Further details about Fe(R2C fc)2 are scarce, as the compounds are air-sensitive and rapidly oxidise to Fe(III) complexes. 

More recently, liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) have been evaluated as possible alternative methods for carfentrazone-ethyl compounds in crop matrices. The LC/MS methods allow the chemical derivatization step for the acid metabolites to be avoided, reducing the analysis time. These new methods provide excellent sensitivity and method recovery for carfentrazone-ethyl. However, the final sample extracts, after being cleaned up extensively using three SPE cartridges, still exhibited ionization suppression due to the matrix background for the acid metabolites. Acceptable method recoveries (70-120%) of carfentrazone-ethyl metabolites have not yet been obtained. 

Storage stability studies for carfentrazone-ethyl compounds on crop matrices have shown a pattern of stability for at least 7-24 months, depending on the study program or the maximum sample storage interval for the study. Carfentrazone-ethyl was not stable in field corn starch, potato tuber and bovine kidney. The residue results indicated that a significant portion of carfentrazone-ethyl was converted to C-Cl-PAc in these matrices however, the total amount of carfentrazone-ethyl and C-Cl-PAc accounted for the original spiking level. Since both carfentrazone-ethyl and C-Cl-PAc were determined in these stability studies, the instability of carfentrazone-ethyl was not of any concern. 

The bis[l,2]-dithiolo[l,4]thiazines prepared by Rees and co-workers are nonplanar, with the thiazine ring 34° out of plane for the W-ethyl compound. This gives a scorpion-like conformation with the N-substituent as the scorpion tail, seen in the crystal structure of this and other analogues <1998JOC2189>. 

The same difference in color can be observed between the dimethyl compound (P.R.179) which is red and the corresponding diethyl derivative affording a black color. According to X-ray diffraction studies the dimethyl compound consists of a parallel arrangement of molecules in stacks, whereas in the ethyl compound the molecules are in stacks twisted with respect to one another with considerably more overlapping of the perylene ring system in neighbouring molecules [5]. 

Fig. 23 Plot of C-OX bond length versus pKUO for 1-phenylethyl and l-(4-nitrophenyl)ethyl compounds [108], The error bars represent two standard deviations in the bond-length measurements, and the numbers accompanying each point are mean values of the torsional angle 8 [110] for the structure concerned. Reprinted with permission from Edwards et al. (1986a). Copyright 1986 American Chemical...

Siddall and his co-workers (46) have examined the barriers to rotation of a series of 2,6-disubstituted anilides. Af-Ethyl-A/-(2,6-xylyl)formamide (9) was recrystallized as a uranyl nitrate complex, and one isomer, which at equilibrium was favored by a factor of 3 1, was enriched up to a 30 1 ratio. The kinetics of rotation were examined at 0 to 29°C. The Arrhenius activation energy was 26 3 kcal/mol and log A was 18.5 2.4 hr-1. Siddall and Gamer (47) were able to obtain an almost pure isomer (which also predominated at equilibrium 1.3 1 for the ethyl compound and 1.1 1 for the methyl compound) of Ar-alkyl- V-(2-methyl-4,6-dibromophenyl)-l-naphthamide (10). The half-lives of... 

Figure 5.12 Melting and boiling points of compounds with substitution groups (a) methyl compounds (b) ethyl compounds...

Alkylation of silyloxy-furazan derivative (20) with triethyl orthoformate yields a mixture of 2-ethyl-l,2,5-oxadiazol-3(2//)-one (21) and O-ethyl compound (22) (Equation (1)) <93T5905> compound (21), which was characterized by its distinctive spectroscopic properties, is a rare example of a tricoordinate A-substituted 1,2,5-oxadiazole. 

The enantioselective a-alkylation of /i-oxo esters, e.g., 2-methoxycarbonyl-l-oxoindane and 2-methoxycarbonylcyclohexanone, with optically active alkyl or aryl(cthyl)methyIselenonium and -sulfonium camphorsulfonates or perchlorates, which possess a stereogenic center at the selenonium or sulfonium group, led to a mixture of a-methylated and a-ethylated compounds (Table l)7-10. 

There have been a few research papers reporting the use of other vapour generation techniques to volatilize analytes that form unstable hydrides, or had previously been thought not to form vapours at room temperature. Examples include the use of sodium tetraethylborate to form volatile ethyl compounds of cadmium, lead and thallium. 

---