2- ethyl group

The removal of the two alkyl groups comprises the two primai y steps, the abstraction of the ethyl group being the dominant one. These products show up first, as can be seen on the left-hand side of Figure 10.3-14, It can also be seen that it is expected that after one year an apprceiable amount of s-triazine eom-pounds will still be found in the soil. 

Ketonic Hydrolysis. Hot dilute caustic alkalis or hydrochloric acid first hydrolyse off the ethyl group, and then remove carbon dioxide, a mono- or di-substituted acetone being thus obtained ... 

Synthesis This was in fact done by a minor variation on our strategy, the ethyl group being added later ... 

At first, the dimeric nature of the base isolated from 3-ethyl-2-methyl-4-phenylthiazolium was postulated via a chemical route. Indeed the adduct of ICH, on a similar 2-ethylidene base is a 2-isopropylthiazolium salt in the case of methylene base it is an anilinovinyl compound identified by its absorption spectrum and chemical reactivity (45-47). This dimeric structure of the molecule has been definitively established by its NMR spectrum. It is very similar to the base issued from 2.3-dimethyl-benzo thiazolium (48). It corresponds to 2-(3 -ethyl-4 -phenyl-2 -methylenethiazolinilydene)2-methyl-3-ethyl-4-phenylthiazoline (13). There is only one methyl signal (62 = 2.59), and two series of signals (63= 1.36-3.90, 63= 1.12-3.78) correspond to ethyl groups. Three protons attributed to positions T,5,5 are shifted to a lower field 5.93, 6.58, and 8.36 ppm. The bulk of the ten phenyl protons is at 7.3 ppm (Scheme 22). 

The of mesomethyl-substituted trimethine thiazolo dyes is shifted by 30 nm toward shorter wavelength. The shift is only of 20 to 25 nm for an ethyl group, whereas phenyl has no effect. 

The mass spectra of more substituted thiazoles, or those with larger alkyl groups are more complex and involve other fragmentation patterns (117, 118, 374). The molecular ion is still abundant but decreases with increasing substitution past the ethyl group. 

The compound becomes an octane derivative that bears a C 3 methyl group and a C 4 ethyl group When two or more different substituents are present they are listed m alphabetical order in the name The lUPAC name for this compound is 4 ethyl 3 methyloctane... 

The alkane bears two methyl groups and an ethyl group It IS an ethyldimethylhexane... 

Excluding compounds that contain methyl or ethyl groups write structural formulas for all the bicychc isomers of (a) CsHg and (b) CgHjo... 

At first glance splitting may seem to complicate the interpretation of NMR spectra In fact It makes structure determination easier because it provides additional information It tells us how many protons are vicinal to a proton responsible for a particular signal With practice we learn to pick out characteristic patterns of peaks associating them with particular structural types One of the most common of these patterns is that of the ethyl group represented m the NMR spectrum of ethyl bromide m Figure 13 15... 

FIGURE 13 15 The 200 MHz H NMR spectrum of ethyl bromide (BrCH2CH3) showing the char acteristic triplet-quartet pattern of an ethyl group The small peak at 8 1 6 is an impurity... 

Section 13 8 The methyl protons of an ethyl group appear as a triplet and the meth ylene protons as a quartet in compounds of the type CH3CH2X... 

H NMR spectrum of 2 butanone The triplet-quartet pattern of the ethyl group IS seen more clearly in the expanded scale insets... 

The carbon-oxygen bond broken m the process is therefore the one between oxygen and the acyl group The bond between oxygen and the ethyl group remains intact An 8 2 reaction at the ethyl group would have broken this bond... 

NMR Chemical shift differences m their H NMR spectra aid the structure deter mmation of esters Consider the two isomeric esters ethyl acetate and methyl propanoate As Figure 20 9 shows the number of signals and their multiplicities are the same for both esters Both have a methyl singlet and a triplet-quartet pattern for their ethyl group... 

Ether (Section 16 1) Molecule that contains a C—O—C unit such as ROR ROAr orArOAr Ethylene (Section 5 1) H2C=CH2 the simplest alkene and the most important industnal organic chemical Ethyl group (Section 2 13) The group CH3CH2—... 

Rule 2. When atoms attached directly to a double-bonded carbon have the same priority, the second atoms are considered and so on, if necessary, working outward once again from the double bond or chiral center. For example, in l-chloro-2-methylbutene, in CH3 the second atoms are H, H, H and in CH2CH3 they are C, H, H. Since carbon has a higher atomic number than hydrogen, the ethyl group has the next highest priority after the chlorine atom. 

For linear alkanes, the initial fragment lost is an ethyl group (never a methyl group), followed by propyl, butyl, and so on. An intense peak at mass 43 suggests a chain longer than butane. 

Strauss and Williamst have studied coil dimensions of derivatives of poly(4-vinylpyridine) by light-scattering and viscosity measurements. The derivatives studied were poly(pyridinium) ions quaternized y% with n-dodecyl groups and (1 - y)% with ethyl groups. Experimental coil dimensions extrapolated to 0 conditions and expressed relative to the length of a freely rotating repeat unit are presented here for the molecules in two different environments ... 

Alkylation of the amino group to a mono- or dialkyl form strengthens the uv absorption and also increases the wavelength of the fluorescent light two alkyl groups are more effective than one and ethyl groups are more powerflil than methyl groups. 

Exclusion of light prevents attack of chlorine on the ethyl groups. 

The Tatoray process, which was developed by Toray Industries, Inc., and is available for Hcense through UOP, can be appHed to the production of xylenes and benzene from feedstock that consists typically of toluene [108-88-3] either alone or blended with aromatics (particularly trimethylbenzenes and ethyl-toluenes). The main reactions are transalkylation (or disproportionation) of toluene to xylene and benzene or of toluene and trimethylbenzenes to xylenes in the vapor phase over a highly selective fixed-bed catalyst in a hydrogen atmosphere at 350—500°C and 1—5 MPa (10—50 atm). Ethyl groups are... 

Another important development in the stmcture—activity relationships of quinolone antibacterials came with the introduction of the 1,8-bridged quinolone ofloxacin (6a). In this quinolone, the movement of the ethyl group at the 1-position is restricted by "tying" it to the 8-position in the form of a 1,4-benzoxazine ring. In vitro activity improvements are found that are more or less comparable to the improvements noted with ciprofloxacin (35,41—43). 

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