Alkyl sulfates isolation

Alkyl sulfates, tosylates, and other esters of sulfuric and sulfonic acids can be converted to alkyl halides with any of the four halide ions.979 Neopentyl tosylate reacts with Cl, Br, or I without rearrangement in HMPA.980 Similarly, allylic tosylates can be converted to chlorides without allylic rearrangement by reaction with LiCl in the same solvent.981 Inorganic esters are intermediates in the conversion of alcohols to alkyl halides with SOCl2, PC15, PC13, etc. (0-67), but are seldom isolated. 

There are several problems requiring careful attention. Lysozyme has a tendency to form complexes with many substances [e.g., alkyl sulfates, fatty acids, aliphatic alcohols (Smith and Stocker, 1949), cephalins (Brusca and Patrono, 1960), and other proteins]. Of particular importance is its tendency to form complexes with transferrins [e.g., ovotrans-ferrin (Ehrenpreis and Warner, 1956)]. These interactions lead to difficulties in the isolation of lysozyme. Some recent workers have used fast protein liquid chromatography (FPLC) and high-performance liquid chromatography (HPLC) (e.g., Ekstrand and Bjorck, 1986). The resolution in these procedures may not always be satisfactory, and in HPLC pressure and solvent effects must be monitored carefully if the product is to be suitable for conformation and activity studies. 

Lower dialkyl sulfides and vinyl sulfides293 are advantageously prepared by alkaline hydrolysis of S-alkylthiouronium salts, the resulting thiolate being alkylated, without isolation, by an alkyl halide or dialkyl sulfate.294... 

There are two obvious limitations to the use of surfactants in preparative chemistry. The first is that the high molecular weight of surfactants makes it impracticable to use them in large excess over reactants, and second, surfactants complicate product isolation. The isolation problem can often be solved by precipitating the surfactant, e.g., alkyl sulfates can often be precipitated from water as their potassium salts, or alkylammonium ions as their perchlorates, but both limitations are neatly solved using the two-phase system of phase-transfer catalysis. 

Oreganic acid (Figure 16), a tricarboxylated alkyl sulfate, was isolated from an endophytic fungus that inhabited living leaves of Berberis oregana, collected from Humboldt Co., California. Like the other compounds described above, isolation of this highly charged compound was accomplished in two steps by gel filtration followed by reverse phase HPLC [89]. The structure of the compound was established by the application of NMR and mass spectroscopy [89]. 

Quatemization involves the reaction of a tertiary amine with an alkylating agent. Typically, primary and some secondary alkyl halides are used for this purpose, although alkyl sulfates have also been used. Tertiary hahdes are not useful because they undergo elimination rather than substitution. The reaction, which is an example of an Sn2 process, proceeds readily to give crystalline, stable, and still-aromatic quaternary salts (Scheme 6.6). These have been used for many years to characterize amines. Acyl halides also react in a similar manner with pyridine, but the resulting salts are unstable and generally not isolated. 

There are a number of standard methods for this analysis, for example, ASTM D1568 for alkylaryl sulfonates, ASTM D1570 for analysis of alkyl sulfates, ISO 1104 for alkane-sulfonates and certain non-LAS alkylarylsulfonates, and ASTM D3673 for a-olefin sulfonates (6-9). As with any extraction, it is advisable to check the isolated oil by IR... 

Where X is Br or Q, the free acids may be obtained by acidification of the alkaline solution, but where X is I, the acids must be isolated as salts to avoid reduction of the arsonic acids by HI. Rather than using alkyl haUdes, alkyl or dialkyl sulfates or alkyl arenesulfonates can be used. Primary alkyl haUdes react rapidly and smoothly, secondary haUdes react only slowly, whereas tertiary haUdes do not give arsonic acids. AHyl haUdes undergo the Meyer reaction, but vinyl hahdes do not. Substituted alkyl haUdes can be used eg, ethylene chlorohydrin gives 2-hydroxyethylarsonic acid [65423-87-2], C2H2ASO4. Arsinic acids, R2AsO(OH), are also readily prepared by substituting an alkaU metal arsonite, RAs(OM)2, for sodium arsenite ... 

Alkylation with a vatiety of common alkyl halides oi sulfates gives stable dialkylcyanamides. However, the intermediate monoalkylated compounds usually cannot be isolated and cychc trimers or cotrimers with cyanamide ate obtained (13). The reaction can be carried out efficientiy in water or alcohol. Allyl chloride is an especially useful reagent, producing diallylcyanamide [538-08-9J (4). 

The indol-3-yl-substituted indolo[2,3-()]carbazole 143 has been isolated as a product from the complex mixture generated by the decomposition of urorosein (144) (99CHE561). Interestingly, when subjected to alkylation conditions involving sodium hydride and dimethyl sulfate in THF, 143 was transformed into the N. -dimethyl derivative 145 in 36% yield (00MI2). 

The pathways for the degradation of toluene and xylene under denitrifying and sulfate-reducing conditions have been studied most extensively, and they take place by reactions quite different from those used by aerobic bacteria. As an example, two anaerobes affiliated with known sulfate-reducing bacteria isolated from enrichments with crude oil were able to grow at the expense of a number of alkylated benzenes—strain oXySl with toluene, o-xylene, and o-ethyltoluene and strain mXySl with toluene, m-xylene, and m-ethyltoluene (Harms et al. 1999). 

Conventional alkylating agents (alkyl halides, sulfates, etc.) are rather rarely used in the synthesis of alkyl nitronates. This is associated with relatively low reactivity of these compounds which, combined with low thermal stability of nitronates (for more details, see Section 3.3.1.1), does not allow one to isolate target products in the individual state. 

Benzylquinoxaline (62) is the only product isolated from the homolytic benzylation of quinoxaline with dibenzyl mercury.73 Gardini and Minisci found that homolytic alkylation,74 acylation,75 cr-oxy-alkylation,76 carboxylation,77 and <5-aminoalkylation78 of quinoxaline always gave the 2-substituted product. When a mixture of quinoxaline and ferrous sulfate is treated with A-chlorodi-n-butylamine, exclusive 2-substitution occurs in 50% sulfuric acid, but in concentrated acid a... 

Alkylation of l,2,4-triazine-3,5-diones (33) with methyl iodide begins at N-2 (182a), while dimethyl sulfate or diazomethane convert (33) initially into the 4-methyl derivatives (183a). In all cases 2,4-dimethyl-l,2,4-triazine-3,5-diones (184a) were isolated on further alkylation <78HC(33)189, p. 327). 

Despite the great number of metal-carbamates isolated to date, the transfer of a carbamic group from a metal center to an alkylating agent such as an alkyl halide or diatkyl sulfate has been documented in only a few cases [1, 2]. 

Several sulfated polyhydroxysterols have been recently isolated from sponges. Most of these natural products are characterized by the 2p,3a,6a-tri-0-sulfate functions together with additional alkylation in the side chain. These steroids are of interest not only because of their structures but... 

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