Ester sulfate, formation

Sulfated zirconia, 5 331-333 Sulfate esters, 23 653 Sulfate formation, on Claus catalysts, 23 610-614... 

Organic sulfur is the dominant form in peats described in these studies. Pyrite, however, is abundant in brackish and marine peats, occurring in void spaces in or between plant debris (3). In a study of pyrite formation in freshwater peats, Altschuler et al. (5) determined parallel decline in ester sulfate with increases in pyrite as depth increased and concluded that pyrite formed at the expense of organic sulfur. In general, framboidal morphology is present at all salinities. Altschuler et al. (5) and Lowe and Bustin (10) found monosulfides to be minor in peats. 

Another conjugative reaction, particularly of phenolic hydroxyl groups, is ethereal sulfate formation. The cytosol portion of liver cells contains enzymes that activate sulfate to a form transferrable to acceptors. Thus 3 -phosphoadenosine-5 -phosphosulfate (PAPS) will sulfate phenols to ethereal sulfates (actually half-esters of sulfuric acid), thus increasing their polarity and excretability greatly (Fig. 3-3). 

The presence of the sulfuryltransferase system for the formation of steroid ester sulfates has been demonstrated in different human and animal tissues (adrenals, liver, kidneys, skin, etc.). Phese steroid ester sulfates act in the intermediate metabolism of steroids and undergo extensive qualitative and quantitative variations during life development and also in some physiopathologicai conditions. On the other hand, steroid glucuronides generally represent the final step in the metabolism of steroids. 

Testosterone produced by the placenta is transferred to the fetus and is conjugated mainly with sulfuric acid, but in contrast to a high sulfatase activity by the placental tissues for ester sulfates of 3/J-hydroxy-As steroids and for estrogen sulfates, the testosterone sulfate is poorly hydrolyzed by placental tissues (French and Warren, 1966). These results confirm that the sulfatase activity in the placental compartment is conditioned by the structure of the sulfate. In addition, the incubation of testosterone sulfate with a placental microsomal preparation failed to show any formation of estrogens (Cheatum et at., 1968). These last results also agree with the absence of aromatization of testosterone sulfate during pregnancy (Baulieu ef al., 1965). 

Placental estriol is biosynthesified from fetal lOa-hydroxydehydroepi-androslerone which reaches the placenta oi the form of ester sulfate (see Section III, 2, a), Androstcnetriol also reaches the placenta from the fetus in the form of ester sulfate and contributes to the formation of e.striol. 

Since in placental tissues there is an important suifata-se activity and since the fetal compartment is very active in the formation of steroid ester sulfates, most of tlie steroids transferred from tlie fetus to the placenta are ester sulfates, and vice versa, most of the steroids which cross from the placenta to the fetus are in unconjugated form. 

Formation of esters of inorganic acids (Section 15 9) Alkyl nitrates dialkyl sulfates trialkyl phos phites and trialkyl phosphates are examples of alkyl esters of inor game acids In some cases these compounds are prepared by the direct reaction of an alcohol and the inorganic acid... 

Glucuronidation. Complexation of the steroid to glucuronic acid, most predominantiy via the C-3 hydroxyl, leads to a considerable portion of the excreted metabohtes of ah. glucocorticoids. In infants, sulfurylation (formation of a sulfate ester) is also predominant (16). 

Detoxifica.tlon. Detoxification systems in the human body often involve reactions that utilize sulfur-containing compounds. For example, reactions in which sulfate esters of potentially toxic compounds are formed, rendering these less toxic or nontoxic, are common as are acetylation reactions involving acetyl—SCoA (45). Another important compound is. Vadenosylmethionine [29908-03-0] (SAM), the active form of methionine. SAM acts as a methylating agent, eg, in detoxification reactions such as the methylation of pyridine derivatives, and in the formation of choline (qv), creatine [60-27-5] carnitine [461-06-3] and epinephrine [329-65-7] (50). 

For extraction of uranium from sulfate leach Hquors, alkyl phosphoric acids, alkyl phosphates, and secondary and tertiary alkyl amines are used in an inert diluent such as kerosene. The formation of a third phase is suppressed by addition of modifiers such as long-chain alcohols or neutral phosphate esters. Such compounds also increase the solubihty of the amine salt in the diluent and improve phase separation. 

The formulation of calcium chelate materials is based upon the formation of a low-solubiUty chelate between calcium hydroxide and a sahcylate. Dycal utilizes the reaction product of a polyhydric compound and sahcyhc acid. Other sahcyhc acid esters can be similarly used. Vehicles used to carry the calcium hydroxide, extenders, and fillers may include mineral oil, A/-ethyl- -toluenesulfonamide [80-39-7] and polymeric fluids. The filler additions may include titanium dioxide [13463-67-7] zinc oxide, sihca [7631-86-9], calcium sulfate, and barium sulfate [7727-43-7]. Zinc oxide and barium sulfate are useflil as x-ray opacifying agents to ensure a density greater than that of normal tooth stmcture. Resins, rosin, limed rosins, and modified rosins may serve as modifiers of the physical characteristics in both the unset and set states. 

On digestion of this solid mass with 1 1. of ice and water, the sodium salt of the enol dissolves in the water, and the unreacted ester is removed by extracting the aqueous layer with two 200-ml. portions of ether (Note 5). The foimyl derivative settles out as an oil upon acidification of the aqueous layer with dilute sulfuric acid. The oil is extracted with three 200-ml. portions of ether, and the ethereal extract is washed several times with water and dried over anhydrous sodium sulfate. The ether is distilled, and, to remove traces of ethyl formate, the oil is heated on a steam bath under a pressure of 20-30 mm. for 1 hour. The remaining yellow formyl derivative weighs 27-29 g. (Note 6). 

The -butyl ester is a relatively hindered ester, and many of the following methods for its formation should be, and in many cases are, equally effective for the preparation of other hindered esters. The related 1- and 2-adamantyl esters have been used for the protection of aspartic acid and other amino acids (1-AdOH, toluene, dimethyl sulfate, cat. TsOH, 70-80% yield). ... 

Due to the convenience of the Wenker aziridine formation from P-aminoethyl sulfate ester (4) and base, many improvements ensued. Leighton et al. improved the yield of the first step for the formation of sulfate ester 4. First of all, both ethanolamine and 95% sulfuric acid were diluted with half of their weight of water and then slowly mixed together at 0 C. Finally, by keeping the temperature below 145 C, sulfate ester 4 was obtained in 90-95% yield. 

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