Isolation results

Additional compounds having similar biological activities and stmctural components were isolated resulting in the recognition of PGs as a family of closely related compounds. Stmctural and stereochemical assignments of PGE and PGF, were confirmed by x-ray crystallographic analysis of their... 

It has been postulated that secophthalideisoquinoline ene lactams and hydroxy lactams are most probably artifacts of isolation resulting from the reaction of enol lactones or keto acids with ammonia during the extraction process. The hydroxy lactams are probably formed initially and then undergo dehydration to give ene lactams (5,8). For this reason, this section covers the hydroxy lactams in addition to the ene lactams. The hydroxy lactams are... 

Methylbenzenes lose a proton from a methyl group to form a benzyl radical. In aqueous M-percbloric acid this reaction is fast with a rate constant in the range 10 lO s and the process is not reversible [24]. The process becomes slower as the number of methyl substituents increases, Hexaethylbenzene radical cation is relatively stable. When the benzyl radical is formed, further reactions lead to the development of a complex esr spectrum. Anodic oxidation of hexamethylbenzene in trifluoroacetic acid at concentrations greater than 1 O M yields the radical-cation I by the process shown in Scheme 6.1 [14], Preparative scale, anodic oxidation of methylbenzenes leads to the benzyl carbonium ion by oxidation of the benzyl radicals formed from the substrate radical-cation. Products isolated result from further reactions of this carbonium ion. 

V. Reactions of thianthrene radical ion(l+) with nucleophiles. As discussed previously, thianthrene radical ion(H-) reacts rapidly with water, giving thianthrene and its 5-oxide. So from most reactions that have been described, these two products are also isolated, resulting from reaction... 

The isotope first isolated resulted from beta emission by Np238. In the spring of 1941 Seaborg s group isolated a new isotope, prepared by neutron bombardment of U238. The series of reactions was ... 

Direct evidence for the existence of a tetrahedral intermediate was found by Zaugg et al.2S in the ammoniolysis of 3-(/J-bromoethyl)-3-phenyl-2-benzofur-anone (X) in acetonitrile. Approximately 10% of the trapping product XI was isolated, resulting from an intramolecular displacement of bromide ion in the tetrahedral intermediate. 

Thus it seems most probable that the isolated result of Daniels, Wulf, and Karrer was due to error rather than a real anomaly in the reaction. 

Trimethylsilyl chlorochromate, ClCr020Si(CH3)3 (1). The orange-red reagent is prepared in situ from equimolar amounts of ClSi(CH3)3 and Cr03 in CH2CI2.1 Attempted isolation resulted in a violent explosion. 

The oxidation of the primary alcohol leads to an aldehyde that is isolated as an aminal. Minor amounts of a methylthiomethyl ether are isolated, resulting from the reaction of the alcohol with CH2=S(+)-Me that is formed by thermal decomposition of activated DMSO. Interestingly, a Swern oxidation fails to deliver the desire product, because it causes the chlorination of the indole. 

Nguyen, T.T. 1999. The cholesterol-lowering action of plant stanol esters. J. Nutr. 129, 2109-2112. Ni, W., Yoshida, S., Tsuda, Y., Nagao, K., Sato, M., and Imaizumi, K. 1999. Ethanol-extracted soy protein isolate results in elevation of serum cholesterol in exogenously hypercholesterolemic rats. Lipids 34, 713-716. 

Zinc is found in a relatively low abundance in nature, but has been known for a long time due to the ease with which it is isolated from its ores. Despite the low occurrence, the ease of isolation results in today, zinc metal and zinc salts being available at low cost from the usual chemical suppliers. 

Nuclear isolation is a method by which large numbers of free intact nuclei are obtained. The method of isolation resulting in the highest yield of intact nuclei is dependent on the age and type of the particular tissue used. The method presented here5 has been demonstrated to give high yields of intact nuclei in maize, wheat, barley, oats, sorghum, and soybeans. 

H. serrata and its related genera have been used as folk herbs for the treatment of memory disorder and schizophrenia in the east of China. Phytochemical studies disclosed that these plants contained mainly serratene-type triterpenes and Lycopodium alkaloids.In the early 1970s, Chinese scientists reported that the total alkaloids of H. serrata could relax the striated muscle and alleviate the symptom of myasthenia gravis on the animal model. Biodirected assay caused the phenolic alkaloids fraction to be spotlighted and the following chemical component isolation resulted in the finding of HA. ... 

After tlie brandling point atpreplienic acid (58), plienylalaiiine and tyrosine as well as the amines (59) are not interconvertible. Finally, deamination and oxidative cleavage of tlie presumed (and in some circumstances isolated) resulting alkenes yields the equivalent of benzaldeliyde (60, R = H), C H60, and -hydroxvbenzaldehyde (60, R = OH), ie, aromatics with one aliphatic carbon attached C6—Ci fragments). 

In the reaction of hydroxyalkynes 457 with carbodiimides, oxazolidines 458 are isolated, resulting from cyclization of the initially formed isoureas. ... 

Trimethylsilyl chlorochromate (19) must be formed in situ from trimethylsilyl chloride and moist, powdered chromium(VI) oxide, since attempted isolation results in explosions. 

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