Sodium, anions

The Jackson modification involves cyclisation of iV-tosylated amine 12 and provides a complementary method to the classical Pomeranz-Fritsch reaction for entry into the fully unsaturated ring system 13. Amine 12 can be prepared from either the Pomeranz-Fritsch-Bobbitt imine 10 or reaction of benzylhalide 14 and the corresponding sodium anion 15. ... 

This methodology was applied to a two-step sequence for the preparation of enantio-merically enriched dihydrobenzo[h]furans (Scheme 10.11) [46]. Rhodium-catalyzed allylic etherification of (S)-47 (>99% ee), with the sodium anion of 2-iodo-6-methyl-phenol, furnished the corresponding aryl allyl ethers (S)-48/49 as a 28 1 mixture of regioisomers favoring (S)-48 (92% cee). Treatment of the aryl iodide (S)-48 with tris(trimethylsilyl)silane and triethylborane furnished the dihydrobenzo[h]furan derivatives 50a/50b as a 29 1 mixture of diastereomers [43]. 

Substitution of the nine position is a common transformation for acridines. An optimized method for preparing the 9-carboxamides uses BOP/DMF <99SC4341>. Reaction of 9-isothioacridines with the sodium anion of diethylmalonate is followed by alkylation with bromoacetate to afford the spiro[dihydroacridine-9(10i/)-thiazolidines] <99H(51)137>. 

Paalme et al. (1990) studied the bulk deposition chemistry in the environment around the Estonian oil shale combustion area (Fig. 11 see also Kirso et al. 2002). Cations (i.e., calcium, potassium, sodium), anions (i.e., chloride, sulphate, nitrate), and - he x an e-e x t ractable PAHs were analysed in snow meltwater samples collected from 21 sampling stations in northeastern Estonia. It was found that the characteristic products of oil shale combustion, that is, Ca2+ and SC>4, accounted for over 92% of the major cations and 90% of the major anions in the snow. Correlation coefficients of r = 0.86 and 0.92 were noted for Ca2+ vs. SO - and Ca2+ vs. (SO2 - + 20 ), respectively. A high degree of correlation (r = 0.83) was also noted between Ca2+ vs. total PAHs in snow samples taken 150 km to the south of the thermal power plants. The deposition fluxes of Ca2+ and PAHs decreased with distance from the power plants. The average Ca2+ deposition flux 90 km... 

The sodium anion of trimethylsilyl diazomethane has also been used to open W-acyl (3-lactams 114, Scheme 38. The resulting intermediate a-diazoketones... 

Scheme 38 P-lactams opening with the sodium anion of TMSCHN2...

The displacement of halogens with thiolate anions is much accelerated under microwave irradiation. 2, 3-, and 4-Halopyridines react with the sodium anion of thiophenol and ethanethiol in high yield in HMPA or NMP in a matter of minutes under microwave irradiation at 110°C <2002T4931>. 

Alkylation of allylic carbonates.1 In an atmosphere of CO, this salt catalyzes the alkylation of allylic carbonates with the sodium anion of diethyl malonate. The reaction occurs selectively at the carbon substituted by the leaving group with retention of configuration of the double bond. The reaction involves net retention of configuration, possibly by two consecutive SN2 reactions. 

The sulfone moiety is a good acidifying group, so (methylsulfanyl)methyl sulfones 410 and 411 can be deprotonated and mono- or dialkylated with sodium hydroxide under PTC conditions or with sodium hydride619-622. The alkylated products can be easily hydrolyzed with hydrochloric acid in refluxing methanol, having been applied to the synthesis of acyclic and cyclic ketones. The acylation of compound 410 derived sodium anion has been performed with esters620. For the lithiation of a-thiosulfones 411622 and 412, n-BuLi, f-BuLi or LDA at —78 °C can be used. 

Oxetanes. The reaction of ketones with 3 equiv. of the sodium anion (2) of 1 results in exclusive or predominant formation of the thermodynamically more stable oxetane. For example, axially C—O-bonded oxetanes such as 3 are formed from unhindered cyclohexanones. The reagent 1 can therefore serve as a CH,CH, synthon. Thus reaction of 3 with aqueous HC1 in THF yields a single homoallylic alcohol (4). It (3) is converted into the alcohol 5 in 93% yield on hydroboration followed by oxidation. The oxetane ring is opened by a few other nucleophiles [C6H5SNa, HMPT, (CH3)2CuLi], but is inert to several other nucleophiles, such as QH5SCH2Li and LiCH2C02C(CH3)3. 

James L. Dye et al. Cryptated sodium cation and sodium anion... 

Oxetanes. The sodium anion (Z) of this sulfoximine reacts with ketones to form epoxides (3) in good yield. Welch and Prakasa Rao now report that in the reaction of ketones with an excess of 2 at elevated temperatures intermediate epoxides undergo ring expansion, with formation of the corresponding oxetane derivative. 

Treatment of cycloalkenes 15 with dimethyl(methylthio)sulfonium tetrafluoroborate (DMTSF) in acetonitrile210,211, followed by evaporation of the solvent, addition of dimethylformamide to the residue and further addition of the sodium anion of 6-amino-4-chloropurine provides owu-2-methylthio nucleoside analogs 16 in moderate yield with total diastereoselectivity212. 

Compound (97) crystallized as a dimeric, bis-THF-solvated adduct with two different types of lithium atoms, illustrated as (99). ° Compound (98) is a doubly lithium bridged dimer chelated with one TMEDA per lithium atom and roughly depicted as (1(H)).In the solid state, the sodium anion of (101) is monomeric with some of the relevant structural parameters shown in formula (102). ... 

A variety of heterocyclic systems afforded the iV-aryl derivatives. 120,129-132 fyne intermediates were sometimes involved. Indeed, the reaction of the sodium anion of 5-phenyltetrazole (37) with di-/7-tolyliodonium bromide gave the two 1,5- and 3,5-diarylated derivatives as mixtures of meta- and para-io y regioisomers in a 1 1 ratio. 29... 

FIGURE 20.15 Crystals of a salt compased of sodium anions and a complex of sodium cations. 

After being ingested, the V. cholerae organisms attach to the brash border of the intestinal epithelium and secrete an exotoxin that binds irreversibly to a specific chemical receptor (Gmi ganglioside) on the cell surface. This exotoxin catalyzes an ADP-ribosylation reaction that increases adenylate cyclase activity and thus cAMP levels in the enterocyte. As a result, the normal absorption of sodium, anions, and water from the gut lumen into the intestinal cell is markedly diminished. The exotoxin also stimulates the crypt cells to secrete chloride, accompanied by cations... 

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