Sodium benzoate/dimethylformamide

It is of interest to note that treatment (23) of the 2,3-unsaturated analog 44 with sodium benzoate in 2V,N-dimethylformamide affords compounds 45 and 46 (3 1) with inversion at C-4. The selective formation... 

The syntheses of both l-(3-deoxy-/ -D-g/i/cm>-pentofuranosyl-2-ulose)uracil (25c) and l-(3-deoxy-/ -D-g/ /cm>-pentofuranosyl-2-ulose)cytosine (30b) by selective elimination reactions have been reported.4,5 Thus, the reaction of sulfonyl derivatives of the cytosine nucleoside 26, and uracil nucleosides 23a, 23c, and 28, with sodium benzoate in N,N-dimethylformamide (DMF) leads to 3 -deoxy-2 -ke-tonucleosides by way of such (presumed) unsaturated intermediates as 24a, 24c, 29a, and 29b. However, in one instance, the intermediate... 

In the alditol derivative 3-0-benzyl-l,2 5,6-di-0-isopropylidene-4-0-(methylsulfonyl)-n-mannitol (40), both Foster and coworkers and Baker and Haines observed intramolecular displacement by the benzoate group. Foster and coworkers employed sodium benzoate in moist, boiling N,N-dimethylformamide, whereas Baker and Haines used sodium acetate in moist iV,iV-dimethylformamide. An appreciable quantity of the Sk2 products, the 3,4-di-O-benzoyl-n-tabtol and the 4-0-acetyl-3-0-benzoyl-n-talitol derivatives, respectively, were noted in the resulting mixture. The monobenzoate fraction (42) results from attack by water on the... 

In some related work, Foster and coworkers treated the di-O-iso-propylidene-D-mannitol di-p-toluenesulfonate (43) with sodium benzoate in W,W-dimethylformamide, and obtained, among a number of other products, the di-O-isopropylidene-D-iditol monobenzoate (46) and the di-O-isopropylidene-D-talitol dibenzoate (47). A rational sequence for these two products involves first, the Sn2 displacement on (43) to give the D-talitol compound (44), that yields the orthoester ion (45) by benzoyl-group participation. Conventional attack by water at C-1 leads to (46), whereas attack by benzoate ion at C-3 leads to (47). The authors suggested that participation reactions leading to (46) and (47) were... 

Two useful syntheses of L-ribose represent applications of the benzoate inversion reaction. The protected L-arabinose derivative (57), on treatment with sodium benzoate in iV,iV-dimethylformamide for 72 hours at reflux temperature, gave a mixture that contained the monobenzoate (58) this could be further benzoylated to give a low overall yield of... 

D-lyxofuranosyladenine (62) was also accomplished, by heating (61) with sodium benzoate in iV,A -dimethylformamide, and then saponifying... 

ReckendorP< > < >) reported that the closely related compound (ISl), on reaction with sodium acetate in 95% ethanol, sodium methoxide in N, N-dimethylformamide, or sodium benzoate in iV,iV-dimethylformamide, gave a product that contained (152), as it could be hydrolyzed to 2,6-di-... 

The endo-methylsulfonyloxy groups of l,4 3,6-dianhydro-2,5-di-0-(methylsulfonyl)-D-mannitol (18, R = R = OMs) are readily displaced by sodium benzoate in N,N-dimethylformamide to give an L-iditol derivative,280 and by potassium thiolacetate in ethanol307 at 115°. As suggested by Cope and Shen,300 the thiolacetate formed very probably has L-ido stereochemistry (20, R = R = SAc), and is not the D-manno isomer originally proposed. 

Another example of a cis-fused, five-membered ring-system occurs in 3,6-anhydrohexofuranose derivatives, and 3,6-anhydro-l,2-0-isopropylidene-5-O-p-tolylsulfonyl-a-D-glucofuranose (27) contains an endo-sulfonyloxy group which can readily be displaced by sodium azide in N,N-dimethylformamide, and by hydrazine314 or sodium benzoate in 2V,2V-dimethylformamide,315 to give L-idose derivatives. 

The 2 -0-p-tolylsulfonyl derivative of 8-hydroxyadenosine underwent intramolecular sulfonate displacement when heated at 100-105° with sodium benzoate in N V-dimethylformamide, and the 2, 8-anhydro structure (170) was indicated.434 A derivative of2, 8-anhydro-guanosine (171) was obtained by a similar method.435... 

Alditol derivatives containing non-terminal double bonds have also been reported. Treatment of 1,2 5,6-di-0-isopropylidene-3,4-di-O-p-tolylsul-fonyl-D-mannitol with sodium benzoate in iV,A -dimethylformamide afforded, in addition to saturated products of displacement, 3-deoxy-1,2 5,6-di-0-isopropylidene-4-0-p-tolylsulfonyl-D-(/ireo-hex-3-enitol and the corresponding tetrol formed by hydrolysis of the acetal rings. 1,2 5,6-Di-O-isopropylidene-D-mannitol and -D-altritol have been converted into the trans and cis isomers, respectively, of 1,2 5,6-di-O-isopropylidene-3,4-dideoxy-D-(/irco-hex-3-enitol by the thionocarbonate method. ... 

Aromatic and aliphatic isocyanates can undergo self polymerization to form stable resinous trimer structures. The reaction is catalyzed by many materials including calcium acetate, potassium acetate, sodium formate, sodium carbonate, sodium methoxide, triethylamine, oxalic acid, sodium benzoate in dimethylformamide, and a large number of soluble metal... 

Reacting this with sodium methoxide leads to the formation of an epoxide— 9-(2, 3 -anhydro- 8-luxofuranosyl)adenine (36.1.9). Finally, heating this epoxide with sodium acetate or benzoate opens the epoxide ring in the dimethylformamide-water system to make the corresponding dihydroxy derivative, vidarabine [12,13]. 

A mixture of 1.6 parts of 1H-1,2,4-triazole, 54 parts of N.N-dimethylformamide and 45 parts of benzene is stirred and refluxed for 2 h. After cooling, 0.78 parts of sodium hydride dispersion 78% are added and the whole is stirred for 30 min at room temperature. Then there are added 8.9 parts of cis-2-(bromomethyl)-2-(2,4-dichlorophenyl)-l,3-dioxolan-4-ylmethyl benzoate and stirring is continued overnight at 150°C. The reaction mixture is cooled and poured onto water. The product is extracted three times with benzene. The combined extracts are washed twice with water, dried, filtered and evaporated, yielding 8.5 parts of cis-[2-(2,4-dichlorophenyl)-2-(lH-l,2,4-triazol- l-ylmethyl)-l,3-dioxolan-4-ylmethyl]benzoate as a residue. 

Although this substance is a weaker base than either sodium ethoxide or sodium phenoxide, it has much greater nucleophilic power. Sheehan and Daves- used it in dimethylformamide at or below room temperature to cleave sensitive ester functions (principally phenacyl) at the C—O bond to generate sodium salts of the corresponding carboxylic acids in good to excellent yield, as illustrated for phenacyl benzoate. The reagent is prepared by adding thiophenol to a molar proportion of... 

---