Sodium thiophenoxide

Fluoro- or 2,2-difluoro-l-bromoalkanes readily undergo nucleophilic substitution in the presence of sodium thiophenoxide [45] (equation 41)... 

The above product was dissolved in dimethylformamide (65 ml), sodium thiophenoxide (0.89 g) was added thereto, and the resultant mixture was stirred at room temperature for 1 hour. To the resultant mixture, acetone (650 ml) was added, and the separated crystals were collected by filtration and washed with acetone and ether in order to give the objective compound in the form of the sodium salt (1.3 g). 

I n the above procedure, the use of 4-hydroxy-1,5-naphthyridine-3-carbonyl chloride in place of 4-hydroxy-1,5-naphthyridine-3-carboxyllc acid N-succinimide ester can also afford the same objective compound as above. The use of sodium thio-n-propoxide in place of sodium thiophenoxide can also give the objective compound in the form of the sodium salt. 

Nucleophilic substitution reactions in the selenophene series have attracted some interest. Debromination of bromonitro compounds [(50, X = S, Se) and (53, X = S, Se)] with sodium thiophenoxide and sodium selenophen-oxide72 was studied. Selenophene compounds were four times more reactive than the thiophene derivatives. The position of attack, a or /), had very little influence on the rate ratio. The kinetics of the side-chain nucleophilic reactions of selenophene derivatives, shown in Scheme 4, has been reported.7 3... 

Oximes 509 can be converted to their tosylates 510, but use of a large excess of KOH converts them directly into 27/-azirincs 511 (Scheme 82) <2003JOC9105>. The benzotriazolyl moiety in azirines 511 can be substituted by nucleophiles (organomagnesium reagents, potassium phthalimides, and sodium thiophenoxide) to give disubstituted azirines 512. 

In the presence of sodium thiophenoxide, elemental sulfur reacts with 4 or 1 to afford 1,2,4,5-tetrathianes. Huisgen116 suggested a mechanism where the oligothiolate species PhSx attacks the thione carbon as an initial step. 

Herriott and Picker (1975) have studied the reaction between sodium thiophenoxide and 1-bromobutane in benzene-water catalysed by various quaternary ammonium salts and by the dicyclohexyl-18-crown-6 isomers ([20] + [21]). The catalytic activities, as judged from the second-order rate constants, span a range of 104. The best catalyst appeared to be dicyclohexyl- 18-crown-6, directly followed by tetrabutylphosphonium chloride and tetrabutylammonium iodide. 

Table 12 The primary nitrogen ku/k15 and secondary a-deuterium KIEs for the SN2 reactions between several p-substituted sodium thiophenoxides and benzyldimethylphenylammonium nitrate in DMF at 0°C. ...

Table 13 The secondary a-deuterium and primary nitrogen KIEs and Hammett p values for the SN2 reaction between sodium thiophenoxide and benzyldimethyl-phenylammonium nitrate at different ionic strengths in DMF at 0°C. ...

For instance, (kH/kD)a was 1.085 0.011 when the sodium thiophenoxide concentration was 0.0086 mol dm-3 and 1.129 0.010 when the concentration of the sodium thiophenoxide was reduced to 0.0040 mol dm-3 in DMF at 20°C. Conductivity and UV studies of sodium thiophenoxide solutions in DMF, in DMSO, in methanol and in diglyme, and reactions done in the presence of the macrocyclic polyether 15-crown-5 (Westaway and Lai, 1988), showed that the change in the secondary a-deuterium KIE was due to a change in the form of the reacting nucleophile from a solvent-separated ion-pair complex at the higher concentration (see (27)) to a free ion at the lower concentration. 

Fig. 15 The relative transition state structures for the ion-pair SN 2 reactions between sodium thiophenoxide and benzyldimethylphenylammonium nitrate in DMF and in methanol. Reproduced, with permission, from Westaway (19%).

The secondary alpha deuterium and primary leaving group nitrogen kinetic isotope effects (Table 16) were determined for the ion-pair Sw2 reactions between sodium thiophenoxide and benzyldimethylphenylammonium nitrate in DMF at 0 °C60 and in methanol at 20 "C64 to learn how a change in solvent affects the structure of the Sp2 transition state. 

Fully conjugated species are somewhat rare in the 1,2-thiazine class of heterocycles. These molecules are comprised of two separate subclasses, the first of which includes the highly reactive 1,2-thiazinylium salts. Although these salts, such as 27, have in some cases been isolated, they readily react regioselectively at C-6 with a variety of nucleophiles including sodium alkoxides 76, silyl enol ethers 77, sodium malonates 78, and sodium thiophenoxide 79 (Scheme 10) <2001T8965>. 

Reaction of 6,7-difluoro-8-phenylsulfonyl-l,2,3,4-tetrahydropyrido[2,3- ]pyrazine 206 with sodium thiophenoxide... 

The successful application of the Hammett equation to methanolysis of 2-chloro-5-X-methylselenophenes,284 and debromination by sodium thiophenoxide of 2-bromo-5-X-3-nitroselenophenes (EtOH, 20°)275 is also reported. In the latter case p is 3.15 cf. 3.21 for the equivalent thiophene reaction. 

Addition of sodium thiophenoxide to 86 in aqueous medium furnishes trans-6-phenylthiocyclohexa-2,4-dienol (232) in 64% yield. The reaction with l,2,3,4,5-Dj-(86) established that the addition of PhS proceeds by direct trans 1,2 ring opening. Similarly, the addition of thioethanol and thioacetates to 86 proceeds by 1,2 ring opening and trans-(234) is formed.144 Reaction of 86... 

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