Silver /?-Toluenesulfonate

O-acetylophiocarpine (381) with ethyl chloroformate afforded the C-8—N cleaved urethane 382 in quantitative yield. Sequential treatment of 382 with silver nitrate, PCC, sodium hydroxide, and p-toluenesulfonic acid in ethanol furnished acetal 384, which was reduced with lithium aluminum hydride followed by hydrolysis to afford the hemiacetal 385. Oxidation of 385 with PCC provided (+ )-a-hydrastine (369). Similar treatment of O-acetylepi-ophiocarpine (386) afforded ( )-/J-hydrastine (368) however, in this case, C—N bond cleavage of 386 with ethyl chloroformate proceeded without regioselectivity. 

Further, a very recent paper has reported a cascade rearrangement, under acidic conditions of the simpler educt, a dispiro[3.0.3.3]undecane derivative 93 to the dehydrated isomeric propellane 94 40). It is somewhat reminiscent of the analogous case of 26 where silver ion is the catalyst10). Treatment of the dispiro-alcohol 78 when heated for 2 hrs at 70 °C with p-toluenesulfonic acid in benzene gives in quantitative yield the [3.3.3]propellene 94. The following cascade is proposed to explain the rearrangement. 

The cydization can also be carried out on a-tosylaminoallenes, in which case the choice of reaction conditions determines whether the product is the N-tosyl-3-pyrro-line or whether elimination of toluenesulfonic acid acid gives the pyrrole. For example, in the presence of catalytic silver nitrate, allene 141 (Eq. 13.47) rearranges to N-tosylpyrroline 142 in excellent yield, whereas when 141 is treated with potassium tert-butoxide in DMSO, pyrrole 143 is formed in 71% yield [54]. Warming the lithium salt of 141 in DMSO also leads to 143. The rearrangement of 141 to 143 may be mechanistically related to the conversion of 130 to 131 (Eq. 13.42). 

Other polymerisation incidents are f Acrylaldehyde, 1145 Acrylamide, 1180 Acrylic acid, 1148 Acrylic acid, Initiator, Water, 1148 f Acrylonitrile, 1107 f Acrylonitrile, Initiators, 1107 f Acrylonitrile, Silver nitrate, 1107 f Acryloyl chloride, 1093 Allyl 4-toluenesulfonate, 3315 Aluminium chloride, Alkenes, 0062 3 - Aminopropiononitrile f Aziridine, Acids, 0863... 

Tetrahydro[l,3]thiazino[3,2-6]isoquinolin-6-one was formed when iV-(3-mercaptopropyl)homophthalimide was heated in o-dichlorobenzene in the presence of p-toluenesulfonic add at 120°C (78BEP866987, 78GEP2756067 79CPB2372). Treatment of jV-(o-acetylthioxybenzoyl)-valerolactam with silver acetate and pyridine in methanol gave 5a-hydroxypyrido[2,l-h][l,3]benzothiazin-ll-one (25) (68AG909). 

C.) at concentrations below 5 X 10"5M. The p-toluenesulfonate (pts) salt of this cyanine was also used it gave identical surface spectra and adsorption data in silver and silver halide dispersions (23). Astra-phloxin (55) (l,l -diethyl-3,3,3, 3 -tetramethylindocarbocyanine pts,... 

Apparently, the first use of this reaction in the sugar series was in the preparation33 of tetra-0-acetyl-l-0-tosyl- a -D-glucopyranose (probably the /3-derivative actually, by Walden inversion at carbon atom 1) by the action of silver p-toluenesulfonate on tetra-O-acetyl-a-D-glucopyranosyl bromide in boiling, dry diethyl ether ... 

Despite the fact that 2,4,6-tri-0-acetyl-3-0-tosyl-a-D-glucosyl bromide reacts86 with silver p-toluenesulfonate in pyridine to give a glucosyl-pyridinium p-toluenesulfonate (see, also, p. 120), it is claimed237 that treatment of 3,4-di-0-acetyl-2,6-di-0-tosyl-a-D-glucosyl bromide with silver acetate in pyridine (at 50° for only 2 minutes) affords 1,3,4-tri-O-acetyl-2,6-di-0-tosyl-/3-D-glucose. 

Sulfonic acids add to alkenes and alkynes. The reaction of an alkyne with ara-toluenesulfonic acid and treatment with silica gives the vinyl sulfonate (C=C—OS02To1) Cyclic sulfonates can be generated by the reaction of an allylic sulfonate salt (C=C—C—OSOs ) with silver nitrate in acetonitrile containing an excess of bromine and a catalytic amount of water. Sultones are formed when alkenes react with PhlO and two equivalents of Me2SiS03Cl. ... 

Kornblum and co-workers prepared the reagent quantitatively by mixing equivalent amounts of silver oxide and p-toluenesulfonic acid monohydrate in acetonitrile (with protection from light). After one-half hour silver chloride was removed by filtration and the filtrate was evaporated to dryness. 

Silver oxide, 527, 558, 683, 1011-1015 Silver perchlorate, 1187 N-Silver succinimide, 510 Silver sulfate, 1615 Silva tetrafiuoroborate 1015-1618 Silver p-toluenesulfonate, xe Silver to late Silver tosylate, 303,737,1618 Silva tfifluoroacetate, 495, 504,1618-1019, 1220,1227... 

The reagent is prepared by reaction of silver p-toluenesulfonate with p-nitrobenzyl bromide (88% crude, 80% pure). It reacts with the sodium or trialkylammonium salt of a carbobenzoxy amino acid or peptide in acetone or dimethylformamide to give the p-nitrobenzyl ester in high yield. The protective group is stable to acid and readily removed by catalytic hydrogenation. 

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