Sulfone acetals

In the reaction with epoxides, y-hydroxysulfones are obtained278-280. For example, Kondo and coworkers279 synthesized various (5-lactols 226 by treating sulfone acetals 225 with terminal epoxides as shown below. Dilithiated phenylsulfonylmethylene reacted with haloepoxide and afforded 3-(phenylsulfonyl)cycloalkanols281. Treatment of y, 5-epoxysulfones 227 and 229 with n-butyllithium resulted in cyclization to form cyclopropane derivatives 228 and bicyclobutane 230, respectively282. 

Esters (Sulfinates,Sulfonates, Acetates, Acetylenic Carboxylates) 300... 

Extract powder with aqueous 0.01M sodium heptane sulfonate-acetic acid (99 1). Flush with nitrogen. Heat to 55°C. Wash sorbent with methanol followed by above extracting solvent. Elute with methanol. 

Y-Oxo sulfone acetals can be acylated with esters giving, after reductive desulfonylation, a convenient route to y-keto aldehydes or 1,4-diketones (Scheme 67). The intermolecular acylation of a-sulfonyl carbanions was also used to synthesize 7-butyrolactones. ... 

Oxonium intermediates resulting from the pinacol rearrangement of a-sulfonate acetal derivatives can be intercepted with nucleophilic reagents, affording protected ketones or aldehydes. Rearrangement of acetals in the presence of excess bis(2-methylpropyl)aluminum hydride affords the acetal products31. 

Methyl-1,2,4-thiadiazoles (392) are accessible from the 5-chloro compounds (388) by two routes involving 5-malonic esters (see Scheme 10).287 The initial replacement (388 -> 389) is effected in good yield by the action of sodiodiethyl malonate the resulting 5-diethylmalonyl derivatives are remarkably resistant to alkaline hydrolysis, possibly because of their resonance stabilization as salts (397). Add hydrolysis, performed on a small scale under strictly controlled conditions to prevent further decomposition, produces the l,2,4-thiadiazol-5-ylacetic adds (390), and these are readily decarboxylated at 140-150°C to the 5-methyl homologs (392, R = Me, Et, Ph, SMe). Alternatively, the di-rm-butylmalonic esters (391) produce 392 in one operation on treatment with toluene-p-sulfonic-acetic adds. In contrast to previous syntheses of the 3,5-dimethyl homolog,288-290 this approach provides 5-methyl-l,2,4-thiadiazoles bearing different 3-substituents.287... 

Application of the same sequence to the sulfone acetal (5) provides a route to (E)-a, j3-unsaturated aldehydes of type (6). This sequence was used in a synthesis of ( )-nuciferal (7). 

Urine Mix sample with metha-nol/heptane sulfonate/ acetic acid centrifuge cleanup supernatant on ODS column elute from HPLC column with methanol/water HPLC/ED 1 Pg/L 97-100 Okayama et al. 1988... 

For the 0-ethyldithiocarbonate-ended heterotelechelic PEG, the methane sulfonate end group was reacted with potassium 0-ethyldithiocarbonate. Figure 4 shows both the NMR spectra of the acetal-PEG possessing methane sulfonate (acetal-PEG-S02CH3) and the 0-ethyldithiocarbonate end groups at the co-end of the PEG chain [acetal-PEG-S(C=S)Oet]. The 0-ethyldithiocarbonate end group can be... 

No Name point. point phenyl phenyl sulfone Acetate Benzoate capto- Dnulfide thio- Miscellaneous... 

Mixed sulfonic-acetic anhydrides convert ethers to esters. Here the mixed anhydride serves as the source of the acylium ion. 

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