Acetic butylthio

Methoxyethoxymethyl, 365 Enamino Derivatives, 365 4-Methyl-1,3-dioxolanyl Enol Acetate, 365 Pyrrolidinyl Enamine, 365 Benzyl Enol Ether, 366 Butylthio Enol Ether, 366 Protection of Tetronic Acids, 366 Trimethylsilyl Enol Ether, 367... 

The proline derived diamines 2 and 4 (vide supra) are also suitable chiral additives in enantiose-lective additions of a-unsubstituted enolates. Best results are obtained with the naphthyl derivative, as demonstrated in the tin(II) triflate mediated addition of the O-silylketene thio-acetal l-toT-butylthio-l-trimethylsilyloxyethane to aldehydes which delivers 3-hydroxythio esters in optical purities of up to 95% ee and chemical yields between 50 and 90 %24... 

With a- and (3-benzyloxyaldehydes, the /-butylthio ketene acetals also gave chelation-controlled addition.91... 

Treatment of 2-(rm-butylthio)-116-benzyl-3,4-diphenyl-2,6,7,116-tetrahydro[l,3]thiazino[2,3-a]isoquinoline with trityl tetrafluoroborate in acetic anhydride at 0°C gave 116-benzyl-3,4-diphenyl-6,7-dihydro-... 

R)-( - )-3-Benzyloxy-2-methylpropionaldehyde (2), obtained from N-methyl-ephedrine, reacts with the ketene f-butylthio trialkylsilyl acetal 3 in CH2C12 in the presence of TiCl4 to give 4 in >99% de. Use of BF3 etherate as the Lewis acid catalyst results in three stereoisomers.13... 

To a solution of 10 g impure 2,5-dimethoxy-(t-butylthio)benzaldehyde in 75 mL of nitromethane there was added 1.0 g of anhydrous ammonium acetate, and the mixture was heated on the steam bath 1.5 h. Removal of the excess solvent/ reagent under vacuum produced an orange oil that was (not surprisingly) complex by TLC and which would not crystallize. A hot hexane solution of this oil was allowed to slowly cool and stand at room temperature for several days, yielding a mixture of yellow crystals and a brown viscous syrup. The solids were separated and recrystallized from 40 mL MeOH to give 3.7 g 2,5-dimethoxy-4-(t)-butylthio-B-nitrostyrenc as fine lemon-yellow crystals, with a mp of93-94 °C. A second crop... 

CONJUGATE ADDITION (3-Bromopropion-aldehyde ethylene acetal. 1-r-Butylthio-1 -trimethylsilyloxyethylene. Cryptates. l-EthylsuIfinyl-3-pentanone. HexamethyF phosphoric triamide. Ketene bis-(methylthio)ketal monoxide. Organo-lithiuni compounds. Palladium(II) chloride. Phase-transfer catalysts. 

Captodative alkenes 67 can be dialkylated, for example, by addition of iso-butyronitrile radical derived from thermal decomposition of AIBN under the same conditions as those which lead to polymerization of other acrylic alkenes. For example, a-morpholino-acrylonitrile (67, c = CN, d = N(CH2CH2)20) leads to 69, in 71% yield (Scheme 12) [4a]. With a-/-butylthio-acrylonitrile (67, c = CN, d = SC(CHj)3), the same process leads to 70 in 88% yield [7]. The adduct radical 68 is highly stabilized, and is in equilibrium with dimer 70. The reaction is quite general, and has been applied to other captodative alkenes (c = CN, COR, CO2R and d = NR2, OR, SR) together with various sorts of radical partners, derived from alkanes, alcohols, thiols, thioethers, amines, amides, ketones, aldehydes, acetals and thioacetals [44, 45]. 

Butylthio)acetic acid 297 Crude 1-butanethiol (360 g) is added to a solution of sodium hydroxide (120 g) in water (600 ml), and this solution is stirred and cooled while being treated with chloroacetic acid (285 g), previously neutralized with sodium carbonate. After some hours the solution is heated and then distilled in steam to remove impurities. The residue is acidified with dilute sulfuric acid, and the (butylthio)acetic acid, which separates as an oil, is fractionated in a vacuum it has b.p. 140-144°/10-15 mm, the yield being 245 g. 

To a solution of 8.0 g of the crude 2,5-dimethoxy-4-(s-butylthio)benzaldehyde in 40 g of nitromethane there was added 0.38 g of anhydrous ammonium acetate, and the mixture was heated on the steam bath for 1 h. The reddish colored solution was decanted from some insoluble tan material and the excess nitromethane removed under vacuum. The heavy red oil that remained was diluted with an equal volume of boiling MeOH, and allowed to return to room temperature. The orange-colored crystals that slowly formed were removed by filtration and. 

The (n)-butyl compound, named 2C-T-19, has been taken to the nitrostyrene stage. Reaction between 2,5-dimethoxythiophenol and (n)-butylbromide with KOH gave 2,5-dimethoxyphenyl (n)-butyl sulfide as a colorless oil. This, with phosphorus oxychloride and N-methylformanilide, provided 2,5-dimethoxy-4-(n-butylthio)benzaldehyde as pale orange solids from MeOH, with a melting point of 78-79 °C. This, with nitromethane and ammonium acetate, gave 2,5-dimethoxy-4-(n-butylthio)-beta-nitrostyrene, with a melting point of 133-134 °C from either IPA or acetonitrile. 

Related Reagents. For comparison and more details, see also those entries that deal with other silyl ketene acetals, in particular 1-f-butylthio-l-f-butyldimethylsilyloxypropene, ketene t-butyldimethylsilyl methyl acetal, and analogs. 

A soln. of (n-butylthio)acetic acid irradiated 2.67 hrs. with Pyrex-filtered light of a 100 w. medium-pressure Hg-lamp in benzene containing benzophenone as sensitizer and thiophenol -> n-butyl methyl sulfide. Y ca. 100% based on startg. m. consumed. F. e. and sensitizers s. R. S. Davidson and P. R. Steiner, Soc. (C) 1971, 1682, 3480 without sensitizer cf. R. S. Goudie and P. N. Preston, Soc. (C) 1971, 3081. 

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