Propanediols and derivs

Dinitroxy(propaneamine). See under Amino-propanediols and Derivatives in Vol 1 of Encycl, p A251-L... 

Propanediol and its derivatives yield 5,6-dihydro-l,3-4/f-oxa-zines (36) by reaction with nitriles in the presence of sulfuric... 

Glycerol-a-monomine. See l-Amirio-2,3-propanediol and its nitrated derivatives in Vol 1, p A251-L Sc R... 

Trim ethyleneglycol and Derivatives is described as Dimethylolmethane or Propanediol in Vol 5, p D1355-L ... 

Dimethy lol methane, Propanediol, Trimethyl eneglycol or Bis(hydroxymethyl) methane and Derivatives... 

Di(methylol)-propane Di(methylol dimethyl-methane Dimethyl-propanediol Bis(hydroxy-methyl)-propane or Pentaglycol (PGc) and Derivatives... 

Aminomethylpropanediols and derivs 1 A232 2-amino-2-methyl-2,3-propanediol dinitrate 1 A232... 

Prochiral Compounds. The enantiodifferentiation of prochi-ral compounds by lipase-catalyzed hydrolysis and transesterification reactions is fairly common, with prochiral 1,3-diols most frequently employed as substrates. Recent reports of asymmetric hydrolysis include diesters of 2-substituted 1,3-propanediols and 2-0-protected glycerol derivatives. The asymmetric transesterification of prochiral diols such as 2-0-benzylglycerol and various other 2-substituted 1,3-propanediol derivatives is also fairly common, most frequently with Vinyl Acetate as an irreversible acyl transfer agent. 

The cyclization in Step B is an improvement of Butler s procedure for the synthesis of which employs less convenient reagents, KNH and l-bromo-3-chloroacetone acetal. Beside the acetals derived from neopentyl glycol, those derived from ethanol, 1,3-propanediol and 2,4-pentanediol have been synthesized by the present method. The second part of Step B involves the formation and the electrophilic trapping of cyclopropenyl anion 2, which is the key element of the present preparations. Step B provides a simple route to substituted cyclopropenones, but the reaction is limited to alkylation with alkyl halides. The use of lithiated and zincated cyclopropenone acetal, on the other hand, is more general and permits the reaction with a variety of electrophiles alkyl, aryl and vinyl halides, Me3SiCl, Bu3SnCl, aldehydes, ketones, and epoxides. Repetition of the lithiation/alkylation sequence provides disubstituted cyclopropenone acetals. 

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