J. P. Rahe in Atoriiic iind N m i s c c i /~~ Morljiicarinn of MUIEI.;-(I/.% ~i~~i f l c i~i i i~i i t~i l .~ ond App1kution.r (Ed. : P. Avouris) NATO AS1 Sew. E. 1993. 239. 263-273. [5] J P Rabc. M . Siino. D. Batchelder. A. A. Kalatchev. J. :Microrc. (O\-/oiv/) 1988. /52. 573 -5x3.
Quaternisation of 1, ( k + 2)-diphosphabicyclo[k.l.0]alkanes 2, followed by treatment of the monoquaternary salts with alkyllithium or Grignard reagents produces the &isomers of 1,n-disubstituted-1,n-diphosphacycloalkanes 3 exclusively; examples containing eight-, nine-and ten-membered rings are described and the structures of two of these compounds 3a and 3f have been determined.
The aldehyde content of hydro cellulose may be readily estimated by titration with iodine in alkaline solution. Investigation of the rate of oxidation of hydrocellulose by iodine at 0° C and pH 10.6 showed that there is an initial rapid reaction in the first hour accompanied by a side reaction. This latter reaction continues after the rapid reaction has ceased and consumes iodine slowly at a constant rate. Purified cotton cellulose shows an initial reaction with iodine and after 1 hour exhibits a side reaction of the same rate as the hydrocellulose. By applying a correction for the amount of iodine consumed in the side reaction, it is possible to estimate the iodine utilized in the oxidation of aldehyde groups. Since iodine utilized in this way converts aldehyde to carboxyl groups, an, independent check on the value obtained with iodine is readily obtained by estimation of the carboxyl groups thus formed by titration with silver o-nitrophenolate. It is shown that the extent of hydrolytic degradation as determined by this method compared well with similar measurements by the viscosity method.
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Halo Michael acceptors react with catechol in aprotic solvents in the presence of potassium carbonate to form 2-substituted 1,4-benzodioxanes. Cis 0-alkyl and 0-alicyclic -halo Michael acceptors yield primarily cis 2,3-disubstituted 1,4-benzodioxanes, whereas trans 2,3-disubstituted isomers predominate when catechol is treated with trans 0-alkyl -halo Michael acceptors. It is therefore inferred that the reaction proceeds via a cis Michael addition of catechol monoanion, followed by intramolecular nucleophilic displacement of halide from the newly generated sp3 a carbon by the remaining catechol oxygen. Ethyl l,4-bromobut-2-enoate, formed by isomerization of ethyl 2-bromobut-2-enoate during the course of the reaction of the latter with catechol, is believed to be the source of the isomeric ethyl l,4-benzodioxanyl-2-acetate isolated as a minor product.
3-Ethylidino-2-oxo-1,4-benzodioxane (23). Reaction of catechol with 5b at 25°for 72 hr in the presence of KI gave 23 (18% yield): mp 74-75°(95% ethanol); nmr (CDCI3) 6.99 (s, 4, aro-
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