No abstract

Carboxyl groups can be introduced into crosslinked polystyrene by a two step process involving 2-chlorobenzoylation and cleavage of the product using a mixture of potassium tert-butoxide and water. The reaction yields can be estimated easily by the change in weight of the resin and by chlorine analysis. Carboxyl groups can also be introduced via benzoylation. The previously described method of introducing carboxyl groups, in which crosslinked polystyrene is chloromethylated and the product oxidized to a formyl resin, which is then oxidized to a carboxyl resin, can be improved by using peracetic acid in methanesulphonic acid as the oxidant in the last step. ZUSAMMENFASSUNG:Carboxylgruppen konnen in vernetztes Polystyrol uber einen ZweistufenprozeD durch 2-Chlorbenzoylierung und Aufspaltung des Reaktionsproduktes mit einer Mischung von Kalium-tert-butoxid und Wasser eingefuhrt werden. Den Umsatz kann man durch die Gewichtsanderung des Harzes und durch Chloranalyse leicht abschatzen. Carboxylgruppen konnen auch durch Benzoylierung eingefuhrt werden. Das bereits beschriebene Verfahren, um Carboxylgruppen einzufiihren, indem man vernetztes Polystyrol chlormethyliert, das erhaltene Produkt zu einem Formylharz oxidiert und dieses Produkt zu einem Carboxylharz weiteroxidiert, kann durch die Verwendung von-Peressigsaure in Methansulfonsaure als Oxidationsmittel im letzten Schritt verbessert werden.

Pentafluorophenyldiphenylphosphine (I) and its oxide (11) and sulphide (111) have been treated with sodium methoxide in methanol and with methylamine in both benzene and ethanol. All three reagents replaced only the para-fluorine substituent of the phosphine, but considerable ortho-replacement (82 and 46%. respectively, the remainder being para) in the oxide and sulphide occurred with methylamine in benzene ; methylamine in ethanol gave only para-replacement. Sodium methoxide cleaved the pentafluorophenyl group completely from the 363, Birmingham 15. oxide and partially from the sulphide.

The dilithium salts PhCR(0-Li+),. formed by the reaction of organolithium derivatives with lithium carboxylates, are stable in ether heated under reflux for 96 h when R = phenyl, 4-tolyl, or 4-or 2-methoxyphenyl, but decompose to give lithium benzoate and RLi when R = 2.6-dimethoxyphenyl, 2-thienyl, or 2-furyl. The dilithium salts react with water to give ketones ; efficient methods for the synthesis of several substituted benzophenones, 2-benzoylthiophen, and 2-benzoylfuran are reported.Base-induced cleavage of aromatic ketones is formally the reverse of the above reactions. Fluorenone, 2-chlorobenzophenone, 2.6-dimethoxybenzophenone. and 2-benzoylthiophen are cleaved readily when treated with potassium t-butoxide (1 0 equiv.) and water (3 equiv.) in ether but are unaffected by the analogous reagent prepared with lithium t-butoxide.THE reaction of phenyl-lithium with lithium benzoate gives initially the dilithium salt (3), which during work-up reacts with water to give benzophenone.1*2 Other ketones can be prepared ~i m i l a r l y . ~~ It has been suggested that the corresponding dipotassium salt (or the incipient salt) is an intermediate in the cleavage of benzophenone by a mixture of potassium t-butoxide and water in ether 7-9 or 1,2-dimetho~yethane,~JO and that the salt decomposes to phenylpotassium and potassium benzoate. This prompted us to investigate whether the dilithium salts generated in the synthesis of some aromatic ketones showed any tendency to break down to organolithium derivatives and lithium carboxylates, and we now report the results. Evidence for the breakdown of the dilithium salts has already been obtained in a few instances, but the reactions involved