New synthetic methods developed in the field of organotin compounds since 1959 are reviewed. The use of alkyl aluminum compounds brings an advance in the preparation of tetraalkyltin derivatives, alkyltin halides, and alkyltin hydrides. Organotin hydrides ofer new possibilities for the production of monomeric and polymeric organotin compounds. Diethyltin and diphenyltin, which are obtained by catalytic dehydrogenation of the respective dialkyltin dihydrides, are cyclic compounds. -The literature since 1959 is reviewed.
0.5n KOH in 2-Athoxy-athanol hinzu und kocht 3 Stdn. unter . Danach wird abgekuhlt, in einen 300-ccm-Weithalskolben unter Nachspiilen mit Wasser iibertragen und rnit 0 . 5 n HCI gegen Phenolphthalein titriert. In der gleichen Weise wird auch die Blindprobe bestimmt. Die so ermittelten Verseifungszahlen stimmen mit den theoretischen gut iiberein. Die Alkylzinnhalogenide der drei Reihen R3SnX, RzSnX2 und RSnX3 sind wichtig fur die Darstellung nahezu aller Zinnalkyle rnit funktionellen Gruppen3). Organozinnhydride, die aus den entsprechenden Zinnhalogeniden zu erhalten sind3-6), werden in steigendern Ma& in der praparativen Organozinn-Chernie verwendet 1.3.4.7).
IR-Spektren
Phosphorus pentoxide reacts with ether to form bicyclotetraphosphate ester (II), cyclotetraphosphate ester (III), isocyclotetraphosphate ester (IV), and tetraphosphate ester (V). Phosphorus n.m.r. measurements show the content of the mixtures. The so-called "ethyl metaphosphate" (Langheld ester) ! is a mixture of III (50% t~45%), IV (36% to 25%), and V (14% to 30%). The product of the reaction of ether and phosphorus pentoxide 3 has recently become interesti?g as a re~gent ,for the synthesis of polysaccharides, polypeptides, and polynucleotides. 4Unfortunately, the ,
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