Methylene chloride point group

A solution of N-(2-aminobenzvl)-1-phenyl-2-metKylaminoethanol-1 was prepared by the reaction of a-bromo-acetophenone and (2-nitrobenzyl)methylamine, followed by hydrogenation of the nitro group by means of nickei on diatomaceous earth at room temperature and reduction of the CO group by means of sodium borohydride. The intermediate thus produced was dissolved in 100 ml of methylene chloride and introduced dropwise into 125 ml of sulfuric acid at 10° to 15°C. After a short standing, the reaction mixture was poured onto ice and rendered alkaline by means of a sodium hydroxide solution. Dy extraction with ether, there was obtained 1,2,3,4-tetrahydro-2-methyl-4-phenyl-8-amino-iso-quinoline. The base is reacted with maleic acid to give the maleate melting point of the maleate 199° to 201°C (from ethanol). 

In the experimental sequence, the authors at this point replace methylene chloride by THF (tetrahydrofuran) and the mixture is exposed to a mild ba.se in a two-phase system. The three carbonyl groups of V should all be reactive towards nucleophilic bases such as hydroxide ion, but they also differ remarkably in their susceptibility. Of the three, the keto function would be expected to be more prone to react as a consequence of dipole-dipole interactions with its vicinal ester grouping. The intermediate ketone hydrate anion VI may in principle trigger the disconnection of the three bonds around the central carbon as follows ... 

C-to-O silyl-group transfer without alkene formation is relatively uncommon. However, Oshima, Utimoto, and co-workers reported that metalation of dichloromethylsilane 96 and addition to aldehydes provided fi-alkoxysilanes (e.g., 97) that imderwent 1,3-rearrangement and alkylation to 98. Notably, the addition of HMPA promoted the 1,3-Brook rearrangement, presumably by increasing the reactivity of the lithium alkoxide intermediate. As the authors pointed out, this sequence demonstrated 96 as a methylene chloride dianion equivalent. ... 

Cellulose Triacetate n A member of the cellulosic plastics family made by reacting purified cellulose with acetic anhydride in the presence of a catalyst in such a manner that at least 92% of the hydroxyl groups are replaced by acetyl groups. Because of its high softening point this material cannot be molded or extruded. Its major use is for casting films or spinning fibers from solutions, such as in a mixture of methylene chloride and methanol. 

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