IQ2 A GENERAL REVIEW OF 



rotatory powers of these esters and of the corresponding 

 tartaric esters. 



Purdie and the writer (58) have prepared a series of 

 dimethoxy-compounds similar to those derived from mono- 

 methoxysuccinic acid. It was hoped that information bearing 

 on the tautomeric behaviour of succinyl chloride might be 

 obtained by the study of its active analogue d-dimethoxy- 

 succinyl chloride. Neither this compound nor Z-methoxy- 

 succinyl chloride, however, exhibited mutarotation when 

 dissolved in indifferent solvents, and from these and other 

 experiments it must be concluded that the substances do not 

 consist of mixtures of dynamic isomerides. Treatment of 

 methyl ^-dimethoxysuccinate with magnesium methyl iodide 

 yielded the laevorotatory yS-dimethoxy-/3e-dimethylhexane- 

 e-diol, HO.CMe 2 .CH(OMe).CH(OMe).CMe 2 .OH, which, 

 as already mentioned, cannot be further methylated by the 

 silver oxide reaction. When repeatedly distilled, the sub- 

 stance loses water and becomes converted into the dextro- 

 rotatory furan derivative : 



CH(OMe) . CMe 2 \ 



'I >0. 



CH(OMe) . CMe/ 



A corresponding compound is directly obtained when mag- 

 nesium phenyl bromide is substituted for magnesium methyl 

 iodide in the above reaction ; this product is 3 : 4-dimethoxy- 

 2:2:5: 5-tetraphenyltetrahydro-furan : 



CH(OMe) . CPh 2 



1 

 CH(OMe).CPh 



THE ALKYLATION OF MONOSACCHARIDES 



Although benzoin and salicylaldehyde can be directly 

 alkylated by the silver oxide method, the process is not directly 



