SECTIONAL TRANSACTIONS.—B. 295 
Dr. T. REICHSTEIN.—Investigations in the field of ascorbic acid and 
related substances. 
The first effort of Reichstein, Griissner and Oppenauer in the field of 
ascorbic acid is not the only example of synthetic studies which, though 
based on incorrect suppositions, have turned out successfully. At the time 
when we began our work the incorrect furoid formula of Micheel and Kraft 
had just appeared. Being myself a furan specialist, this formula stimulated 
my curiosity, and work was commenced on the following lines : 
(1) Attempts were made to find models containing an endiol group, and 
the probable influence of ring structure was studied. 
(2) Efforts were made to synthesise substances analogous to ascorbic acid 
(3-keto-sugar acids) and also ascorbic acid itself. 
Two methods were developed: (a) I attempted a rearrangement of 
2-keto-acids (osonic acids), while (b) my collaborator, R. Oppenauer, 
proposed the treatment of osones with hydrocyanic acid. Positive results 
were first obtained from the latter. The former was the more difficult, 
since the appropriate 2-keto-acid was not available, and the necessary 
conditions to induce it to enolise were not quite those expected. 
(i) Osone-HC'N Method.—This was developed independently in Birming- 
ham and Ziirich with successful results. 
(ii) Transformation of 2-keto-acid—The results of H. Ohle and of Maurer 
and Schiedt on the enolisation of 2-keto-d-gluconic acid appeared while we 
were engaged on the preparation of 2-keto-/-gulonic acid (/-gulosonic acid), 
the correct formula of ascorbic acid having meanwhile been established by the 
Birmingham investigators. Details of these results are given. 
(3) Reductic acid will be described as a simple analogue of ascorbic acid, 
and the y-lactone formula will be discussed. 
(4) Attempts have been made to correlate configuration and antiscorbutic 
properties. 
Prof. W. N. Hawortn, F.R.S.—Synthesis of ascorbic acid and its 
analogues. 
The experimental methods which have been applied at Birmingham for 
the synthesis of d- and /-ascorbic acid may be summarised as follows : 
(1) Addition of hydrogen cyanide (reagents potassium cyanide and calcium 
chloride) to /-xylosone. Yield, 70 per cent. (The method of direct addi- 
tion of liquid hydrogen cyanide was published independently and almost 
simultaneously by Dr. Reichstein.) 
(2) Oxidation of gulosone direct to 2-keto-gulonic acid, followed by 
isomerisation by the method of Ohle (Z. Angew. Chem., 1933, 46, 399) 
and of Maurer (Ber., 1933, 66, 1054). 
(3) Direct oxidation of sorbose to 2-keto-gulonic acid followed by iso- 
merisation. 
In addition, the same methods have led to the synthesis of seven isomers 
or analogues of the natural vitamin. The fact that arabinosone by the 
potassium cyanide method gave the same product as that of Ohle and Maurer 
(isomerisation of a 2-keto-gluconic acid) showed that either a 2- or a 3-keto- 
hexonic acid could isomerise to the same ascorbic acid type. 
The synthetic /-ascorbic acid (I) has the same physiological activity as 
the natural product (Haworth, Hirst and Zilva). Of the isomers and 
analogues obtained so far only the d-arabo-ascorbic acid (II) shows activity 
which is in the least comparable. 
