1530
ERNESTL.
[CONTRIBUTION FROM
THE
JACKSON AND
NATIONAL INSTITUTE
OF
C. S. HUDSON
VOl. 61
s.P U B L I C HEALTH SERVICE]
HEALTH,u.
The Periodic Acid Oxidation of ap-Trehalose’ BY
ERNESTL. JACKSON
The two glucose components of the molecule of naturally occurring trehalose ( [ c u ] ~ ~fD 197’ in water) are now generally recognized from methyla7 0 - 1
HC---
HCOH?Q 1
1 %
HOCH:
HAOH
7 1 3
0
c. s. HUDSON
Trehalose (I) should be oxidized by periodic acid in the same manner as the methyl-o-aldohexopyranosides4to produce the tetraaldehyde (11). 7
HC 1
1
AND
‘
0
11
0
HL
0
0 1
1
H
I
Sr
--o-c=o
j
C
I 1
A
HC--‘
I
I
0
HCOH
j
I
~
HC---------’
’
1
-’
HCOH
I
CHI--’
CHsOH (IV)
(111) Di-strontium D‘,D‘-oxy-bis(D-hydroxymethyldiglycolate) r
HC -
I
CHlOH
HC-i
--A
0
I
CHzOH
I
CHiOH (11) D’,D‘-Oxy-his-(D-hydroxymethyldiglycolic aldehyde)5
a,a-Trehalose
.-o-c=o
I
O=C-H
I CHgOH
CH2OH
(1)
Sr L-o-C=O
-7
0-C-H
O=C-H
O=C-H
CH20H
H C ’
7
HC---
HCOH
i
-7
, ~
C H n l
CH2---1
(1’)
(VI)
Oxidation of a,a-trehalose with periodic acid tion results to have the pyranoside structure2 and from rotatory considerations the alpha, alpha in aqueous solution has yielded a sirupy product, configuration3 for carbon atoms 1 and 1’. a,a- presumably the tetraaldehyde (11), which upon (1) Publication authorized by the Surgeon General, U. S. Public oxidation with bromine water kept neutral with Health Service. (2) Schlubach and Maurer, Be?,, S8, 1178 (1925); cf, Bredereck, ibid., 83,959 (1930). (3) Hudson, THISJ O U R N A L , 38, 1566 (1916).
(4) Jackson and Hudson, ibid., 59, 994 (1937). ($5) The tetraaldehyde is named according t o the plan previously adopted.‘
June, 1939
PERIODIC ACID OXIDATIONOF a,a-TREHALOSE
1531
strontium carbonate has produced in a yield of Experimental 55% a crystalline strontium salt (Cl~HloOl&3r~). Oxidation of @,m-Trehalose with Periodic Acid.-To The organic acid corresponding to the strontium 25 ml. of 0.532 A4 aqueous periodic acid solution (4.2 salt yields, by hydrolysis and subsequent oxida- molecular equivalents) was added an aqueous solution of tion with bromine water, oxalic and D-glyceric 1 l R i 8 g. of pure a,a-trehalose dihydrate. The solution, made up to 50 ml. with water and kept in a 21" room, acids, the latter isolated as calcium D-glycerate in showed the rotatory changes recorded in Table I The a Myo yield. This limits the structure of the final [ h f ] D value of the reaction solution corresponds to a strontium salt to (III), (Ti') or (V). Structures specific rotation of + 160.0' for D',D'-oxy-bis-(D-hydroxy(IV) and (V), which require the septanoside (1,6) methyldiglycolic aldehyde). After twenty-four hours an ring for one glucose component of the a,a-treha- analysis of 5 nil. of the solution showed a n excess of 0.18 molecular equivalent of periodic acid; the consumption lose molecule in the case of (1V) and for both glu- of the oxidant was thus 4.02 molecular equivalents. cose components in the case of (V), are excluded The procedure for the isolation of D',D'-oxy-his-(D-hyby the known reactions of periodic acid.*j6 If droxymethyldiglycolic aldehyde) was the same as that the two glucose components have the septanoside described in a previous paper4 for the methoxydiglycolic ring structure the disaccharide, upon oxidation aldehydes from the methyl-pentopyranosides with the exception that, due to the low solubility of the tetraaldeby periodic acid or sodium metaperiodate, would hyde from a,e-trehalose in cold absolute ethanol, the solbe expected to consume six moles of the oxidant vent for extraction of the aldehyde from strontium salts and to produce four moles of formic acid. The di- in the present case was absolute methanol. To the saccharide having the septanoside structure for solution of the sirupy tetraaldehyde, obtained from 4.8 g. one of the glucose units and the pyranoside struc- of u,m-trehalose dihydrate, in 1000 ml. of water were ture for the other should consume five moles of the added i 5 g. of strontium carbonate and 6 ml. of bromine. The mixture was shaken until the bromine had dissolved oxidant and produce three moles of formic acid. and then kept in the dark at room temperature for about If both glucose units were of the pyranoside struc- seventeen hours with frequent shaking during the first ture (I) the consumption of the oxidant should be hour. After removal of excess bromine by aeration, the four moles and the production of formic acid two strontium carbonate was filtered off and washed thoroughly with hot water, The solution, freed from bromine moles. a,a-Trehalose actually consumes four ions with silver carbonate and from excess silver with moles of the oxidant when oxidized by either pe- hydrogen sulfide, was concentrated in vucuo to about 100 riodic acid or sodium metaperiodate; the acidity ml. and filtered. Di-strontium D',D'-Oxy-bis-(D-hydrOxyproduced in the reaction with sodium metaperio- methyldiglycolate) hexahydrate crystallized slowly as date corresponds to the formation of two moles of needles upon spontaneous evaporation of the aqueous formic acid. These results are thus in agreement solution; yield, 4.2 g. or 54%. Recrystallized thrice from water and dried to constant weight at 100" i n vucuo, with the pyranoside structure for each of the glu- the pure anhydrous salt showed a specific rotation' of cose components of the a,a-trehalose molecule. -24.0Oin water (c, 0.29; 1 , 4 ) ; the rotation was -52.8" in The septanoside structure is also excluded by the water a t a concentration of 0.91 g. per 100 ml. of solution presence of the D-glyceric acid moiety in the mole- (1, 2). Anal. Calcd. 'for CloHio0&r26H?O: H20, 17.10. cule of the strontium salt (111) derived from a,aFound (dried a t 100" in vucuo): HaO, 16.96, 16.81. trehalose. A disaccharide having the septanoside Calcd. for CiOH10013Sr4: C, 23.38; H, 1.96; Sr, 34.14 structure for both glucose units would be expected Found: C, 23.26, 23,21; H, 2.12, 2.04; Sr, 33.94, 33.93. to yield the strontium salt (VI) which has the The specific rotation of D',D'-oxy-bis-(D-hydroxymethylglycolic acid moiety in its molecule. If one glu- diglycolic acid) in water, obtained by liberating it from cose unit possesses the septanoside structure and the pure anhydrous strontium salt with an equivalent of the other the pyranoside structure, the yield of hydrochloric acid, was +71.3" ( 6 , 1.3; I , 2). Proof of Structure.-D',D'-Oxy-bis-(D-hydroxymethylcalcium D-glycerate from the strontium salt could diglycolic acid), prepared from 7.6 g. of the crystalline not attain the 65% actually isolated. This proof hydrated strontium salt as described for L'-methoxydiof the pyranoside structure for the two glucose glycolic acid,4 was hydrolyzed by heating its solution in components of the a,a-trehalose molecule fur- 100 ml. of water on the steam-bath for nine hours during nishes another instance of the applicability of these which the rotation decreased t o a small positive value. oxidation reactions to structural studies among The hydrolyzed acid in aqueous solution was oxidized by bromine and from the products were prepared as previously the carbohydrates. described4 barium oxalate (2.5 9.) and calcium D-glycerate. i f i J Malaprade, Bull. soc. c h i m . , 151 1, 833 (1934); [.;I 4, 90F (1937); HCrissey, Fleury a n d Jolg, J . p h a r m . chiiiz.. [SI 20, 149 (1934); I'leury and Bon-Bernatets, ibid., 181 23, 85 (1936); Clutterhuck and Retiter, J . Chnn. Soc.. 1467 (19%).
Oxalic acid from the barium oxalate was characterized b y ( 7 ) Except where otherwise stated, all rotations in this article are specific rotations a t 20' for sodium light.
ERNESTL. JACKSON AND C. S. HUDSON
1532 TABLE I ROTATORYCHANGESDURING
THE
OXIDATIONOF a,a-
TREHALOSE TO THE TETRAALDEHYDE 1.1978 g. of a,a-trehalose dihydrate in 50 ml. of 0.266 M aqueous periodic acid solution.& Time, min.
0
[MID
X 10-2
1.0254 g. of a p t r e h a l o s e dihydrate in 50 ml. of 0.2277 M aqueous sodium metaperiodate solutiona Time, min.
[MID X 10-2
$674. 4b 0 4-674, 4b 4.5 f601.2 5.1 +537.0 10.0 +504.4 6.7 $575.3 16.0 f480.5 10.5 +538.9 25.2 f458.1 15.6 +509.7 25.7 +483,7 42.2 f436.7 78 f424.0 41.6 +472,8 125 $423.0 87 +461.9 182 f455.0 200 $429.4 350 f448.2 335 +437.4 24 hrs. +444.9 24 hrs. 4-446.3 ' The solution was prepared a t 20-21 and kept thereafter in a 20-21" room. Calcd. from the specific rotation f197.1' in water for anhydrous a,a-trehalose.
Vol. 61
5 ml. of the solution showed an excess of 0.13 molecular equivalent of sodium metaperiodate, the consumption of the oxidant thus being 4.07 molecular equivalents. The acidity of the reaction solution a t the end of twentyseven hours corresponded to the production of 1.99 molecular equivalents of formic acids (10 ml., diluted with 300 ml. of water and neutralized to methyl red, required 10.77 ml. of 0.1 Nsodium hydroxide; calcd. 10.84 ml.).
Summary Oxidation of ala-trehalose with periodic acid in aqueous solution, and subsequent oxidation of the product with bromine water kept neutral with strontium carbonate, produces in a yield of 55% the crystalline strontium salt, di-strontium D',D'-oxy-bis-(D-hydroxymethyldiglycolate). The structure of the strontium salt, particularly the presence of two D-glyceric acid moieties in its molecule, proves each of the two glucose components of the a,a-trehalose molecule to possess the pyranoside structure.
usual methods. The yield of calcium D-glycerate rotating +14.6" in water was 2.26 g. or 65%. After recrystallizaD. C. RECEIVEDMARCH23, 1939 tion from water it melted a t 141-142" (uncorr.) alone or WASHINGTON, mixed with authentic calcium D-glycerate and rotated (8) T h e formic acid can be determined accurately a s shown by $14.9" in water ( c , 0.7; I , 2). Malapraden for the formic acid produced in t h e oxidation of certain Anal. Calcd. for C~HloO&a.2H20: Ca, 14.00. polyhydroxy alcohols by sodium metaperiodate. I n a n oxidation of a-methyl-D-glucopyranoside with sodium metaperiodate we have Found: Ca, 13.98, 13.95. found t h e theoretical values both for t h e consumption of t h e oxid a n t and for t h e production of formic acid which was measured a s Oxidation of a,a-Trehalose with Sodium Metaperiodate.-An aqueous solution of 1.0254 g. of pure a,a- the increase in t h e acidity of t h e reaction solution. A solution of 1.1238 g. of pure a-methyl-D-glucopyranoside in water was mixed trehalose dihydrate was mixed with 25 ml. of 0.4555 M with 25 ml. of 0.4875 M aqueous sodium metaperiodate solution a t aqueous sodium metaperiodate solution (4.2 molecular 20'. After being diluted with water t o 50 ml. and kept in a 20' equivalents). The solution, diluted with water to 50 ml. room for twenty-four hours, the solution showed [MID X 10-2 and kept in a 20" room, showed the rotatory changes +196.1", which corresponds t o a specific rotation of +121.0° for D'methoxy-D-hydroxymethyldiglycolic aldehyde. T h e specific rotarecorded in Table I. The specific rotation of D',D'-OXY- tion obtained with periodic acid4 a s t h e oxidant was +121.l0. T h e bis-(D-hydroxymethyldiglycolic aldehyde), calculated from result of a n analysis of 5 ml. of the solution for excess sodium metaperiodate showed the consumption of 2.00 molecular equivalents of the final [MIDvalue of the oxidation solution, is $160.5' t h e oxidant. T h e acidity of t h e reaction solution indicated t h e pro which is in excellent agreement with the value of +160.0" duction of 1.00 molecular equivalent of formic acid (5 ml., diluted calculated from the final rotation of the periodic acid oxida- with 300 ml. of water and neutralized t o methyl red, required 5.80 ml. tion solution. After twenty-seven hours an analysis of of 0.1 N sodium hydroxide; calcd. 6.79 ml ) ,
-
