HENRY'A.LARDY
518
VOl. 69
/CONTRIBUTION FROM THE DEPARTMENT OF BIOCHEMISTRY, UNIVERSITY OF WISCONSIN 1
1,Z,3,4-Tetraacetyl-cu-D-glucopyranose BY HENRYA. LARDY after one minute the precipitated triphenylbromomethane The synthesis of 1,2,3,4-tetraacetylTP-~-glucowas filtered off and washed with acetic acid (3 cc.). The pyranose from the corresponding 6-trityl com- filtrate was immediately poured into ice water and chloropound by Helferich and Klein' made available a form; the chloroform extract waswashed three times with valuable intermediate for the synthesis of several ice water, dried over. sodium sulfate and evaporated to a disaccharides, glucose-6-phosphate2 and certain light sirup. The cautious addition of dibutyl ether and scratching caused the compound to crystallize in small related compounds. The preparation is given in platelets. When filtered, washed with butyl ether and "Organic Syntheses'I3 and was further improved dried in vacuo the froduct weighed 0.90 g. (56%) and by a new procedure2 for crystallizing the product melted a t about 99 . One recrystallization from chloroform bv addition of butvl ether brought the substance to involving the use of di-n-butyl ether. m. p. 102-163" (cor.) an-d rotation: [ a I z B ~ A parallel synthesis from tetraacetyl-G-tri- constant $119 * 1" ( c = 1.5, in CHC13). phenylmethyl- ff-D-glUCOSe has now yielded 1,2,3,Anal. Calcd. for C14H20010: C, 48.3; H, 5.79. Found: 4-tetraacetyl-a-D-glucopyranose for the first time C, 48.0;H, 5.84. in pure crystalline form. Although Reynolds and Tritylation of 1,2,3,4-Tetraacety~~-~-g~ucopyranose.Evans4 successfully employed the compound for To a solution of 0.33 g. of tetraacetyl-cu-D-glucosein anhythe synthesis of a-gentiobiose octaacetate, their drous pyridine (2 cc.) 0.28 g. (1.2molar equivalents) of chloride was added and the mixture was shaken until specimen was a sirup for which no analytical or ro- trityl the trityl chloride dissolved. After standing overnight tational data were reported. at room temperature, the solution was cooled to 0" and a Butyl ether has been found to facilitate the crys- small chip of ice was added. After one hour, more chipped tallization of the hexose tetraacetates as well as of ice was added while stirring. The product which crystallized during the next half hour was filtered off, washed a number of other carbohydrate derivatives. with water and dried on a clay plate. When recrystallized The structure of the new tetraacetate was con- twice from absolute ethanol and dried over calcium chlofirmed by tritylation which gave the original tetra- ride, 0.3 g. of tetraa~etyl-6-trityl-cu-~-glucose was obacetyl-6-triphenylrnethyl-a-~-glucose,~ and by tained: m. p. 125-128 a-Gentiobiose 0ctaacetate.-A mixture of " Drierite"8 condensation with acetobromoglucose to a-gen- (7.0 g.), silver oxide' (2.09.) and 1,2,3,4-tetraacetyl-a-~tiobiose octaacetate. A molecular rotation in glucopyranose (2.7g.) in anhydrous alcohol-free chlorochloroform of 41,400' was found for 1,2,3,4-tet- form (7 cc.) was stirred for one hour in a three-necked raacetyl-a-D-glucopyranose, whereas the corre- flask fitted with a mercury-sealed stirrer, a dropping funnel and a drying tube. After the addition of 0.3g. of iodine a sponding figure for the known p-isomer is 4,200'. solution of acetobromoglucose (3.29.) in anhydrous chloThe numerical difference of 37,200 (2 A. value) is roform (10 cc.) was added dropwise during the course of in the middle of the range (33,000 to 40,000 with one hour and the stirring was continued for eighteen hours. an average of 36,000 t o 37,000) predicted by Hud- The insoluble materials were removed by filtration through a precoated funnel and washed thoroughly with chloroson's Rules of Isorotation6 for pairs of acetylated form. The chloroform was evaporated under reduced sugars differing only in the configuration of the pressure to a sirup from which a-gentiobiose octaacetate acetyl group on carbon atom 1. crystallized when absolute ethanol was added. When reThe preparation of acetylated 6-glycosido-a- crystallized twice from absolute ethanol and dried, the weighed 2.2 g. (42% of theoretical); it melted glucose compounds should be facilitated by the product a t 190-191" (cor.) and had [ a I z 4-54.3 6~ * 1" ( c = 2.1,in availability of the a-tetraacetate in crystalline CHCl,). When mixed with the a-gentiobiose octaform. acetate (m. p. 188-189.5') produced by Hudson and
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Johnson$ from the corresponding ¶, compound, by treatment with zinc chloride and acetic anhydride, the melting 1,2,3,4-TetraacetyI~-~-glucopyranose.-6-Tr~tyl-tetra-point was 188-190" (cor.). acetyl-a-D-glucopyranose obtained as a by-product in the preparation of the corresponding p-tetraacetate3 was reSummary crystallized from absolute ethanol until m. p. and rotation The use of dibutyl ether as a crystallizing agent were constant.' A quantity of 2.7 g. of this 6-trityltetraacetyl-cu-D-glucopyranose was dissolved in glacial made it possible to prepare tetraacetyl-a-D-gluacetic acid (12cc.) and to the cooled solution 32% hydro- copyranose as pure crystals, m. p. 102-103° bromic acid in glacial acetic acid (1 cc.) was added;
Experimental
(1) B. Helferirh a.nd W. Klein, A n n . , 460, 219 (1926). (2) H . A. Lardy .and H. 0. L. Fischer, J . B i d . Chcm., 164, 513
(1946). (3) "Organic Syntheses," 22, 56 (1942). (4) D. Reynolds and W. L. Evans, THISJOURNAL, 60, 2559 (1938). (5) B. Helferich, L. Moog and A. Junger, Ber., 68, 872 (1925). (6) C. S. Hudson, THIS JOURNAL, 81, 66 (1909). (7) M. p. 130-132' (cor.) with sintering at 126O, [UlZ'D +lo2 * 0.5" (c 2, in CHC13). Helferich, et at., see footnote 5, reported m. p. 129-131' [ U ] " D i97.8'.
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(cor.) and with a specific rotation in chloroform [aIz6D 119 j= 1'. The structure of the compound was confirmed by its conversion to known compounds.
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MADISON, WISCONSIN
RECEIVEDSEPTEMBER 20, 1946
(8) Preheated at 400' for three hours and held over phosphorus pentoxide. (9) C. S. Hudson and J. M. Johnson, THISJOURNAL, 89, 1272 (1917). A specimen of their compound was generously supplied by Dr. Hudson.
