Sorbopyranose 1.2- 0-isopropylidene

Deoxy-4-fluoro-D-fructose (552) was prepared (59%) by fermentation of 3-deoxy-3-fluoro-D-mannitol with Gluconobacter oxydans. The structure of 552 (fi-T) form) was confirmed by the n.m.r. spectrum, which resembles that of 4-deoxy-4-fluoro-Q -D-sorbopyranose (553) 552 was identical with one of the products obtained from the oxirane-ring opening of 3,4-anhy-dro-l,2-0-isopropylidene- -D-tagatopyranose with KHFj. 

In the sorbose series 3-methyl-D-sorbo8e14 has been synthesized, as well as the aforementioned 4-methyl-8 derivative the latter compound was obtained in a series of reactions from D-fructose derivatives through l,2-isopropylidene-3,4-anhydro-D-psicose. In the earlier study8 the configuration of the 4-methyl ketohexose was shown to be that of a D-sorbopyranose by methylation of l,2-isopropylidene-4-methyl-D-sorbose (VI) to the trimethyl derivative (LXV) which was hydrolyzed to 3,4,5-trimethyl-D-sorbose (LXVI). The latter compound, on oxidation, gave derivatives of levorotatory dimethoxysuccinic acid (LXVIII) and xylo-trimethoxyglutaric acid (LXVII). 

Further acetalation of the trans-disposed hydroxyl groups on the pyranoid ring is not sterically favored, but, nonetheless, 1,2 3,4-di-0-isopropylidene-/S-L-sorbopyranose (15) and l,2 4,5-di-0-iso-propylidene-/3-L-sorbopyranose (23) have been isolated in small proportions. These diacetals are not intermediates in the direct formation of 3, but appear to be the products of secondary pathways. 

Ohle isolated an isomeric mono-O-isopropylidene-L-sorbose from a similar reaction. After removing diacetal 3, he acetylated the remaining mixture containing monoacetals. Fractional recrystallization of the distilled mixture of triacetates was effected from methanol-water, and, on saponification, one fraction of the crystalline material gave l,2-0-isopropylidene-o -L-sorbopyranose (11) in 3% yield from L-sorbose. Periodate oxidation of 11 showed consumption of two moles of oxidant per mole, with formation of one mole of formic acid. The monoacetal 11 was also isolated in 16% yield when a suspension of L-sorbose and copper(II) sulfate in impure acetone was shaken for seven days. Other products were 3 and an isomeric di-O-isopropylidene-L-sorbose which was obtained in 1% yield and regarded by Ohle as slightly impure. Its properties (m.p. 155-157°, [aJu -f-44.9° in acetone) closely match those of l,3 4,6-di-0-isopro-pylidene-j8-L-sorbofuranose (18) (m.p. 159-160°, [a]i)-f-43.4° in acetone), identified by Maeda in 1967. Patil and Bose later isolated, but did not identify, a diacetal which was probably 18 (m.p. 155-157°, [a]n -f-4.49° in acetone). 

Ohle and Just synthesized l,2-0-isopropylidene-4-0-methyl-j8-D-sorbopyranose (99) from l,2-0-isopropylidene-3-0-p-tolylsulfonyl-j8-D-fructopyranose (97) by successive Walden inversions involving 3,4-anhydro-l,2-0-isopropylidene-j3-D-psicopyranose (98) as the intermediate (see Scheme XV). 

Free Sugars and Simple Derivatives Thereof. — jJ-D-Arabinopyranose (n.d.), jJ-D-lyxopyranose (n.d.), 3-D-xylopyranose tetrabenzoate and 1,5-anhydro-2,3,4-tri-O-benzoylxylitol, a-D-glucopyranose (a refinement based on previously published n.d. data), 1,2-O-isopropylidene-a-D-glucofuranose, a-L-sorbopyranose (n.d.), d-deoxy-a-L-sorbofuranose," and a-D-mawno-heptulo-pyranose. ... 

O-Isopropylidene, di-Ac 3,4-Di-O-acetyl-5-deoxy-5-fluoro-l,2-0-isopropy-lidene-a-L-sorbopyranose [55908-30-0]... 

Acetamido-6-deoxy-2,3-0-isopropylidene-a-L-sorbofuranose, A-337 6-Acetamido-6-deoxy-L-sorbofuranose, A-337 4-Acetamido-3,5-di-0 -acetyl-4-deoxy-1,2-0 -isopropy lidene-a-L-sorbopyranose, A-335... 

Acetyl-l,3,4,5-tetra-0-benz yl-a-L-sorbopyranose, S-60 2-0-Acetyl-l,3,4,5-tetra-0-benz yl-p-L-sorbopyranose, S-60 l-Amino-l-deoxy-2,3 4,6-di-0-isopropylidene-a-L-sorbofuranose, A-334 6-Amino-6-deoxy-2,3-0-isopropylidene-l-0-methyl-a-L-sorbofuranose,... 

Isopropylidene-3,4,5-tri-O -mesyl-a-L-sorbopyranose, S-60 Methyl 5-acetamido-1,3-0-benzylidene-5-deoxy-a-L-sorbopyranoside,... 

P-D-Fructopyranose a-D-sorbopyranose l,2 2,l -dianhydride, F-77 P-D-Fructopyranose a-L-sorbopyranose l,2 2,l -dianhydride, F-78 Isopropyl 3,4,6-tri-O -acetyl-2-bromo-2-deoxy-p-D-glucopyranoside, B-74 Methyl 4,5-anhydro-2,3-0-isopropylidene-D-ribonate, A-691 Methyl 4,7-anhydro-5,6,8-tri-0-benzyl-2,3-dideoxy-2,2,3,3-tetradehydro-D-o/fro -octonoate, M-212 Methyl 4,7-anhydro-5,6,8-tri-0-benzyl-2,3-dideoxy-2,2,3,3-tetradehydro-D-o//o-octonoate, M-212 Methyl 3,5-anhydro-p-D-xylofuranoside, A-728 Methyl 2-bromo-2-deoxy-4,6-0-benzylidene-p-D-glucopyranoside, B-74 Methyl 2-bromo-2-deoxy-p-D-glucopyranoside, B-74 Methyl 3,4,6-tri-O-acetyl-2-bromo-2-deoxy-p-D-glucopyranoside, B-74 v-Octose l,T-Anhydro, 0-17... 

Chloro-5-deoxy-2,3-0-isopropylidene-a-L-sorbopyranose, C-102 5-Chloro-5-deoxytalose u-form, C-105... 

Deoxy-5-fluoro-1,2- O -isopropylidene-a-D-glucofuranose, D-91 5-Deoxy-5-fluoro-1,2- O -isopropylidene- p-L-idofuranose, D-97 5-Deoxy-5-fluoro-1,2- O -isopropylidene-a-L-sorbopyranose, D-108 5-Deoxy-5-fluoro-1,2- O -isopropylidene-a-D-xylofuranose, D-120 5-Deoxy-5-fluorosorbose a-L-Pyranose-/orw, D-108 5-Deoxy-5-fluoroxylose D-Furanose-/orm, D-120 5-Deoxy-5-iodoarabinose L-form Ethylene dithioacetal, 2,3,4-tri-Ac, D-251... 

The n.m.r. spectroscopic investigation of the reactions of pentonolactones with acetone and benzaldehyde in acidic media is covered in Chapter 21, as are conformational studies on 2,3-G-isopropylidene-a-L-sorbopyranose derivatives. l,2-0-Isopropylidene-a-D-t /o-pentodialdo-l,4-furanose dimers are referred to in Ch er 22, and some 7-carbon sugar lactones which were characterized as their isopropylidene-and cyclohexylidene-acetals are noted in Chtytters 2 and 16. 

Other Anhydrides.- A laboratory scale apparatus has been designed for the pyrolysis of cellulose in large quantities to give 1,6-anhydro-)9-D-glucopyranose,and the preparation of this compound uniformly labelled with C by pyrolysis of a [U- " C] glucan has been reported. Pyrolysis of plant cell wall materials has afforded 1,5-anhydro-/9-L-arabinofuranose in up to 78% yield based on the amount of L-arabinose present in the glycan. The treatment of acetylated inulin with anhydrous HF has allowed the formation of the fructofuranose 1,2 2,1 -dianhydride (27), whereas 2,3 4,6-di-Q-isopropylidene-a-L-sorbopyranose on brief treatment under the same conditions afforded the sorbofuranose 1,2 2,1 -dianhydride (28) isolated as its crystalline hexaacetate. The... 

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