Heptitol, 2,6-anhydro

Di-0-acetyl-2,6-anhydro-D-idopyranose, A-658 D-g/ycero-L-gw/o-Heptitol 2,6-Anhydro, penta-Ac, H-17 D-g/ycero-L-gw/o-Heptitol 2,6-Anhydro, pentabenzyl, H-17... 

C19H23BrO10S 4,5,7-Tri-0-acetyl-2,6-anhydro-l-0-(p-bromophenylsul- fonyl)-3-deoxy-D-gluco-heptitol BACGLO 31 369... 

On deamination, l-amino-2,6-anhydro-l-deoxy-D-giycero-D-ga-Zacfo-heptitol (84) gave the corresponding anhydroheptitol (85) in 58% yield, plus the l-deoxy-2-heptulose 86, isolated in syrupy (17%) and crystalline (8%) forms.165 The rearrangement leading to the latter... 

Substitution was also the major reaction in the deamination of l-amino-2,6-anhydro-l-deoxy-D-allitol 67and l-amino-2,6-anhydro-l,7-dideoxy-L-g(i/cero-L-ga(acfo-heptitol.168 The rearrangement product, a l,6-dideoxy-2-heptulose, was also isolated from the latter amine, the ratio of substitution to rearrangement being 1.6 1. 

With the aid of these rules, we have predicted the structures of the acetals which would be expected to result from the benzylidenation, ethylidenation and methylenation of all the tetritols, pentitols and hexi-tols. As will be seen from Table IV, the predicted structures agree very well with the accepted structures of the compounds. The rules explain, too, the syntheses of 3,5-benzylidene- and 3,5-methylene-gluco-[Pg.180]

From the oxo reaction of 3,4,6-tri-O-acetyl-D-galactal (36) (after deacetylation of the mixture of products), there was obtained, in almost quantitative yield, 2,6-anhydro-3-deoxy-D-golacto-heptitol (37) and 2,6-anhydro-3-deoxy-D-foio-heptitol (38). - Structural investigations of these anhydrodeoxyalditols paralleled those on the alditols obtained from 3,4,6-tri-O-acetyl-D-glucal. The absolute structures of compounds (37) and (38) were unequivocally established by correlation, as shown, with 2,6-anhydro-3-deoxy-D-gZuco-heptitol (27). Prior structural work" on compound (37), with the aid of periodic acid degradations only, had led to an incorrect, tentative assignment of structure. 

Attempts to use 4,5,7-tri-0-acetyl-2,6-anhydro-l,3-dideoxy-l-iodo-D-giuco-heptitol for x-ray analysis were unsuccessful, because only twinned crystals could be prepared. Use of die deacetylated p-toluenesulfonate, namely, 2,6-anhydro-3-deoxy-l-0-p-tolylsulfonyl-D-gl co-heptitol, and of the parent alditol, 2,6-anhydro-3-deoxy-D-glaco-hepti-tol, was unsuccessful because no atom of sufficient electron density was present. 

Application of the oxo reaction to tetra-0-acetyl-l-deoxy-D-arob no-hex-l-enopyranose (49) (2-acetoxy-tri-O-acetyl-D-glucal ) produced mainly one product which, on deacetylation with sodium methoxide, readily afforded 2,6-anhydro-D-g/ycefo-D-gttZo-heptitol (50) in 70% yield. This compound had previously been described by Coxon and Fletcher, and their structural proof was used in the assignment of structure to compound (50). 

From the oxo reaction of tetra-O-acetyl-l-deoxy-D-Zt/xo-hex-l-eno-pyranose (51), with dicobalt octacarbonyl as the catalyst, followed by deacetylation of the mixture of products, the expected heptitol, namely, 2,6-anhydro-D-gZt/cero-L-manno-heptitol (52), was produced in much lower yield (about 20 %). 

The conversion of tetra-0-acetyl-l-deoxy-D-arabtno(and o-lyxo)-hex-l-enopyranose into 2,6-anhydro-D-gIj/cero-D-guIo(and L-manno)-heptitol, respectively, provides chemical proof that the oxo reaction proceeds by way of cis addition of hydroxymethyl and hydrogen to the carbon—carbon double bond. 

Application of the oxo reaction at 100—110° for 20 minutes to tri-O-acetyl-l,2-anhydro-D-glucopyranose (Brigl s anhydride) (73), followed by acetylation, gave, in over 80% yield, 1,3,4,5,7-penta-O-acetyl-2,6-anhydro-D-gli/cero-D-gttlo-heptitol (74), identical with an authentic sample. Reduction of the minor component [presumed to be the aldehydo precursor of (74)] with sodium borohydride, followed by acetylation, afforded the acetylated heptitol (74). 

An isolated example of the use of x-ray diflraction analysis is provided by the work of Camerman and coworkers. Hydroformyl-ation of 3,4,6-tri-O-acetyl-D-glucal gave 4,5,7-tri-0-acetyl-2,6-anhydro-3-deoxy-D-gIuco- and -D-manno-heptitols, which were converted into the corresponding 1-p-bromobenzenesulfonates. One of these sulfonates was shown hy x-ray analysis to have the CJ(d) conformation in which all of the substituents are oriented equatorially hence, this sulfonate was the D-gluco isomer. 

Tetra-0-acetyl-2,6-anhydro-1-deoxy-D-g(/ycero-D-g(u/o-heptitol... 

Hydroformylation in benzene solution with hydrogen and carbon monoxide in the presence of dicobalt octacarbonyl303 afforded, after deacetylation, 2,6-anhydro-D-g/ycero-D-gu/o-heptitol, with two unidentified, minor products.55 Likewise, 2-acetoxy-tri-O-acetyl-D-galactal afforded mainly 2,6-anhydro-D-g/i/cero-L-mcnno-heptitoI on similar treatment. Methoxymercuration of the D-glucal derivative gave a crystalline glycoside adduct, obtained in 18% yield, which, on... 

Spontaneous reactions of the irreversible 8-D-galactosidase inhibitor 2,6-anhydro-l-deoxy-l-diazo-D-j-Zycero-L-ma/ino-heptitol have been investigated. ... 

Ester and sulphonium salt formation in the active-site labelling of jS-D-galacto-sidase from E. coli by 2,6-anhydro-l-deoxy-l-diazo-D- /ycera-L-manno-heptitol has been examined.2,6-Anhydro-l-deoxy-l-diazo-D- /yccro-L-wflnno-heptitol... 

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