2 ‐ Desoxy ‐ d‐ xylose aus d‐Glucose über 3‐Desoxy‐d‐galaktose

Weygand, Friedrich; Wolz, Hans

doi:10.1002/cber.19520850314

Cited by 46 publications

(5 citation statements)

References 9 publications

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“…spectrum showed an absorbance at 1740 cm-' indicating the presence of an ester carbonyl. The presence of the double bond, although not clearly discernible in the i.r., was confirmed by reduction over palladium to 3-0-acetyl-1,2 ;5,6-di-0-isopropylidene-a-D-gulofuranose (9). Reduction of 7 with deuterium gave a scrambling pattern identical to that obtained from reduction of 5 with deuterium.…”

Section: -Isopropylidene-d-hexofur-mentioning

confidence: 60%

“…The trans Hz-H, compounds 1,2;5,6-di-0-isopropylidene-D-glucofuranose and -L-idofuranose derivatives have small couplings of less than 0.5 Hz (6). With Hz and Hg cis in 7, the acetate group (7.9 z) must be cis to the oxygen at C-2, the expected arrangement since catalytic reduction gives only the D-gulo compound (9). The C-3 hydrogen is at 4.35 z occurring as a tripleted doublet being coupled to the two C-6 hydrogens at 5.5 z.…”

Section: -Isopropylidene-d-hexofur-mentioning

confidence: 97%

“…cis-Reduction must occur trans to the 1,2-0-isopropylidene group and results in the known D-gulo product (9). In the hope that n.m.r.…”

Section: -Isopropylidene-d-hexofur-mentioning

confidence: 99%

“…indicated that this compound was 3-deoxy-1,2 ;5,6-di-0-isopropylidene-a-D-xylohexofuranose (11). The product was purified and was found identical by n.m.r., i.r., mass spectroscopy, melting point, and optical rotation to 11 prepared by the reduction of 1,2;5,6-di-0-isopropylidenea-D-erytlvohex-3-enose (9).…”

Section: -Isopropylidene-d-hexofur-mentioning

confidence: 99%

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Unsaturated derivatives of the 1,2;5,6-di-O-isopropylidene-D-hexofuran-3-uloses

Slessor¹,

Tracey²

1970

Can. J. Chem.

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The formation of the two 3-0-acetyl-1,2;5,6-di-O-isopropylidene-~-hex-3-enoses from the four 1,2;5,6-di-0-isopropylidene-D-hexofuran-3-uloses is reported. Treatment of the two en01 acetates with hydrogen or deuterium in the presence of palladium or platinum leads to rearrangement as well as reduction and reductive hydrogenolysis of the acetoxy group. This rearrangement makes the en01 acetates unsuitable as intermediates in the stereospecific synthesis of deuterated sugars of high isotopic purity.Canadian Journal of Chemistry, 48,2900 (1970) During our investigation of the reactions and syntheses of the 1,2;5,6-di-0-isopropylidene-Dhexofuranoses (1) it was observed that reduction of the enol acetate of 1,256-di-0-isopropylidenea-D-ribohexofuranos-3-ulose prepared by the method of Meyer zu Reckendorf (2) did not proceed through a simple cis addition of hydrogen. In an attempt to clarify the mechanism by which the reduction proceeds, we have studied the reduction of the en01 acetates derived from diacetone 3-keto-D-ribohexose and 3-keto-Dlyxohexose under a variety of conditions.In the formation of the two en01 acetates from their parent ketones a marked difference in the rate of formation of the final products was observed. Treatment of the four ketones; 1,2;5,6-di-0-isopropylidene-a-D-ribohexofuranos-3-ulose (I), 1,2 ;5,6-di-0-isopropylidene-a-D-xylohexofuranos-3-ulose (2), 1,2;5,6-di-0-isopropylidene-P-D-lyxohexofuranos-3-ulose (3), and 1,2;5,6-di-0-isopropylidene-P-D-arabinohexofuranos-3 -ulose (4) as 1 % solutions of the sugar in 30% acetic anhydride in pyridine at 36" yielded the enolic sugars (5 and 6) (see Scheme 1). A qualitative comparison of reaction rates was provided by following the reactions by thin layer chromatography (t.1.c.) until complete. The results are given in Table 1.An attempt to form 5 by treating the 3-ketodiacetone-D-ribohexose with isopropenyl acetate resulted in the formation of 1,2-0-isopropylidene-3,5-di-0-acetyl-WD-ribohexofuranos-3-use (13) in good yield. The identity of this compound was deduced from nuclear magnetic resonance (n.m.r.), infrared (i.r.), ultraviolet (u.v.), and mass spectroscopy. The n.m.r. spectroscopy indicated the presence of two isopropylidene methyls (8.43 and 8.59 T), two acetate methyls (7.79 z ) , and six non-equivalent protons which were assigned as ?This time may be longer than given. After this length of time breakdown products begin appearing on the 1.l.c. plates.shown in Table 2. The presence of acetate was also confirmed by the presence of an i.r. absorbance at 1750cm-'. The absence of an OH absorbance above 3000 cm-' in the i.r. and the absence of any carbonyl absorption in the 260-340 mp region ruled out the presence of a free or hydrated ketone in 13. The mass spectrum gave a large (M-15)+ peak at m/e 287. Identification of this compound was confirmed by acetylating the known 1,2-0-isopropylidene-a-Dribohexofuranos-3-ulose prepared from 1,2 ;5,6-di-0-isopropylidene-a-D-ribohexofuranos-3-ulose by the method of Theander (3).Reduction of 5 in etha...

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Section: -Isopropylidene-d-hexofur-mentioning

confidence: 60%

Section: -Isopropylidene-d-hexofur-mentioning

confidence: 97%

“…cis-Reduction must occur trans to the 1,2-0-isopropylidene group and results in the known D-gulo product (9). In the hope that n.m.r.…”

Section: -Isopropylidene-d-hexofur-mentioning

confidence: 99%

Section: -Isopropylidene-d-hexofur-mentioning

confidence: 99%

See 2 more Smart Citations

Unsaturated derivatives of the 1,2;5,6-di-O-isopropylidene-D-hexofuran-3-uloses

Slessor¹,

Tracey²

1970

Can. J. Chem.

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“…Aldehyde mesylate 3, scheme, which is readily obtained by standard pro cedures from 2, undergoes /3-elimination quantita tively in refluxing pyridine to give 4. The potential of 4 as chiral synthon is enhanced by the fact that catalytic hydrogenation of similar systems such as 3-deoxy-l,2:5,6-di-0-isopropylidene-a-D-glucose-3-ene occurs stereoselectively at the less hindered face, as dem onstrated by Weygand and Wolz [30]. Sun and Fraser-Reid [31] have described the prep aration of this m aterial and Nakanishi et al [32] have prepared it from l,2:5,6-di-0-isopropylidene-3-0-/?-toluensulfonyl-a-D-glucopiranose [33], by a similar route.…”

Section: Resultsmentioning

confidence: 96%