Hexofuranose, 5-deoxy

The mass spectra of methyl 3-deoxy-p-v-tkreo-pentopyrano-side, methyl 4-deoxy-j3-T>-thieo-pentopyranoside, and 5-deoxy-fi-D-xylo-furanoside are discussed and compared fragmentation paths are sufficiently different to allow identification on the basis of their mass spectra. On the other hand, the mass spectra of methyl 2- and 3-deoxy-5-O-methyl-f3-i>-erythro-pentofuranosides do not exhibit fragmentation differences. The mass spectra of 3-deoxy-l,2 5,6-di-O-isopropylidene -d-xylo - hexofuranose, 5- deoxy -1,2-0-isopropylidene-D-xy o-hexofuranose, and 6-deoxy-l,2-0-iso-propylidene-D-glucofuranose show prominent differences, even between the 5- and 6-deoxy isomers. The interpretation of the spectra was aided by metastable-ion peaks, mass spectra of DzO-exchanged analogs, and the mass spectrum of an O-isopropylidene derivative prepared with acetone-d6. 

Following Bock s observation with the only substrate that had been converted quantitatively, 5-deoxy-D-xy/o-hexofuranose ( 5-deoxy-D-glucose , 59), it was discovered [83] that any derivative of D-glucose not bearing a free hydroxyl function at C-5, such as the 5-azidodeoxy (71), the 5-deoxyfluoro (73), and the 5-0-... 

The remaining derivatives, 3-deoxy-l,2 5,6-di-0-isopropylidene-D-xt/Zo-hexofuranose (34,39) (9) and 5-deoxy-l,2-0-isopropylidene-D-xt/Zo-hexofur-anose (23, 41) (11), together with the previously mentioned 10 comprise... 

Figure 8. Mass spectrum of 5-deoxy-l,2-0-isopropylidene-T>-xy o-hexofuranose...

In the mass spectrum (Figure 6) of 3-deoxy-l,2 5,6-di-0-isopropyli-dene-D-xt/Zo-hexofuranose (9) the fragmentations described above are found at m/e 229, 171, 143, 111, and 101. The fragments at m/e 143 and 101 arise by cleavage of C-4-C-5 with charge retention on C-4 and C-5, respectively (see Equations 17 and 18). Scheme 2 summarizes the losses of a methyl group, acetone from the second cyclic ketal function, and... 

In the mass spectrum (Figure 8) of the corresponding ketal of 5-deoxy-D-xt/Zo-hexose, 5-deoxy-l,2-0-isopropylidene-D- rt/Zo-hexofuranose (11), the peak from C-4-C-5 cleavage, m/e 159, is of minor relative intensity. Since the ions at m/e 159 are the same from both isomers, 10 and 11, the intensity difference must be attributable to the lower stability of the primary radical formed from C-5 of 11 compared with the secondary radical from 10 ... 

Acetyl-5-deoxy-a-D-xy/o-hex-5-ynofuranose or 6-0-acetyl-5,5,6,6-tetradehydro-5-deoxy-a-D-xy/o-hexofuranose... 

Ci7H26N207 3-(S)-Acetamido-spiro-3,4 -(R)-(3-deoxy-l,2 5,6-di-0-isopro- pylidene-a-D-rifoo-hexofuranose-3-yl)-2-pyrrolidinone SHFSAP 38 469... 

Di-0-isopropylidene-a-D-rtbo-hexofuranos-3-ulose (100) was treated with (chlorofluoromethylene)triphenylphosphorane (prepared by reaction of triphenylphosphine on difluorocarbene generated in situ by reaction of potassium ferf-butoxide with dichloro-fluoromethane), to give cis- and rans-3-C-(chlorofluoromethylene)-3-deoxy-l,2 5,6-di-0-isopropylidene-a-D-ribo- (101 and 103) and -xyfo-hexofuranoses (105 and 107), which, on treatment with lithium aluminum hydride, gave cis- and frans-3-deoxy-3-C-(fluoromethyl)-1,2 5,6-di-O-isopropylidene-a-D-rtbo- (102 and 104) and -xyZo-hexofura-... 

The addition of iodine trifluoroacetate (produced by reaction of iodine with silver trifluoroacetate) to unsaturated carbohydrates has been investigated.134 Treatment of 5,6-dideoxy-l,2-0-isopropylidene-a-D-xylo-hex-5-enofuranose (89) with silver trifluoroacetate and iodine in acetonitrile gave 3,6-anhydro-5-deoxy-5-iodo-l,2-0-iso-propylidene-a-D-gluco(and /3-L-ido)furanose (91) and 5-deoxy-5-iodo-l,2-0-isopropylidene-6-0-(trifluoroacetyl)-o -D-gluco(and/or /3-L-ido)-furanose (92), with the former preponderating. Component 91 was converted into 3,6-anhydro-5-deoxy-l,2-0-isopropylidene-a-D-xj/io-hexofuranose (94) by hydrogenation over Raney nickel (see also, Section III,3 p. 299), and component 92 was converted into 5-deoxy-l,2-0-isopropylidene-a-D-xy/o-hexofuranose (95) by treat-... 

An investigation of the reduction of chlorodeoxy sugars with lithium aluminum hydride has been reported.68 In one experiment, 3-deuterio-l,2 5,6-di-0-isopropylidene-a-D-allofuranose (197) was prepared, and converted into 3-chloro-3-deoxy-3-deuterio- l,2 5,6-di-0-isopropyl-idene-a-D-glucofuranose (198) by treatment with triphenylphos-phine-carbon tetrachloride reduction with lithium aluminum hydride gave 3-deoxy-3-deuterio-1,2 5,6-di-O-isopropylidene-a-D-r/foo-hexofuranose (199), a result which established that the reduction must have occurred with, retention of configuration at C-3. 

Anhydro-3-deoxy-l,2-0-isopropylidene-a-D-x //o-hexofuranose— 3-deoxy-D-x /io-hexose 6-phosphate.207... 

DE0XY-1,2 5,6-01-0-1SOPROPYLIDENE-a -D-ri bo-HEXOFURANOSE (a-O-rlbo-Hexofuranose, 3-deoxy-l,2 5,6-bis-0-(l- ethylethylidene)-)... 

Deoxy-l,2 5,6-di-0-i sopropy1idene-a-D-ri bo-hexofuranose has been prepared by a variety of other methods, the most widely used of which is the Raney nickel reduction of the 3-S-[(methylthio)carbonyl1-3-thioglucofurunose... 

Deoxy-l,2 5,6-di-0-isopropylidene-a-D-r1bo-hexofuranose D-ribo-Hexofuranose, 3-deoxy-l,2 5,6-di-0-isopropylidene, a- (8) a-D-ribo-Hexofuranose, 3-deoxy-l,2 5,6-bis-0-(l-methylethyliderie)- (9) (4613-62-1) l,2 5,6-Di-0-isopropylidene-a-D-glucofuranose Glucofuranose, l,2 5,6-di-0-isopropylidene, a-D- (8) a-D-glucofuranose, 1,2 5,6-bis-0-(1-methyl -ethylidene)- (9) (582-52-5)... 

Hydrogenation of 78 in ethanol in the presence of Raney nickel (W-4) for 2 days at room temperature did not produce the anticipated 5-deoxy-5-C-(phosphinyl)hexofuranose 84 but, instead, afforded,52 53 in 90% yield, a 1 1 mixture of the (5R)- and (5S)-5,6-dideoxy-5-C-[(RS)-(eth-oxy)-phenylphosphinyl]-D-xyio-hexofuranoses (85), which was separated by thin-layer chromatography (t.l.c.). Similarly, (5RS)-5,6-di-deoxy-1,2 - O - isopropylidene- 5 -C- [(RS)-(methoxy)phenylphosphinyl]-... 

When either of the two methods in the previous Subsection is employed in order to introduce a phosphino (or phosphinyl) group at C-5 of 5-deoxy-D-xyZo-hexofuranoses, only 5-deoxy-5-phosphino- (or -5-phos-phinyl)- L-idopyranoses are produced for instance, 50 — 60 (and 64) — 63 (and 65), and 73 — 78 — 85 — 88 — 90. Therefore, in order to prepare hexopyranoses of the D-gluco type having phosphorus in the hemiacetal ring, an alternative approach had to be devised. 

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