1,2:3,5-di-O-benzylidene

C22H22O7 398.412 Mp 145-146°. Mg -42.2 (CHCI3). 2,3 4,5-Di-0-benzylidene, 1-tosyl 2,3 4,5-Di-O-benzylidene-I-O-tosyl-p-D-fnicto-pyranose... 

Di-0 -benzylidene-5-deoxy-D-arabinitol, D-40 2,3 4,5-Di-0-benzylidene-l-deoxy-D-xylitol, D-385 2,3 4,5-Di-O-benzylidene-l-deoxy-DL-xylitol, D-385 2,3 4,5-Di-O -benzylideneribitol, R-94... 

Condensation of 2,3 4,5-di-O-benzylidene-D-ribose or related aldehydo-D-ribose or -D-glucose derivatives with a number of active methylene compounds, e.g., pentane-2,4-dione, gave the expected Knoevenagel condensation products, which all showed antiviral activity and cytotoxicity the most effective against herpes simplex virus was the ribose-2,4-pentanedione derivative (34) titanium... 

The conformational flexibility postulated for the 2,4 3,5-diacetals of mannitol would disappear in acetals prepared from higher aldehydes and therefore possessing substituents at the acetal carbon atoms, but the status of such acetals is at present obscure., Two isomers of l,6-dichloro-l,6-dideoxy-2,3,4,5-di-O-ethylidene-D-mannitol are known, but the structures have not been determined. Two stereoisomers with the 2,4 3,5-structure and related to the H-inside and 0-inside conformations LVI and LVII, respectively, are clearly possible, but the structures 2,3 4,5 and 2,5 3,4 must also be considered. There is considerable scope for more work on 2,3,4,5-diacetals of mannitol, and confirmation of the structure XLVII advanced by Ness, Hann and Hudson for their mono-O-benzylidene-mono-O-methylene derivative is a necessary step in the assessment of the relative stability of the different structural types. 

Other examples of C-1 substituted glycals are compounds (1) and (2) which have been obtained, respectively, by eliminations from tri-O-benzoyl-L-rhamno-pyranosyl nitrile and 2,3 4,5-di-0-benzylidene-L-sorbofuranose. The former product, on debenzoylation, gave a diol which could be oxidized to the conjugated enone or the 7-pyrone compound (2) was derived by use of butyl-lithium. ... 

Di-O-benzyI-L-ri7 0 -hexos-5-ulose, H-KG 2,3 4,5-Di-0-benzylidene-D-alIitol, A-75 2,3 4,5-Di-0-benzylidene-D-arabinitol, A-792 2,3 4,5-Di-0-benzylidene-D-arabinose diethyl dithioacetal, A-852 2,4 3.5-Di-0-benzylidene-D-arabinose diethyl dithioacetal, A-852 1,2 3,4-Di-0 -benzylidene-5-deoxy-D-arabinitol, D-40 2,3 4,5-Di-0 -benzylidene-1 -deoxy-o-xylitol, D-385 2,3 4,5-Di-0-benzylidene-l-deoxy-DL-xylitol, D-385 3,5 4,6-Di-D-benzylidene-I,2-dideoxy-L-xyfo-hex-l-enitoI, D-579 l,3 4,6-Di-0-benzylidene-2,5-di-0-mesyl-i>mannitoI, M-25... 

Di-0-benzylidene-p-D-fnictopyranose, F-84 2,3 4,5-Di-0-benzylidene-l-0-methyl-p-D-fructopyranose, F-84 2,3 4,5-Di-0-benzylidene-l-0-tosyl-p-D-fructopyranose, F-84 l,2 4,5-Di-0-cyclohexylidene-p-D-fnictopyranose, F-84 l,2 4,5-Di-0-isopropylidenefructopyranose D-form 3-O-Benzyl, D-714 l,2 4,5-Di-0-isopropylidenefructopyranose D-form, D-714 l,2 4,5-Di-0-isopropylidenefructopyranose D-form, D-714 2,3 4,5-Di-0-isopropylidenefructopyranose D-form, D-715 2,3 4,5-Di-0-isopropylidenefructopyranose D-form, D-715 3,4 5,6-Di-0-isopropylidene-D-ara6BM7-hex-2-uIosonic acid, H-111 l,2 4,5-Di-0-isopropylidene-3-0-mesyl-P-D-fructopyranose, D-714 l,2 4,5-Di-0-isopropylidene-3-C-methyl-p-D-fructopyranose, M-248 2,3 4,5-Di-0-isopropylidene-l-0-methyl-P-D-fructopyranose, D-715 2,3 4,5-Di-0-methylenefructopyrauose -D-form, D-729... 

This section is completed with a brief review of the synthesis and properties of this epimer (20) of the precursor of thiazole in bacteria. This pentulose is conveniently accessible by an unconventional route (Scheme 19). Methyl 2,3 4,6-di-O-isopropylidene-a-D-mannopyranoside, readily available from methyl ot-D-mannopyranoside, is converted to the ketonic glycoside by butyllithium in 91% yield, following a method first published by Klemer and Rodemeyer43 and scaled up by Horton and Weckerle.44 This was converted by means of lithium hydroxide in a water-ether mixture into 3,5-0-benzylidene-l-deoxy-D-eryf/iro-2-pen-tulose in 55% yield. Hydrolysis to the free pentulose (20) proceeded in 73% yield in aqueous acetic acid. This product was obtained as a syrup with a characteristic absorption band at 1705 cm 1 as a film. Thus, there is a fair proportion of the open-chain ketone under these conditions, as with the D-threo epimer.45... 

Deoxy-l-fluoro-L-glycerol (18) has been prepared by, among other methods, the treatment of 3,4-0-benzylidene-2,5-0-methylene-l,6-di-O-p-tolylsulfonyl-D-mannitol107 (17) with tetrabutylammonium fluoride in acetonitrile, followed by removal of the benzylidene group, periodate oxidation, reduction with borohydride, and hydrolysis. 1,6-Dideoxy-l,6-difluorogalactitol108 was obtained by treatment of 2,3 4,5-di-0-isopropylidene-l,6-di-0-(methylsulfonyl)galactitol with tetra-... 

Closely related to the synthetic work reported in the previous section is the incorporation (131) of a 2,5-anhydro-3,4Hdi-0-methyl-D-mannitol residue (Figure 15) into the 18-crown-6 derivative d-91. Other derivatives of D-mannitol that have been built into crown ether receptors include l,4 3,6-dianhydro-D-maiuiitol (132), l,3 4,6-di-0-methylene-D-marmitol (13 134), and 1,3 4,6-di-O-benzylidene-D-mannitol (134). Examples of chiral crown compounds containing these residues include dd-92, dd-93, d-94, and d-95. Although not derived from carbohydrates—but rather (135) from the terpene, (-t-)-pulegone—... 

Primary alcohol groups in several protected ribo-, fructo- and glucofuranoses including 2,3,4-tri-O-benzoyl-D-glucose, 1,2-isopropylidene-D-xylo-furanose, 2,3 4,5-di-0-isopropylid-ene-D-fructopyranose, methyl 2,3-O-isopropylidene-P-D-ribofuranoside, l,2-0-isopropylidene-3,5-0-benzylidene-D-glucofuranose and... 

A new synthesis of glycosyl azides has been reported which involves sequential treatment of an aldose, in which all hydroxy-groups other than that at C-1 are blocked (acetals or ethers), with HMPT and mesityleneoxytris(dimethylamino)-phosphonium azide. The glycosyl azides are usually formed in overall yields of 65-80% yields and the 1,2-cw-isomers are formed exclusively. The method has been applied successfully to 2,3 5,6-di-O-isopropylidene-D-mannofuranose and its a//o-isomer, 2,3-0-isopropylidene-5-0-trityl-D-ribofuranose, 2,3 4,6-di-(9-benzylidene-D-mannopyranose, and 2,3,5-tri-O-benzyl-D-arabinofuranose. The products are useful for the synthesis of nucleoside analogues. 

Benzyl 2,6-di-O-benzyl-p-D-galactopyranoside, B-15 Benzyl 2,3-di-O-benzyl-p-D-galactopyranosiduronic acid, G-210 Benzyl 2,3-di-O-benzyl-a-D-glucopyranoside, B-16 Benzyl 2,3-di-O-benzyl-p-D-glucopyranoside, B-16 Benzyl 2,3-di-0-benzyl-a-D-x y/o-hexopyranosid-4-ulose, H-104 Benzyl 2,6-di-0-benzyl-a-D-x y/o-hexopyranosid-4-ulose, H-104 Benzyl 2,3 4,6-di-0-benzylidene-a-D-mannopyranoside, B-19 Benzyl 2,6-di-0-benzyl-3,4-0-isopropylidene-p-D-galactopyranoside, B-15 Benzyl 2,3-di-0-benzyl-p-L-zAreo-pentopyranosid-4-ulose, P-46 Benzyl 2,4-di-0-benzyl-a-D-rhamnopyranoside, B-20 Benzyl 3,4-di-0-benzyl-a-D-rhamnopyranoside, B-20 Benzyl 2,4-di-0-benzyl-a-L-rhamnopyranoside, B-20 Benzyl 3,4-di-0-benzyl-a-L-rhamnopyranoside, B-20 Benzyl 3,5-di-O-benzyl-p-D-ribofuranoside, B-21 Benzyl 2,3-di-0-benzyl-6-0-trityl-a-D-glucopyranoside, B-16 Benzyl 2,3-di-O-benzyl-6-0-trityl-a-D-x y/o-hexopyranosid-4-ulose, H-104 Benzyl 4-0-(2,4-di-0-benzyl-p-D-xylopyranosyl)-2,3-di-0-benzyl-a-D-xylopyranoside, X-80... 

O -Benzoyl-1,2 4,6-di-0 -benzylidene-a-D-glucopyranose, B-26 3-0-Benzoyl-l,2 5,6-di-0-cyclobexylidene-a-D-glucofuranose, C-190 3-0-Benzoyl-l,2 5,6-di-0-isopropylidene-a-D-glucofuranose, D-717 6-0-Benzoyl-2,3 4,5-di-0-isopropylidene-D-glucose diethyl dithioacetal,... 

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