Polymerization of 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose and 1,2-O-isopropylidene-α-D-glucofuranose

A new method for preparing D -glucose polymers is described. Isopropylidene derivatives of D -glucofuranose, particularly the 1,2-mono-O-derivative, are treated with Lewis acids, such as boron trifluoride, to eliminate acetone and produce a highly branched polymer with a molecular weight of 12,700. Approximately one isopropylidene unit remains, possibly on the potential reducing end of the glucan. Up to 95% of the polymer units are D-glucopyranoside units indicating that ring expansion occurs during the condensation.     

Synthesis of 1,2:5,6-Di-O-isopropylidene-3-O-[3-(uracil-1-yl)propionoyl]-α-D-glucofuranose and 1,2-Mono-O-isopropylidene-6-O-[3-(uracil-1-yl)propionoyl]-α-D-glucofuranose

1,2:5,6-Di-O-isopropylidene-3-O-[3-(uracil-1-yl)propionoyl]-α-D-glucofuranose and 1,2-mono-O-isopropylidene-6-O-[3-(uracil-1-yl)propionoyl]-α-D-glucofuranose were synthesized.     

Synthesis of some 6-S-heterocyclic derivatives of 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose

We applied nucleophilic substitution to 6-O-tosyl-1,2:3,4-di-O-isopropylidene-α-D-galactopyranose using sulphur nucleophiles and obtained 6-S-derivatives of 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose. We present the physical and spectroscopic characterization of these heterocyclic compounds as well as other related compounds obtained by substitution, using other substrates. The conformational studies of all products are presented and discussed.     

Thermal Rearrangement of 5,6-Epimino-5,6-dihydro-β-ionone and Derivatives

Thermolysis of 5,6-epimino-5,6-dihydro-β-ionone ( 1 ) and its N-methyl derivative ( 2 ) leads to their monocyclic isomers 6 and 10 , respectively, presumably due to a direct [1,5]-H shift; on prolonged heating, these isomers are converted easily into pyrrole derivatives. In contrast, the thermoisomer 12 resulting from 5,6-(N-methoxycarbonyl)epimino-5,6-dihydro-β-ionone ( 3 ) by the same mechanism, does not undergo further ring transformation, but equilibrates with its more stable tautomer 13 .     

Synthesis of 1,2:5,6-Di-O-isopropylidene-3-O-[3-(5-fluorouracil-1-yl)-propionoyi]-α-D-glucofuranose and its antitumor activity

In order to provide a less toxic 5-fluorouracil derivative, 1,2:5,6-di-O-isopropylidene-3-O-[3-(5-fluorouracill-yl)-propionoyl]-α-D-glucofuranose, which was the derivative of 5-fluorouracil combining indirectly to 3-position of diacetoneglucose, was synthesized, and its antitumor activity was tested.     

Photochemische Reaktionen 122. Mitteilung [1]. Zur vinylogen β-spaltung von epoxy-enonen: Photoisomerisierung des 3,4:5,6-diepoxy-5,6-dihydro-β-jonons

Vinylogous β-Cleavage of Epoxy-enones: Photoisomerization of 3,4: 5,6-Diepoxy-5,6-dihydro-β-ionone On ¹n,π*-excitation (λ>347 nm), 3,4:5,6-diepoxy-5,6-dihydro-β-ionone ((E)- 3 ) shows the typical behaviour of α,β-unsaturated γ,δ-epoxy ketones furnishing the (Z)-enone 3 and by C(γ),O cleavage of the oxirane the dihydrofuryl ketone 10 and the cyclohexanones (E/Z)- 11 . However, on ¹π,π*-excitation an unexpected type of transformation is observed: (E)- 3 is isomerized to the four aliphatic triketones 5 – 8 as the main products. To a smaller extent the allene diketone 9 is formed by a known type of isomerization as well as (Z)- 3 . As the starting material for the preparation of (E)- 3 , the known epidioxy-enone (E)- 4 was used. In addition to (E)- 3 , (E)- 4 gives the aliphatic triketone 6 and the hydroxyenone 15 by thermal or catalytic isomerization.     

Conformational analysis of 1,2:5,6-diepithio-3,4-di-o-acetyl-hexitols

Conformational studies of acetylated open chain hexitol derivatives, possessing similar structures but differing in their configuration have been made by analysing their NMR spectra. It is shown, that the carbon chain of all three (manno-, ido-and gluco-) isomers is present in a non planar non zig-zag conformation, containing the acetoxy groups at C-3 and C-4 in a trans relation.     

Crystal Structure of 1，2：5，6－Di－O－isopropylidene－α－D－glucofuranosyl N，N－bis（2－chloroethyl） Phosphordiamidate

ＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ１，２：５，６－Ｄｉ－Ｏ－ｉｓｏｐｒｏｐｙｌｉｄｅｎｅ－α－Ｄ－ｇｌｕｃｏｆｕｒａｎｏｓｙｌＮ，Ｎ－ｂｉｓ（２－ｃｈｌｏｒｏｅｔｈｙｌ）ＰｈｏｓｐｈｏｒｄｉａｍｉｄａｔｅＣｈｅｎＲｕ－Ｙｕ；ＣｈｅｎＸｉａｏ－Ｒｕ（...