Laser Light Scattering Study on Aggregation of Cellulose Diacetate in Acetone

We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.     

二乙酰氧基亚碘酰苯氧化糖基烯合成D-甘露庚糖醇

以五苄基-D-甘露糖为原料,经Wittig反应制得D-甘露庚糖烯（产率88%）,然后在二乙酰氧基亚碘酰苯/LiBr体系下催化氧化糖基烯制得五苄基-D-甘露庚糖醇(产率65%),最后脱苄基得到D-甘露庚糖醇（产率90%）,总得率51%。 方法简便、环保,可用于糖醇的合成。     

Sol-Gel as Reaction Matrix for Bacterial Enzymatic Activity

Sol-gel process is a rapid growing field in material chemistry. The sol-gel matrices (SGM) are basically porous wet-gels or xerogels obtained by the hydrolysis and condensation-polymerisation of metal and semimetal alkoxides, mainly SiO₂ materials. The current study presents the uses of sol-gel glass matrix (SGM) that allow direct entrapment of biomolecules within and at surface, which can be utilized by microorganisms. This glass type is solid, transparent, porous and can be modulated to form a hydrophobic or hydrophilic surface. In view of all these beneficial characteristics of SGM, preliminary data is presented on biofilm formed on thin films of SGM doped with a fluorochrome (fluorescein diacetate). The esterase/lipase activity of E. coli CN ₁₃ and K. oxytoca spp. biofilm grown on top of SGM thin film, doped with fluorescein diacetate, was detected at the level of a single cell by epifluorescence microscopy. In view of these preliminary results, sol-gel glass has a considerable potential as a variable matrix for single bacteria and biofilm investigation.     

Novel transformations of nitraminodiol diacetates

A novel scission reaction of nitraminodiol diacetates of the formula AcO[CH₂N(NO₂) _x CH₂OAc (x = 1–4) in concentrated sulfuric acid to form formaldehyde, nitramide, and 2-nitro-2-azapropane-1,3-diol disulfate was found.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 3, pp 761–762, March, 1996.     

Synthesis of nine-, ten-, and fifteen-membered alkenolides by the oxidative cleavage of the bridging C=C bond in 2-oxabicycloalkenes

Hydroperoxidation of C=C-bridged 2-oxabicycloalkenes in which the five- or six-membered oxacycle is fused with the five-, six-, or twelve-membered hydrocarbon ring was studied. The Cu(OAc)₂-catalyzed decomposition of the resulting hydroperoxides afforded nine-, ten-, or fifteen-membered trans-alkenolides, respectively. The latter compounds were obtained as pairs of regioisomers, with the isomers in which the double bond is more remote from the ether oxygen atom predominating.     

Reaction of triphenylantimony and triphenylbismuth withtert-butyl peracetate

Triphenylantimony and triphenylbismuth diacetates, Ph₃M(OAc)₂ (M = Sb, Bi), were obtained in 50–94 % yields by the reaction of triphenylantimony and triphenylbismuth withtert-butyl peracetate in the presence of acetic acid or acetic anhydride (molar ratio 1 1 1) in toluene.tert-Butyl peracetate oxidizes Ph₃M into alkoxides, Ph₃M(OAc)OBu^t, which at the instant of formation are acylated with acetic acid or acetic anhydride to give the corresponding derivatives, Ph₃M(OAc)₂.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 964–967, May, 1995.This study was financially supported by the Russian Foundation for Basic Research (Grant 94-03-08846).     

A novel and facile iodine(III)-mediated approach for C(5)-acetoxylation of 6-hydroxyflavone and 6-hydroxyflavanones

Oxidation of 6-hydroxyflavone 1 and 6-hydroxyflavanones 2a-c with iodobenzene diacetate (IBD) in acetic acid leads to regioselective acetoxylation, thereby providing a novel and convenient route for the synthesis of 5-acetoxylated products.     

PhI- and polymer-supported PhI-catalyzed oxidative conversion of ketones and alcohols to α-tosyloxyketones with m-chloroperbenzoic acid and p-toluenesulfonic acid

Various ketones were converted to the corresponding α-tosyloxyketones with mCPBA and p-toluenesulfonic acid in the presence of a catalytic amount of iodobenzene. Moreover, secondary alcohols were directly converted to the corresponding α-tosyloxyketones using mCPBA and catalytic amounts of iodobenzene and potassium bromide, followed by treatment with p-toluenesulfonic acid in a one-pot manner. Poly(4-iodostyrene) could be also used as a recyclable catalyst for the same α-tosyloxylation of ketone     

Reactions between cellulose diacetate and alkenylsuccinic anhydrides and characterization of the reaction products

Cellulose diacetate (CDA) with degree of substitution (DS) of 2.4 was dissolved in dimethylsulfoxide and reacted with octadecenyl succinic anhydrides (OSAs) using 1-methylimidazole as a promoter. FT-IR and ¹H-NMR analysis of the reaction products revealed that half-esterification occurred on residual hydroxyl groups of CDA by OSA, providing CDA/octadecenyl succinic acid (OSAcid) half esters at yields of more than 90%. The effects of reaction time and temperature on DS of CDA/OSAcid esters were studied in detail. The higher the reaction temperature, the higher the esterification rate to form CDA/OSAcid half esters. The maximum DS values were 0.41 and 0.33 for CDA/n-OSAcid and CDA/i-OSAcid esters, respectively. The original X-ray diffraction pattern of CDA changed with the introduction of OSAcid substituents into CDA, and CDA/OSAcid esters seemed to have thermoplasticity, depending on DS and the chemical structure of the OSAcids. A soil-embedding test of films of CDA and CDA/OSAcid esters indicated that the CDA/OSAcid esters that were prepared maintained the biodegradability of the original CDA.     

Synthesis of bhimamycin B based on oxidative rearrangement of 4-acetylnaphtho[1,2-b]furan-5-ol to naphtho[2,3-c]furan-4,9-dione

The first total synthesis of bhimamycin B, a novel member of naphtho[2,3-c]furan quinone antibiotics, was achieved by oxidative skeletal rearrangement of 4-acetylnaphtho[1,2-b]furan-5-ol.