Other Anhydrides

Other Anhydrides. — The 1,6-anhydro derivatives of aldohexoses have been reviewed, and the application of empirical force-field calculations to all eight of these anhydrides has closely reproduced the conformational variations observed in crystal structures, but the conformational differences in the five-membered ring are not so well predicted. The yield of l,6-anhydro-/3-D-mannopyranose from the pyrolysis of ivory nut meal is improved by 50% by predigestion with acid.  

In a substantial paper, Sinclair has examined the action of base on all six methyl di-O-mesyl-a-D-glucopyranosides. In all cases except one, a 2,3- or 3,4-anhydro mesylate is formed initially, but on further reaction (usually under more rigorous conditions) these are either isomerized to 3,6-anhydrides or converted into dianhydrides depending on the position of the remaining mesyl substituent. In the case of the dimesylate (28), a mixture of the 2,3- and 

6- anhydrides 1(29) and (30) respectively] was formed initially. The 2,3-anhydro-6-mesylate was then subsequently converted into a mixture of the 2,6 3,4-dianhydro-altroside (32) and 2,6-anhydro-altroside (33), whereas the 

A review of the preparation, structures, and stereochemistry of cyclic acetals of the aldoses and aldosides has appeared. Pyridinium toluene-p-sulphonate has been reported to be a mild catalyst for the formation and cleavage of dioxolane-type acetals, although no carbohydrate examples were quoted. Acetals and ketals of carbohydrates have been used as co-agents to introduce chirality into the products of sodium borohydride reduction of acetophenone, propiophenone, etc  

A study of the oleum-catalysed acetonation of L-sorbose has shown that 71-83% of ketal mixtures containing 92-94% of 2,3 4,6-di-(9-isopropylidene-L-sorbose can be obtained. Lowering the temperature from 0 to — 10°C increased the yield by 3%, but increasing the time of reaction above 20 min had little effect on purity or yield. A continuous-flow method for production of sorbose acetonide has been optimized and yields of 11,6% obtained. Room temperature reaction of lactose with 2,2-dimethoxypropane in DMF gives mainly 4,6 -O-isopropylidene lactose, whilst at reflux the same reaction gave 45% of the 

Other Anhydrides.- Ring-opening polymerizations of 1,3-anhydro- 

6-tri- -(p-bromobenzyl)-6-D-glucopyranose, trl- -benzyl-a-D-glucopyranose,1, -anhydro-2,3-0-cyclohexylidene 

6-Anhydro-B-D-glucopyranose has been identified as a product from hydrothermolysis of cellulose and its degradation in aqueous solution at 200-240°C examined.A mild procedure for the synthesis of 1,6-anhydrohexopyranoses involves treatment of the pentabromophenyl g-glycosides (obtained in two steps from the B-peracetates) with tetrabutylammonium hydroxide at 20°C, followed by 

Reogertts HBr-HOAc a, -McOH Ui, MeONa-MeOH iVj Bn.Bv-NcU-l-DMP Vj HOAc  

D-Fructose, or Inulin, is converted by anhydrous hydrogen fluoride into a mixture of dlfructose dlanhydrldes. Six were Isolated, five being known compounds, but two of these were assigned the revised structures a-D-fructopyranose-g-D-fructopyranose 1,2  

Other Anhydrides.- The synthesis and Lewis acid catalyzed ringopening polymerization reactions of 1,M-anhydro-2,3-di- -benzyl-a-L- 

The stereoselectivity achieved in the synthesis of C-6 chirally deuterated hexopyranoses by sequential C-6 photobromination - tri- 

6- -mycoloyl- and -corynomycoloyl-a-D-galactopyranoside, analogues of trehalose glycollpids, have been synthesized by sequential introduction and displacement of tosylate groups from C-6 and C-6 of a 2,3,2, 3 -tetra-0-benzyl-protected galactosyl galactoslde. 

L-Sorbose has been converted into a mixture of six disorbose dianhydrides (two of which were previously known) by treatment with anhydrous hydrogen fluoride, L-sorbofuranosyl fluoride being the intermediate. Five of the dianhydrides were 1,2 2,1 -Isomers [e.g., compound (19)] differing in ring size and anomeric configuration, while the sixth was the 2,1 3,2 -dianhydrlde (20). 

Such dianhydrides were also formed on treatment of L-sorbose with 

Other Anhydrides.—A D-glucosyltransferase from Aspergillus niger acted on maltose to give, among other products, 1,6-anhydro-p-D-glucopyranose (1 %) by an intramolecular transfer reaction. A series of oligomeric ethers (88) was 

Treatment of methyl 2,3-di-0-methyl-6-0-toluene-p-sulphonyl-a-D-gaIacto-pyranoside with hot aqueous, alcoholic sodium hydroxide afforded methyl 4,6-anhydro-2,3-di-0-methyl-a-D-gaIactopyranoside in a yield of 84%. The 

The formation of 2,5-anhydropentose dibenzyl dithioacetals from pentose dibenzyl dithioacetals and that of 2,5-anhydro-D-allose derivatives via diazotiza-tion are discussed in Chapters 10 and 8, respectively. 

Other Anhydrides.—Hungarian workers have shown that treatment of 1,2,3,4-tetra-0-acetyl-/3-D-glucopyranose with stannic chloride affords tri-O-acetyl-l,6-anhydro-j8-D-glucopyranose by way of an isolable complex containing the 

Application of the Corey-Winter reaction to compound (10) did not give 

Compounds (12)—(14) are reported to isomerize to give 1,4-anhydro products on treatment with mercury(ii) bromide. The relative rates decreased in the order (12) (13) (14). l,4 3,6-Dianhydro-a-D-glucose (15) was produced together with levoglucosan and l,6-anhydro-3,4-dideoxy-j3-D-5 / cero-hex-3-enos-2-ulose (16) on acid-catalysed pyrolysis of glucose, amylo-pectin, and cellulose, and the dianhydride could be transformed into the enone 

Voznyi and A. F. Bochkov, Tezisy Doklady - Vses. Konf. Stereokhim. Konform. Anal, Org. Neftekhim. Sint, 3rd, 1976, 75 (Chem, Abs., 1978, 88, 170 408y). 

Phase transfer catalysis has been used in the methylenation of carbohydrates methyl 4,6-0-benzylidene-glucosides and galactosides gave the /raw -fused 2,3-acetals in about 60% yield with methylene dibromide and alkali. Methyl jS-D-ribofuranoside gave the fully substituted dimeric compound (1), and its 5-trityl derivative afforded the monomeric 2,3-acetal as anticipated,  

Other Anhydrides.—The enones (42) and (43) have been prepared by oxidation of the corresponding allylic alcohols with manganese dioxide. Whereas the oxiran derivative (44) afforded the allylic alcohol (45) on treatment with butyl-lithium, the /yxo-isomer (46) gave the 2-substituted glycal (47). Enols with equatorially oriented hydroxy-groups were obtained when the enones (42) and (43) were reduced with sodium borohydride. 

Reagents , Et NCI--Et,N-ClCH3CHjCl ii, Bu OK-DMSO iii, H -Pd-C iv, AcjO-py V, AC2O-ACOH-H2SO4 

It has been shown that 1,6-a.nhydro-L-gIycero-D-manno-heptopyreinose is one of the products formed on acidic hydrolysis or methanolysis of an i.-glycero-D-/77a o-heptose-containing polysaccharide from Bordetella pertussis endotoxin. Alkaline treatment of 2-chlorophenyl j6-maltotrioside deca-acetate afforded l,6-anhydro-j3-maltotrioside, which was isolated as the crystalline nona-acetate.  

2 Other Anhydrides - The readily available diol 3 has been converted into the 

6- anhydro-derivatives 4 and 5 (camphorsulfonic acid, toluene, reflux) in a 7 1 ratio and the galactopyranoside diol 6 afforded a 1 1 ratio of the corresponding 

6- anhydro-compounds under the same conditions. An acid-catalysed rearrangement of D-galactal has afforded the unsaturated 1,6-anhydro-sugar 7. The Sharpless asymmetric dihydroxylation applied to the terminal alkene in 2-vinylfuran, followed by further oxidation reactions, has led selectively to both 

The cyclohexylidenation of D-mannose diethyl dithioacetal aimed at the preparation of the fully 0-protected aldehydo-D-ma.nnose derivative 8 has been described.  

A detailed comparative study on the benzylidenation of D-arabinose diethyl-dithioacetal with benzaldehyde dimethylacetal and catalytic TsOH or with benzaldehyde in the presence of HCl or ZnCb has been published, and the benzylidenation of methyl a-D-mannopyranoside with benzaldehyde and TsOH has been improved, with yields of acetal 9 72%. Transacetalation of fully 6-0-pivaloylated a-, P-, and y-cyclodextrins with benzaldehyde dimethylacetal and catalytic camphorsulfonic acid gave mono-benzylidene products 10. Reductive ring-opening (LAH/AIQ3) of compounds 10 afforded predominantly the 2 -0-unprotected derivatives 11.  

2 Other Anhydrides. - Stereoselective chemical and chemoenzymatic approaches to the preparation of 1,6-anhydrohexopyranoses have been reviewed, and base treatment of pentabromophenyl glycosides has been investigated as an improved procedure for the synthesis of 1,6-anhydro sugars. Treatment of O-benzylated-3-O-acetyl-glycosyl chlorides with base (KO Bu, THF) has allowed syntheses of l,3-anhydro-2,4,6-tri-0-benzyl-P-D-talopyranose, l,3-anhydro-2,4-di-C -benzyl-a-L-arabinopyranose and 1,3-anhydro-2,4-di-0-benzyl-6-deoxy-P-L-talopyranose. The theoretical solution conformation of methyl 3,6-anhydro-a-D-galactopyranoside has been studied using ab initio calculations. The computed conformation was similar to that adopted in the crystal (X-ray analysis).  

In acid solution, l-deoxy-o-tAreo-pentulose forms the dimeric 24, and the stereoselective synthesis of di-P-D-fructopyranose 1,2 2,1 -dianhydride has been achieved by way of a fructopyranosyl fluoride. The Michael addition of thiols, alcohols and C-nucleophiles to levoglucosenone has been used in the synthesis of analogues of the herbicide l,6-anhydro-4-0-benzyl-3-deoxy-2-( -methyl-P-D-ri o-hexopyranose.  

Paulsen, M. Springer, F. Reck, E. Meinjohanns, I. Brockhausen and H. SdansdaXet, Uehigs Arm. Chem., 1995, 53. 

Raaijmakers, E.G. Amouts, B. Zwanenburg, G.J.F. Chittenden and H.A. van Doren, Reel Trav. Chim. Pays-Bas, 1995,114,301. 

Miethchen, M. Hein, D M Naumann and W. Tyrra, Uebigs Arm. Chan., 1995, 1717. 

Mading, H. Kasper, J. Zessin, M. Gnauck, F. Fuchtner, P. Brust and J. Stein-bach, Wiss.-Tech. Ber. - Forschungszent. Rossendorf, 1999,141 Chem. Abstr., 2000, 132,265 352). 

Palazzino, C. Galeffi, E. Federici, F. Delle Monache, M.F. Cometa and M. Palmery, Tetrahedron, 2000,55,411. 

Liptak, A. Borbas, L. Janossy and L. Szilagyi, Tetrahedron Lett., 2000,41,4949. 

Bessodes, C. Dubertret, G. Jaslin and D. Scherman, Bioorg. Med. Chem Lett., 

Shizuma, H. Imamura, Y. Takai, H. Yamada, T. Takeda, S. Takahashi and M. Sawada, Chem. Lett., 2000,1292. 

Treatment of T,2,6,6-tetra-d-tosylsucrose (12) with base afforded the l 4 3 6 3,6-trianhydro-2-0-tosylsucrose (13) showing that 3,6-anhydro-forma- 

Reagents i, H NOH ii, NaOMe iii, MeCHO-H iv, EtSH-BFj v, HgCl -CdCOj 

The reaction of sucrose with triethylboroxlne [(EtBO) -py-PhMe, 

Hexopyranosldes (D-gluco, D-manno, D-galacto, 2-acetamido-2-deoxy-D-gluco. and a,a-trehalose) were converted into their 3j6-anhydrldes by treatment of their previously reported stable crystalline 6-oxytris(dimethylamino)phosphonium hexafluorophosphate salts with alkali (MeOH-MeONa).The four possible 3,6-anhydro-hexofuranoses, together with their triacetates, methyl glycosides, and glycoside diacetates, have been synthesized, mainly from the known 3 6-anhydrohexopyranoses, and equilibria between the anomerlc 

2j5-Anhydro-D-allose, a useful substrate for C-nucleoside synthesis, has been prepared from D-rlbose via the Intermediate (19).  

Vakorina and Yu.N.El Kin, Khim. Prir. Soedln., 1982, 484 (Chem. Abstr., 

Marek and J.Jary, Sb. Vys. Sk. Chem.-Technol. Praze, Org. Chem. Technol., 

Opening of the anhydro-ring of 2,3,4-tri-C -acetyl-l,6-anhydro-j3-D-gluco-pyranose with titanium tetrachloride and alkoxytitanium trichlorides has been examined. Data have been presented to show that l,6-anhydro-3,4-dideoxy-jS-D-5-/ycero-hex-3-enopyranos-2-ulose(levoglucosenone) is not principally derived from 1,6-anhydro-jS-D-glucopyranose on acid-catalysed pyrolysis of cellulose. It appears that l,6-anhydro-j8-D-glucopyranose itself is not a primary product of cellulose pyrolysis, so that the principal mechanism of its formation must involve a precursor still to be identified. 

5-Acetamido-3,5-dideoxy-D-5 /yecro-D- fl/flc/o-nonulopyranose has been shown to exist in equilibrium with the 2,7-anhydride (55) in the presence of dilute 

Fenichel, G. Deak, P. Bako, S. Holly, and Z. Csuros, Acta Chim. Acad. Sci. Hung., 1975, 85, 313 Chem. Abs., 1975, 83, 164 445p). 

4-Anhydroerythritol has been converted into 1,4-anhydro-DL-threitol by chloride displacement of a toluene-p-sulphonyloxy-group. The dimethyl [2]-cryptand (59) has been obtained in a five-step synthesis from pentaerythritol, and was shown to form strong complexes with potassium ions in deuteriochloro-form-carbon disulphide solution.  

6-Anhydro-a-L-ldofuranose (30) has been synthesized from the D-glucofuranose derivative (31), which was converted to the 1,6-anhydrlde (32) following a previously patented procedure the 

Improve yields of l,6-anhydro-6-cellobiose and -maltose, isolated as their hexaacetates in 6l and 78 respectively, have been obtained by alkaline treatment of pentachlorophenyl hepta- -acetyl-6-cellobioslde and -maltoside respectively, these being synthesized in good yield from the glycosyl bromides and sodium pentachloro- 

5-Dianhydro-a-L-gulofuranose (37) has been synthesized by the intramolecular sulphonate displacement reactions shown in 

l -Anhydro-sucrose has been synthesized from 6,6 -di- -trityl- 

The anomeric configurations in a-D-fructofuranose g-D-fructo-furanose 2, 1 2,3 -dlanhydrlde, a product formed in high yield by the action of a D-fructotransferase on Inulln, have been determined from its C-n.m.r. spectrum.A H-n.m.r. study on tosylated derivatives of 1,6-anhydro-g-D-glucopyranose is mentioned in Chapter 20. 

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From a cyanohydrin AC2O, FeCl3, 25-92% yield. Other anhydrides are also effective in this conversion. ... 

Other anhydrides that have been used include dodecenylsuccinic anhydride, which imparts flexibility into the casting, and chlorendic anhydride, where flame-resistant formulations are called for. 

Subsequently both Gastaldi and Peyretti and Schneider performed the reaction with other anhydrides (R" = Et, Pr, iso-Bu). The series was extended by Hopf and Le Fevre and by others ... 

Dimerization of 2-hydroxy-4-methoxybenzaldehyde 208 was carried out using a mixture of pivalic anhydride and sulfuric acid. The product double 1,3-dioxane 209 was obtained in 96% yield (Scheme 98) <20000L1613>. Other anhydrides were less efficient. The product was used for the construction of the core unit of preussomerins <2004TL4877, 2004OBC2483>. 

Preparation of acid anhydrides Acid anhydrides are prepared from carboxylic acids by the loss of water. For example, acetic anhydride is prepared industrially by heating acetic acid to 800 °C. Other anhydrides are difficult to prepare directly from the corresponding carboxylic acids. Usually they are prepared from acid chloride and sodium carboxylate salt (see below). 

Acetic and other anhydrides have been shown to promote the formation of indolizines from pyridinium salts in a cyclization reaction in which the 2,3-bond if formed. Some practicable ways are given in Scheme 18. 

Although this method is rarely used because of the poor yields often associated with it, acetic and other anhydrides have been shown to promote the formation of indolizines from pyridine quaternary salts in a cyclization reaction in which the 2,3-bond of the indolizines is formed.3141-45 This route starts from a quaternary salt of general formula 11 which is acylated and dehydrobrominated in one step to give 12. Heating 12 under reflux with acetic anhydride gives the indolizine 13a or 13b (Method A) (see Scheme 4).31 Alternatively, the quaternary salt can be converted directly into the indolizine by employing triethylamine (Method B).41 Some idea of the scope of the reaction can be gained from Table I. 

No similar effect was observed with other anhydrides. 

It has been suggested that the modification of the protein s isoelectric point could result in an alteration of its pharmacokinetic profile. Avidin acylation was performed by lysine amino group derivatization with succinyl anhydride or other anhydrides, which allowed the isoelectric point to be shifted to more acidic values, depending on the level of modification. Indeed, the protein anionization induced a reduction of accumulation in the liver, but resulted only in a limited prolongation of residence time in the circulation [30, 31]. 

This procedure is capable of considerable variation, by which other indenones may be secured. For example, the benzalphthalide may be replaced by other phthalides made from (a) other aldehydes, or (b) other anhydrides the phenyl-magnesium bromide can be replaced by other Grignard reagents. 

Recently, a new polyanhydride, poly(fatty acid-sebacic acid), has been synthesized. This polyanhydride uses hydrophobic dimers of erucic acid. Some of its physical properties relevant to the fabrication of drug delivery devices are also improved over those of the other anhydrides based on CPP lower melting temperature, higher solubility in solvents, and higher mechanical strength. The erosion of the polymers is dependent on... 

Other anhydrides such as dodecyl succinic anhydride (DDS A) or adducts of DDS A with polyglycols, can also be used for formulating heat cured epoxy adhesives. These have excellent electrical properties and good thermal shock resistance. Anhydride cured epoxies are also useful for bonding plastics, notably polyester such as Mylar.8... 

General Anhydride Synthesis Other anhydrides must be made by less specialized methods. The most general method for making anhydrides is the reaction of an acid chloride with a carboxylic acid or a carboxylate salt. 

Other anhydrides, such as propionic, butyric, and phthalic, have been reacted with wood [18,19] but no data have been published on mechanical properties of these modified woods. 

The photochemistry of phthalic anhydrides has not received a great deal of attention however, if reactivity is analogous to other anhydrides 2 ), photolysis of phthalic anhydride should also provide a convenient route to benzynes. 

At 180°C acetic anhydride reacts with 1,2-dibenzoylaminoethylene to give 2-methyl-imidazole. Although some other anhydrides can take part in this reaction it is not successful for the synthesis of a wide range of 2-substituted imidazoles (70AHC(12)103). 

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