Subject acid anhydrides

With acid anhydrides, the exothermic reaction yields similat products, subject to the limitation on n. For higher anhydride ratios, condensed acylates form. If n = 3, the result is (R 0Ti(00CR)2)20 if n = 4, then ((RC00)2Ti)20 forms. Phthahc anhydride does not give a cychc product ... 

Acyl transfer from an acid anhydride to an alcohol is a standard method for the preparation of esters. The reaction is subject to catalysis by either acids (H2SO4) or bases (pyridine). 

Reaction of anthanilic acid 112 with acid anhydrides afforded the corresponding imide derivatives 113. Subjecting 113 to intramolecular Wittig cyclization has been achieved by treatment with A-phenyl(triphe-nylphosphoranylidene)etheneimine in toluene or dioxane whereby the corresponding pyrroloquinolines 116 were obtained (94TL9229). The intermediate 115 resulting from the rearrangement of 114 could be isolated when the reaction was done at room temperature (Scheme 22). 

When a nonproteinogenic unsaturated amino acid was subjected to the Sharpless asymmetric epoxidation, 49 was formed (87TL3605). It is known that AAs are converted with phosgene into A-carboxy-a-amino acid anhydride (NCA) derivatives. Unexpectedly, A-protected dehydroaspartic acid gave l,3-oxazine-2,6-dione-4-carboxylic acid under such conditions (88CL1473). 

SMANCS (Styrere-co-maleic acid/anhydride polymer bound to neocarzinostatin Neocarzinostatin (an antitumor protein) Amide bond between polymer carboxyl and protein amino None N/A SMANCS showed anticancer activity against many tumor cell lines, and had lower IC50 values than five other anticancer agents tested Liver tumors reduced more than 50% after 6 months in human subjects 15, 56, 57... 

On another front, the mixture of allylic alcohols 512 and 513 was converted by reaction with methanesulfonic acid anhydride in the presence of triethylamine to a mixture of the corresponding mesylates, which were subjected collectively to methanolysis to afford 514, and none of the allylic ether epimeric at C-3 was isolated. N Debenzylation of 514 followed by a classic Pictet-Spengler cyclization then afforded ( )-buphanisine (361) (208). 

A mixture of 10.0 g of dehydro-epi-androsterone, 40 ml of pyridine and 20 ml of oenanthic acid anhydride was warmed for 2 h on a steam bath. About 10 ml of water were added and the mixture was warmed for a further 30 min. The reaction mixture was then subjected to a steam distillation. The resulting mixture was extracted with ether and the extract was successively washed with dilute sodium hydroxide solution, sodium carbonate solution and water. 

When D, L-alanine A-carboxylic acid anhydride was subjected to polymerisation with triethylaluminium as the catalyst, the polymer formed, polyalanine, was found [168,174] to consist of two fractions a water-insoluble fraction which was rich in isotactic sequences and a water-soluble atactic fraction. This indicated that some stereoselective polymerisation had occurred [75]. 

Since oxiranes are representative heterocyclic monomers containing an endo-cyclic heteroatom, and the most commonly polymerised of such monomers, they have been subjected to copolymerisations with heterocyclic monomers containing both an endocyclic and an exocyclic heteroatom. Coordination copolymerisations of heterocyclic monomers with different functions are focused on oxirane copolymerisation with cyclic dicarboxylic acid anhydride and cyclic carbonate. However, the statistical copolymerisation of heterocyclic monomers with an endocyclic heteroatom and monomers with both endocyclic and exocyclic heteroatoms have only a limited importance. Also, the block copolymerisation of oxirane with lactone or cyclic dicarboxylic acid anhydride is of interest both from the synthetic and from the mechanistic point of view. Block copolymerisation deserves special interest in terms of the exceptionally wide potential utility of block copolymers obtained from comonomers with various functions. It should be noted, however, that the variety of comonomers that might be subjected to a random, alternating and block polymerisation involving a nucleophilic attack on the coordinating monomer is rather small. 

Ohtsuru et al. (25) have recently investigated the behavior of phosphatidylcholine in a model system that simulated soy milk. They used spin-labelled phosphatidylcholine (PC ) synthesized from egg lysolecithin and 12-nitroxide stearic acid anhydride. The ESR spectrum of a mixture of PC (250 yg) and native soy protein (20 mg) homogenized in water by sonication resembled that observed for PC alone before sonication. However, when PC (250 yg) was sonicated in the presence of heat-denatured soy protein (20 mg), splitting of the ESR signal occurred. On this basis, they postulated the existence of two phases PC making up a fluid lamella phase and PC immobilized probably due to the hydrophobic interaction with the denatured protein. In a study of a soy-milk model, Ohtsuru et al. (25) reported that a ternary protein-oil-PC complex occurred when the three materials were subjected to sonication under the proper condition. Based on data from the ESR study, a schematic model has been proposed for the reversible formation-deformation of the ternary complex in soy milk (Figure 2). 

Chan-Yeung and Malo, 1993). They fall into two groups chemicals, the subject of this book, such as isocyanates or acid anhydrides, and complex biological materials, such as rat urine or flour. 

Graft copolymers were also produced by bubbling alkylene oxides through starch solutions in dimethyl sulfoxide in the presence of potassium naphthenate.2888,2889 Another approach involved grafting polyethylene oxide) to starch. Polyethylene oxide) was converted into a chloroformate derivative and subjected to a reaction with starch alkoxide 2890 Poly(alkylene glycol) could be grafted onto starch by means of cyclic aliphatic acid anhydride in the presence of 4-toluenesulfonic acid 2891 The products were water soluble. 

PAI with a deflnite head-to-tail backbone can be prepared by condensation of trimelliric acid anhydride with 4-amino-4-nitrodiphenyl ether. Then the nitro group is reduced to give a monomer having amine and acid functional groups. This monomer is subjected to direct polymerization. The procedure is useful for the preparation of dissymmetric polymers. Further compounds with amino groups and nitro groups are 3-nitroaniline, 2-methyl-5-nitroaniline, and, 3-nitromesidine, i.e, 2,4,6-trimethyl-3-nitro-aniline. 

Aryl halides are frequently prepared from the corresponding aryldiazonium salts by diazotation procedures. However, diazonium salts can be subjected directly to very mild Heck arylation conditions, which deliver coupled products (entry 19). Preferably, the reaction is executed in nonaqueous solvents such as acetonitrile, acetone, or methylene chloride with sodium acetate as base and with palladiumbis(dibenzylideneacetone) as catalyst. Alternatively, a combination of the amine and f-butyl nitrite, in a mixture of acetic acid and monochloroacetic acid, can provide the desired product directly, which makes the isolation of a diazonium salt unnecessary (entry 20). " It is also possible to use aromatic acid anhydrides as oxidative addition precursors (entry 21). Clearly, anhydrides are very interesting starting materials for a number of Heck reactions due to price and absence of halide salt formation. 

Trimellitates. Trimellitates, the esters of trimellitic anhydride (1,2,4-ben-zenetricarboxylic acid anhydride), are characterized by low volatility. This property increases the service life of a PVC compoimd subjected to elevated temperatures for long periods of time and reduces fogging. The most important trimellitates are trioctyl trimellitate (TOTM) and tri-isononyl trimelliate (TINTM). Trimellitates are most commonly used for PVC wire insulation, often in conjunction with phthalates. 

Apart from the arene substrate and an alkyl halide or acyl halide/acid anhydride, Friedel-Crafts alkylations and acylations most often involve a Lewis acid promoter in the form of a metal halide, like AlCl. Several species may function as the active electrophile, and both acyl halide/metal halide complexes and acylium ions have been observed experimentally. The complex forming ability of these metal halides complicates all mechanistic evaluations, and Friedel-Crafts reactions have rarely been the subject of quantum chemical mechanistic studies. 

Our objective was to develop a general method to prepare any amide or ester derivatives of zein. Zein has free alcohol and amine groups that are capable of reacting with anhydrides or acid chlorides. The conunon solvents for zein, such as alcohol/water mixtures prohibit such reactions because these solvents will react with anhydride and acid chloride. To circumvent this problem, we dissolved zein in dimethylformamide (8) and this clear solution was subjected to various reactions. Thus, our primary objective is to synthesize various esters/amides of zein by reacting with acid anhydrides and acid chlorides. Om second objective is to mold these derivatives into bars and the mechanical properties were determined. 

Therefore the contribution of substrate binding to the reaction rate is partially due to a change in the molecularity of the reaction. The intermolecular reaction of the two substrates is replaced by an intramolecular reaction of an enzyme-substrate complex. The consequences can be clarified by using model compounds which have all the reactive groups within their molecules and, thus, are subjected to an intramolecular reaction. Their reactivity can then be compared with that of the corresponding bimolecular system and the results expressed as a ratio of the reaction rates of the intramolecular (ki) to the intermolecular (k2) reactions. Based on their dimensions, they are denoted as effective molarity . As an example, let us consider the cleavage of p-bromophenylacetate in the presence of acetate ions, yielding acetic acid anhydride ... 

Alkyd resins completely based on renewable resources have been the subject of a few studies. EP 0741 175 A2 to Hoechst describes waterborne alkyd emulsions based on renewable resources. The patent describes the use of sorbitol (easily derived from starch) as the polyhydric alcohol part and succinic acid anhydride as the polycarboxylic acid part. Hajek described the use of sorbitol and xylitol in alkyd resin synthesis, whereas Bagchi et al. described the partial replacement of conventional polyols, i.e., glycerol and pentaerythritol, by sorbitol. 

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