Synthesis anhydrides

An intriguing conversion of MA has been reported by Baumann and Bosshard. In boiling acetic acid, MA and 2-aminopyridine 108 are converted to a dimethylmaleimide 109 in a 70-80% yield. Other tautomeriz-able 2-aminoheterocycles were less effective but the reaction was general. 

Compound 109 can be easily hydrolyzed to dimethylmaleic anhydride 110. It was reported that per 2 moles of MA, approximately 1 mole of 109 was produced. One mole of CO2 was evolved.No CO was measured and the fate of the other carboxyl group of MA was not clear. Stoichiometry of the process is not convincing, requiring more hydrogen in the product if 2MA per product is believed. A detailed study of this interesting reaction appears warranted. 

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Acetic Acid and Anhydride. Synthesis of acetic acid by carbonylation of methanol is another important homogeneous catalytic reaction. The Monsanto acetic acid process developed in the late 1960s is the best known variant of the process. 

Imidazole-4,5-dicarboxylic acid, 1-methyl-decarboxylation, 5, 435 Imidazole-4,5-dicarboxylic acid anhydride synthesis, 5, 435... 

Route (b), using acetylIde ion, has been used for the synthesis of (26) which did Indeed give the right dlastereoisomer of (23) with maleic anhydride. Synthesis... 

M Zaoral. Amino acids and peptides. XXXVI. Pivaloyl chloride as a reagent in the mixed anhydride synthesis of peptides. Coll Czech Chem Commun 27, 1273, 1962. 

The two main resin linkers developed so far are shown in Scheme 18, i.e. tris(alk-oxy)benzylamide- 412 and 4-alkoxybenzylamide-type linkers)341 the former being TFA labile and thus fully compatible with Fmoc/tBu and the latter strongly acid labile and correspondingly compatible with Boc/Bzl chemistry. As shown in the case of the tris(alk-oxy)benzaldehyde handle such handles may be introduced into the C-terminal amino acid ester by reductive amination, and after suitable N -protection coupled to amino-functionalized resins (see Scheme 18). Alternatively, the tris(alkoxy)benzaldehyde-functionalized resin, BAL resin, (see Scheme 14) is used to link the C-terminal amino acid ester by reductive amination. To overcome the difficult acylation of the V -arylamino acid ester derivative on resin (best results with 10 equivalent symmetrical anhydrides), synthesis in solution of the C-terminal dipeptide building block containing the amide handle followed by its attachment to the resin has been proposed)341 ... 

Tasker (1946) Phthalic anhydride synthesis C Air Catalyst on quartz ( ) Granules 1.7-2.0 ... 

Methyl anthraquinone has been obtained by the oxidation of /3-methyl anthracene by several investigators 1 and material of the same origin, obtained by the benzene-extraction of crude commercial anthraquinone,2 has been fully described. As regards the synthesis from phthalic anhydride and toluene, both the preparation and properties of />-toluyl-o-benzoic acid 3 and the complete synthesis 4 have been the subject of several papers. This acid has also been prepared from o-carbomethoxy benzoyl chloride and toluene.5 The phthalic anhydride synthesis of anthraquinone derivatives in general has received considerable attention. An account of this work, together with extensive references, is given by Barnett.6... 

Deshpande, A. M. Natu, A. A. Argade, N. P. Chemo- and regioselective nucleophilic reactions of (brorriorrietliyl) methylrrialeic anhydride synthesis of a-quinoxalinyl- and a-ben-zothiazinylacrylic adds. Heterocydes 1999, 52, 2159-2162. 

Heat exchange Phthalic anhydride synthesis Uranium processing Coal combustion... 

Particle coating Maleic anhydride synthesis Pyrolysis of oil shale Fluidized catalytic cracking... 

A problem that must be carefully considered is the occurrence of side- and consecutive reactions. This is especially important for alkane activation, because severe reaction conditions are necessary to activate the C-H bonds. When reactions are fast, as in the HCN and acetylene syntheses, rapid quenching of the reaction products is possible. Another way of affecting selectivity is to limit the partial pressure of reactants, thus also reducing the partial pressure of the desired product. In this way in the maleic anhydride synthesis conversion is limited by diluting the gas and limiting the amount of oxygen available for the reaction. 

As described above, butylene is employed as part of the feedstock in maleic anhydride synthesis (Table 3, entry 27). Process conditions are similar but, because of the pricing of feedstocks, butane oxidation is mainly employed. 

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. 

The classical phthalic anhydride synthesis is not useful for the synthesis of islandicin. Thus both the benzoylbenzoic acids 9 and 10 on cyclization give exclusively the same anthraquinone 11. 

Catalysis of the synthesis of benzoic anhydride and the hydrolysis of benzoyl chloride, diphenyl phosphorochloridate (DPPC), and benzoic isobutyric anhydride in dichloromethane-water suspensions by water-insoluble silanes and siloxanes, 3- and 4-trimethylsilylpyridine 1-oxide (3b and 3c, respectively), 1,3-bis(l-oxypyridin-3-yl)-l,1,3,3-tetramethyldisiloxane (4), and poly[methyl(l-oxypyridin-3-yl)-siloxane] (5) was compared with catalysis in the same systems by water-soluble pyridine 1-oxide (3a) and poly(4-vinylpyridine 1-oxide) (6). All catalysts were effective for anhydride synthesis and promoted the disproportionation of benzoic isobutyric anhydride. Hydrolysis of benzoyl chloride gave benzoic anhydride in high yield ( 80%) for all catalysts except 3a, which gave mixtures of anhydride (52%) and benzoic acid (39%). The order of catalytic activity for DPPC hydrolysis was 5 > 4 > 3b > 3a > 3c > 6. The results suggest that hydrophobic binding between catalyst and lipophilic substrate plays an important role in these processes. 

In this chapter, we describe results from a series of experiments in which phase-transfer catalysts bearing the 1-oxypyridinyl group were used in a variety of transacylation reactions. These reactions include acid anhydride synthesis, as well as hydrolysis of a mixed anhydride and two acyl chlorides. The reactions were carried out in vigorously stirred suspensions of dichloromethane and water. Particular attention was directed to molecular size (monomeric, dimeric, and oligomeric species), structural characteristics (vinyl versus siloxane chain), and solubility (water versus dichloromethane) of the catalysts. 

Anhydride Synthesis. A wide variety of pyridine 1-oxides are highly selective catalysts for the conversion of acid chlorides and sodium carbox-... 

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