Cyclic anhydride treatments

Cyclic anhydrides do not yield a by-product when reacting with the hydroxyl groups of fiber. The anhydride covalently bonded on wood by an ester function yields a free carboxylic group at its end. The free carboxylic group can in theory react with another OH group to crosslink the cell walls polymers of wood [41]. 

Cyclic anhydrides have been studied as chemical reagents for wood modification phtalic anhydride, maleic anhydride, glutaric anhydride, succinic anhydride and alkenyl succinic anhydrides (ASA) [42]. Scots pine-treated samples with petrochemical octenyl succinic anhydrides (ASAs) dissolved in pyridine that after treatment did not present enough resistance against fungi decay but increased dimensional stability. 

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Pyrrole is one of the most prominent heterocycles, having been known for more than 150 years, and it is the structural skeleton of several natural products, synthetic pharmaceuticals, and electrically conducting materials. A simple access to the pyrrole ring system involves the conversion of cyclic anhydrides into five-membered imides. Mortoni and coworkers have described the conversion of 2-methylquinoline-3,4-dicarboxylic acid anhydride to a quinoline-3,4-dicarboximide library by treatment of the anhydride with a diverse set of primary amines under microwave conditions (Scheme 6.180) [341]. The authors studied a range of different conditions, including dry media protocols (see Section 4.1) whereby the starting materials were adsorbed onto an inorganic support and then irradiated with microwaves. For the transforma-... 

Reactions of titanocene-methylidene generated from titanacyclobutanes with acyl chlorides 55 [46] or acid anhydrides 56 [47] lead initially to the titanium enolates 57 (Scheme 14.24), which then afford aldols upon treatment with the carbonyl compounds. On the other hand, five-membered cyclic anhydrides are methylenated with dimethyltitanocene (Table 14.5, entry 7) [45]. 

In a similar manner to the preparation of 1,3,2-dioxathiolane 2-oxide from 1,2-dihydroxyethane and thionyl chloride, 1,2,3-oxadithiolane 2-oxide was prepared from 2-mercaptoethanol and thionyl choride <75ACS(A)414>. 1,2,5-Oxadithiolane 2,5-dioxide (66), the cyclic anhydride of ethane-1,2-disulfinic acid, was obtained by controlled hydrolysis of ethanebis(disulfinyl) chloride <76CRV747>. The corresponding 2,2,5,5-tetroxide (67) was obtained by treatment of ethane-1,2-disulfonic acid with thionyl chloride <(66HC(2l-i)l>. 

Reaction of phthalic anhydride (70-1) with the ylide from ethyl triphenylphos-phoniumacetate leads to the condensation product (70-2), which in effect consists of a cyclic enol anhydride. Treatment of this product with hydrazine leads to the hydrazone-hydrazide (70-3). Alkylation of the anion from removal of the hydrazide proton with the substituted benzyl bromide (70-4) affords the alkylation product (70-5). Saponification then leads to the aldose reductase inhibitor ponalrestat (70-6) [79]. 

The known adduct (385) of furan and vinylene carbonate, previously used for the synthesis of some cyclitols,256,257 has been transformed into DL-ribose derivatives. After hydroxylation of 385 and subsequent formation of the isopropylidene derivative, the carbonate group was removed by treatment with barium hydroxide, and the resulting diol was cleaved by oxidation with permanganate. Dicarboxyl-ic acid 386 gave, upon treatment with acetic anhydride, cyclic anhydride 387. The reaction of 387 with azidotrimethylsilane produced... 

Just as homoannular ferroeenedicarboxylic acid leads to a cyclic anhydride (23), so does the heteroannular ferroeenedicarboxylic acid. Thus treatment of the dichloride of ferrocene-l,l -dicarboxylic acid with water in chloroform-pyridine gave the anhydride (34).21 Treatment of 34 with ammonium hydroxide led to ring opening and formation of the diamide and the monoamide-monoacid.21... 

The present treatment of post-1978 literature is divided according to the nature of the heterocyclic substrate (monocyclic, bicyclic, tricyclic, or spiro) each of these broad categories is then subdivided alphabetically, with reduced substrates included with their aromatic counterparts. Cyclic anhydrides, cyclic imides, lactones, and the like are classified as the appropriate heterocyclic derivatives. A glance index to the main product types is appended as Section 2.5. 

Curing of epoxy resins by polycarboxylic acids and cyclic anhydrides is also important in applications, but it is much less understood due to more complex reaction mechanism. Also, the statistical treatment is less developed and partly requires a revision. In this section, the statistics of curing of epoxy resins with polycarboxylic acids and cyclic anhydrides is discussed. 

Sn[N(TMS)2l2, A, A -carbonyldiimidazole (110, p. 1418), which behaves as in reaction 16-63, POCl3, °" TiCl4, ° molecular sieves,Lawesson s reagent (p. 1278), ° and (MeO)2POCl. ° Certain dicarboxylic acids form amides simply on treatment with primary aromatic amines. In these cases, the cyclic anhydride is an intermediate and is the species actually attacked by the amine. Carboxylic acids can also be converted to amides by heating with amides of carboxylic acids (exchange),sulfonic acids, or phosphoric acids, for example, ... 

The cyclic anhydride was converted into the amide acid which on Hofmann rearrangement followed by lithium borohydride reduction on the ester gave a derivative of ip-amino-2a, 3a-dihydroxy-43-hydroxy-methylcyclopentane. Condensation of the amino-triol with 5-amino-4,6-dichloropyrimidine followed by ring closure with triethyl orthoformate gave the 6-chloropurine derivative which on treatment with ammonia gave 11. ... 

Hie cyclic anhydride (80.4) reacts with trimethylsilyi azide under anhydrous conditions to give a mixture of I,3-oxazine-2,6-dione isomers, which was used without further purification to synthesis several extended purines. Reaction with formamidine acetate in DMF in effect replaced the furandione ring by a pyrimidinone. Cyanamide produced a new fiued 2-aminopyrimidin-4-one [in (80.5, R = NH )], while urea led to a pyrimidinedione. Isatoic anhydride similarly yields 2-aminoquinazolin-4-one on treatment with cyanamide-DMF. 

Permanent-press fabrics are often cured with TV-methy-lol compounds, such as 4.18, and tend to release formaldehyde after the cure. (Formaldehyde [a carcinogen] from various formaldehyde resins is a problem in some homes.115) These can be replaced with polycarboxylic acids, such as the 1,2,3,4-butanetetracarboxylic acid (4.19), which cure via the cyclic anhydride.116 Both dyeing and durable-press treatments can be combined in a single step, if desired.117... 

In the case of the reduced derivative of cholesterol, 5-1 (Scheme 1.5), the initial oxidation goes to the highly substimted adipic acid 5-2. The observation that this leads to a cyclopentanone (5-3) can be inferred to indicate that the ring at the start of the scheme was six-membered. Further oxidation of the cyclopentanone again leads to a dicarboxylic acid. On treatment with acetic anhydride, that intermediate leads to a cyclic anhydride. This leads to the inference that the precursor 5-3 was a cyclopentanone. 

Hydrolysis of the ester functions of dimethyl 2,2-bis(4-methoxyphenyl)-277-naphtho[l,2-6]pyran-5,6-dicarboxylate and cyclisation of the resulting dicarboxylic acid yields the cyclic anhydride 51. Reduction affords a mixture of two isomeric furano-fused naphthopyrans. Treatment of the anhydride with primary amines provides a route to the corresponding pyrrole derivatives. Both types of hetero-fused naphthopyrans show a red shift relative to the starting naphthopyran diester and reduced half-lives <01 WOP32661>. 

Chiral y-amino-acids (e.g. 180) have been prepared from the corresponding optically active /8-amino-acids by the addition of one carbon atom using the Arndt-Eistert reaction.w-Amino-acids are available from cyclic anhydrides by treatment with stannyl azide (to give an w-isocyanatocarboxylic acid) followed by addition of an alcohol. In contrast to simple enamines, oxidation of N-acyl-a-aminocrotonates with thallium nitrate leads to the corresponding a/8-dimethoxy derivatives. 

Tin.—Allyltin compounds, especially under rhodium-complex catalysis, react with acyl chlorides to give allyl ketones or with aryl halides to give allylarenes. Bridgehead alkyl bromides are reduced on photolysis with Bu"3SnH, whilst the system (Bu"3Sn)20-Br2 oxidizes sulphides to sulphoxides. )V-(Alkoxycar-bonyl)amino-acids are obtained upon treatment of cyclic anhydrides with Bu3SnN3 and heating in an alcohol. ... 

As shown in Table 3.2, 5% BTCA in the presence of 10% SHP and 0.1% TiO (as a cocatalyst) was nsed, and the addition of TiO as a cocatalyst further increased WRA by 58.5%. This was becanse both TiO and SHP accelerated the catalytic reaction throngh the formation of ester bonds between the cyclic anhydride ring and the hydroxyl gronp of cellulose. The improvement of WRA by the addition of TiO in the BTCA treatment was probably dne to the nniqne photocatalytic properties of TiO, which is a kind of N-type semicondnctor. The hydroxyl radical (-OH) and snperoxide anion (-0 -) formed may have acted as catalysts to accelerate the formation of anhydrides from poly (carboxylic) acids. Fnrthermore, the effect of hydroxyl radical (-OH) and superoxide anion (-O -) on the increase of charge localization of the sohd cellulose medium in which esterfication and cross linking occur may also have been significant. Therefore, WRAs of cotton fiber treated with 5% BTCA, 10% SHP, and 0.2% TiO further increased to 61.3% compared with those of the untreated cotton fabric. The increment was proportional to the increase of TiOj from 0.1 to 0.2% in the BTCA treatment bath (Lam et al., 2011). 

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