Anhydrides general structure

Poly(amide-imide) is the condensation polymer of 1,2,4-benzenetricarboxylic anhydride and various aromatic diamines and has the general structure ... 

The mesoionic compounds are represented by structures that cannot be properly described by Lewis forms not involving charge separation. Typical examples are the sydnones 80 the first example was obtained at the University of Sydney by the action of acetic anhydride on N-nitrosophenylglycine [75]. They were consequently named after the Australian town [76]. These structures are best approximated as resonance hybrids. They can be represented by any contributing mesomeric structure a, b, c or by the general structure d. 

Indicator dyes for pH having the phthalide structure fall into two types, the phthaleins, shown in the lactone form of general structure (1.66) and the sulfoph-thaleins (1.67). The synthetic pathways to these products are very similar. The phthaleins (1.66) are made by reacting phenol with phthalic anhydride in the presence of Lewis acid catalyst, e.g. ZnCl, whilst (1.67) are obtained by using 2-sul-fobenzoic anhydride (Figure 1.20). 

Compds of the general structure RC(0)N(N02)A.CH2.C(N02)2CH2.Ar N(N02)-C(0)R where R is alkyl and A is alkalene, were also patented by Frankel Sc Klager (Ref 4) for use as HE chges or proplnt additives. These nitramides are prepd by heating the appropriate dinitrodi-amines with acyl anhydrides and treating the product with HNO - Thus, the following N-nitro nitramides were prepd cited ... 

An example of 2,4,6-triphenylpyrylium-3-olate (65 R = R = R = Ph, R = H) reacting as a 1,3-dipole was first provided by Suld and Price who obtained a maleic anhydride adduct (C25HigO5). Subsequently, an extensive study of the cycloadditions of this species has been published by Potts, Elliott, and Sorm. With acetylenic dipolarophiles, compound 65 (R = R = R = Ph, R = H) gives 1 1 adducts that have the general structure 74 and that isomerize to 6-benzoyl-2,4-cyclohexadienones (76) upon thermolysis. This thermal rearrangement (74 -> 76) has been interpreted in terms of an intermediate ketene 75. The 2,3-double bond of adduct 74 (R = Ph) is reduced by catalytic hydrogenation. Potential synthetic value of these cycloadducts (74) is demonstrated by the conversion of compound 74 (R = Ph) to l,2,3,4,6-pentaphenylcyclohepta-I,3,5-triene (79 R= Ph) via the alcohol 78 (Scheme 1). ... 

Anhydride (Section 22.1) A compound having the general structure (RC0)20. 

Carboxylic acid derivatives (Section 20.1) Compounds having the general structure RCOZ, which can be synthesized from carboxylic acids. Common carboxylic acid derivatives include acid chlorides, anhydrides, esters, and amides. 

Preparation of starch succinate or alkenylsuccinates by reaction with succinic anhydride or its derivatives. The general structure of these compounds is... 

Figure 5 General structure of poly anhydrides. R and R can be varied to modify degradation kinetics and profile. The lower frame shows the structure of P(CPP-SA), a poly anhydride copolymer, used in the Gliadel product. Abbreviations SA, sebacic acid CPP, carboxyphen-oxypropane.

Two carboxylic acid groups may combine to form an acid anhydride with the general structure shown in Figure 9-7. We discuss this combination in more detail, including synthesis and reactions, in Chapter 12. 

Using micro-Raman imaging three blends consisting of polypropene/polyethene/ethene-propene copolymer, PBTP/polycarbonate/LDPE, and styrene-acrylonitrile copolymer/styrene-maleic anhydride copolymer/ polydimethylphenylene oxide were studied with regard to compositional and morphological heterogeneities. The general structure of PE fibres in an epoxy resin matrix was also studied. 59 refs. 

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