From cyclic anhydrides

Lipase-catalyzed synthesis of polyesters from cyclic anhydrides and oxi-ranes was reported. The polymerization took place by PPL catalyst and the molecular weight reached 1 x 10" under the selected reaction conditions. During the polymerizahon, the enzymatically formed acid group from the anhydride may open the oxirane ring to give a glycol, which is then reacted with the anhydride or acid by lipase catalysis, yielding the polyesters. 

Complex amine formation from cyclic anhydride and aromatic amine formation of triaryl phosphine Sterling Organics Amery et al. (1994)... 

Spirolactones may also be prepared from cyclic anhydrides by the action of 1,5-bis(bromomagnesio)pentane (8lJOC309l>. The reaction proceeds through the keto acid... 

Important method for preparation of cyclic imides from cyclic anhydrides. 

If a chain has different ends and the same type of ends cannot be on both ends of one chain (e.g. two initiator molecules or two living ends), this fact must be respected in the cascade generation. Therefore, the bond directions are specified with respect to the type of chain end (cf. also Ref. ). For example, for linear chains formed from cyclic anhydride and monoepoxide (Fig. 18) one can formally place the bound molecule of the initiator in the left branch and denote this direction by 1 and the direction to the living end in the right branch by r. 

Another sequence of that type starts from cyclic anhydrides of dicarboxylic acids which on reaction with a set of nucleophiles, e.g., amines, open under liberation of a free carbox-ylate. These products can then be coupled with a further set of nucleophiles (Scheme 3.7, see [13-15,21]). 

Macrocyclic diesters. Very high template abibty of the reagent enables the efficient synthesis of the diesters from cyclic anhydrides and glycols in one step. 

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. 

Although the carbonylation reactions of nickelacycles prepared from cyclic anhydrides is of no synthetic interest, the corresponding reactions of metallacycles synthesized from unsaturated carboxylic acids or alke-... 

Acyclic acid anhydrides react with alcohols (phenols) to give esters and carboxylic acids acid esters (monoesters) are formed from cyclic anhydrides ... 

P. Canonne and D. Belanger, /. Chem. Soc., Chem. Commun., 1980, 125. Spirolactones from cyclic anhydrides and BrMg(CH2)4MgBr. 

Sabitha and coworkers have introduced a rapid and high yielding procedure for the preparation of half-esters (160) from cyclic anhydrides using the requisite alcohol and Bp3 OEt2 (Equation 95) [97]. Compared to the other Lewis acids attempted, the reaction with Bp3 OEt2 is spontaneous and clean, and requires only a simple work-up. 

In this category a collection of some unsorted methods for the synthesis of 8-lactones are described. Canonne et al. have reported a one-step spiroannelation for the synthesis of spiro-8-lactones from cyclic anhydrides [117]. Addition of 1,4-bis(bromo-magnesio)butane to spirocyclic anhydride 312 led to intermediate 314 via the formation of 313, and subsequent treatment with HCl provided spiro-8-lactone 315 (Scheme 69). The scope of this method was further demonstrated with several anhydrides to synthesize a variety of spiro-8-lactones. 

The acylation of enamines derived from cyclic ketones, which can lead to the acyl ketone or ring expansion (692-694), was studied by NMR and mass spectroscopic analysis of the products (695,696). In a comparative study of the rates of diphenylketene addition to olefins, a pronounced activation was observed in enamines (697). Enamine N- and C-acylation products were obtained from reactions of Schiff s bases (698), vinylogous urethanes (699), cyanamides (699), amides (670,700), and 2-benzylidene-3-methylbenzothiazoline (672) with acid chlorides, anhydrides, and dithio-esters (699). 

Cyclic 1,3-diacetoxy-l,3-dienes can be generated in situ from cyclic 1,3-diketones under the influence of isopropenyl acetate. The dienes then undergo Diels-Alder reactions with maleic anhydride giving as products 1-acetoxybicycloalkane dicarboxylic anhydride derivatives (10). The procedure is also successful with cyclic 1,2- and 1,4-diketones as well as cyclic a,j3-unsaturated ketones. The products, after hydrolysis to... 

What product would you expect from reaction of 1 equivalent of methanol with a cyclic anhydride, such as phthalic anhydride 0,2-benzenedicarboxylic anhydride) What is the fate of the second "half" of the anhydride ... 

Cyclic acid anhydrides are highly reactive not only to electrophilic attack but also to nucleophilic attack. Alternating copolyesters were obtained from cyclic acid anhydrides and epoxides at high temperatures261-263. ... 

The principles set forth above account reasonably well for the course of bifunctional condensations under ordinary conditions and for the relative difficulty of ring formation with units of less than five or more than seven members. They do not explain the formation of cyclic monomers from five-atom units to the total exclusion of linear polymers. Thus 7-hydroxy acids condense exclusively to lactones such as I, 7-amino acids give the lactams II, succinic acid yields the cyclic anhydride III, and ethylene carbonate and ethylene formal occur only in the cyclic forms IV and V. 

Nitration of the potassium enolates of cycloalkanones with pentyl nitrate81 or nitration of silyl enol ethers with nitronium tetrafluoroborate82 provides a method for the preparation of cyclic a-nitro ketones. Trifluoroacetyl nitrate generated from trifluoroacetic anhydride and ammonium nitrate is a mild and effective nitrating reagent for enol acetates (Eq. 2.41).83... 

Accelerations (or decelerations) imposed by the cycloamyloses on the rate of an intramolecular reaction may be derived from a conformational effect. The rate of an intramolecular reaction depends not only on the proximity of the reactive groups but also on their relative orientation. For example, Bruice and Bradbury (1965) have shown that the rates of formation of cyclic anhydrides from mono esters of 3-substituted glutaric acids depend on the size of the substituent at the 3-position. This observation was interpreted as a change in the ground state population of reactive and non-reactive conformers as the 3-substituents are varied (Scheme IX). Reason-... 

Triafulvenes derived from cyclic 0-dicarbonyl systems like 84/85ia 861S and S779 are conveniently prepared from cation 75 by the DIPEA method and in some cases (5780,81), 8862 8983 ) from diphenyl cyclopropenone by condensation in acetic anhydride. 

The double bond of maleic anhydride may undergo free radical polymerization with the proper initiator. Polymers of maleic anhydride (or copolymers made with another monomer) are commercially available (Polysciences). They consist of a linear hydrocarbon backbone (formed from the polymerization of the vinyl groups) with cyclic anhydrides repeating along the chain. Such polymers are highly reactive toward amine-containing molecules. 

Maleic acid is a linear four carbon molecule with carboxylate groups on both ends and a double bond between the central carbon atoms. The anhydride of maleic acid is a cyclic molecule containing five atoms. Although the reactivity of maleic anhydride is similar to other cyclic anhydrides, the products of maleylation are much more unstable toward hydrolysis, and the site of unsaturation lends itself to additional side reactions. Acylation products of amino groups with maleic anhydride are stable at neutral pH and above, but they readily hydrolyze at acid pH values around pH 3.5 (Butler et al., 1967). Maleylation of sulfhydryls and the phe-nolate of tyrosine are even more sensitive to hydrolysis. Thus, maleic anhydride is an excellent reversible blocker of amino groups to temporarily mask them from reactivity while another... 

The photolysis of carboxylic acids and derivatives as lactones, esters and anhydrides can yield decarboxylated products 253>. This reaction has been utilized in the synthesis of a-lactones from cyclic diacyl peroxides 254) (2.34) and in the synthesis of [2,2]paracyclophane by bis-decarboxylation of a lactone precursor (2.35) 255). This latter product was also obtained by photoinduced desulfurization of the analogous cyclic sulfide in the presence of triethyl phosphite 256). 

Quinazolines, the benzo derivatives of pyrimidines, were prepared in a variety of ways, from methods analogous to those for synthesizing pyrimidines to vastly different condensation schemes. In analogous fashion to many pyrimidine preparations, Yang and coworkers reported the condensation of polymer-tethered amidines 109 with cyclic anhydrides 110 to yield a library of 2-amino-4(3//)-quinazoIinones 111 after cleavage from the resin <00TL7005>. 

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