Lactones, from anhydrides

L-Homoserine (2-amino-4-hydroxybutyric acid) [672-15-1] M 119.1, m 203", [cc]d +18.3" (in 2M HCI), pKEst(i) -2.1, pl st(2) 3. Likely impurities are A -chloroacetyl-L-homoserine, N-chloroacetyl-D-homoserine, L-homoserine, homoserine lactone, homoserine anhydride (formed in strong solns of homoserine if slightly acidic). Cyclises to the lactone in strongly acidic soln. Crystd from water by adding 9 volumes of EtOH. 

Table 26 Compounds T8[(CH2)3NRiR2]8 obtained from the reaction of T8[(CH2)3NH2]8 with lactones and anhydrides...

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). 

Other reagents used for the preparation of lactones from acid anhydrides are lithium borohydride [1019], lithium triethylborohydride (Superhydride ) [1019] and lithium tris sec-butyl)borohydride (L-Selectride ) [1019]. Of the three complex borohydrides the last one is most stereoselective in the reduction of 3-methylphthalic anhydride, 3-methoxyphthalic anhydride, and 1-methoxynaphthalene-2,3-dicarboxylic anhydride. It reduces the less sterically hindered carbonyl group with 85-90% stereoselectivity and is 83-91% yield [1019]. 

In addition to the procedures listed in Table 3.38, further reactions have been used to generate halides upon cleavage. In Section 3.5.2, iodolactonization is presented as a method for the preparation of iodomethyl lactones from resin-bound pentenoic or hexenoic acid derivatives. Closely related to the iodolactonization is the iodine-mediated formation of 2-(iodomethyl)tetrahydrofurans from resin-bound isoxazoli-dines (Entry 9, Table 3.38 for the mechanism, see Figure 15.5). Nitriles can also be prepared by cleavage and simultaneous dehydration of amides RCONH2 from the Rink or Sieber linkers with TFA anhydride (Entry 10, Table 3.38). 

TABLE 4.20 Shift Position of the C—O Group and other Carbon Atoms of Carboxylic Acids. Esters, Lactones, Chlorides Anhydrides, Carbamates, and Nitriles (ppm from TMS)... 

The dihydroxy lactone from L-threonic acid is prepared from L-dibenzoyl tartaric anhydride by catalytic hydrogenation over palladium. The substituted anhydride is formed from tartaric acid and benzoyl chloride. 

A large number of copolymers of cyclic ethers, cyclic sulphides and cyclic formals have been prepared. Many cyclic compounds that will not homopolymerize do copolymerize readily [7, 146,147]. Some cyclic compounds will copolymerize with lactones, cyclic anhydrides, or vinyl monomers. Very many commercially important materials have resulted from these copolymerizations. 

Machrouhi, F., Namy, J.-L. T54, 11111 (1998). For an alternative method for the preparation of such lactones from y-ketoacids or succinic anhydride by reaction with organic halides, see Machrouhi, F., Parlea, E., Namy, J.-L. EJOC 2431 (1998). 

Nucleophilic species derived from treatment of lactones and anhydrides with base can also react with 3,4-dihydroisoquinolines or with 1-chloroquinolines to give quinolizidines. Two examples of the application of this methodology to the preparation of berberine derivatives (272) and (273) <84LA389> are shown in Equations (31) and (32). 

Several quinones have been identified by Soxhlet extraction of atmospheric particulate material, including anthraquinone and more complex multi-ring compounds (Choudhury, 1982 Ramdahl et al., 1982). In addition, more than 40 other oxygenated PAHs including aldehydes, ketones, lactones, and anhydrides have also been characterized from airborne particle extracts (Choudhury, 1982 Newton et al.. 

Zwitterions are spontaneously formed by reaction of nucleophilic monomers such as cyclic exo and endo imino ethers, azetidines, cyclic phosphites, and Schiff bases on the one hand, with electrophilic monomers like lactones, cyclic anhydrides, sulfones, and acrylic compounds on the other hand (Table 22-6), that is, either from two suitable heterocyclic compounds or from a heterocyclic compound and an acrylic compound. According to reaction partners, the reaction already occurs at room temperature or only after heating. 

Pyridine acetic anhydride Alkylidene-a, -ethylene-y-lactones from a,j -acetyleneoxo compds. and carboxylic acids... 

Acetic anhydride pyridine Lactones from hydroxycarboxylic acids... 

A procedure for the direct preparation of /S-lactones from /3-hydroxy-acids has been reported. Treatment of the 17,20-dihydroxy-21-oic acid (39) with acetic anhydride and pyridine gave (40). The route followed was found to be highly dependent on steric factors. 

A reaction analogous with that of cyclic-anhydride-formation is the formation of lactones from 7-hydroxy acids and from 7-halogen acids. (Cf. page 39.) A related reaction is the dehydration of acids possessing a carbonyl group in the gamma position. 

Sulfuric acid/acetic anhydride a,j( -Ethylene- -lactones and lactones from 7-ketocarboxylic acids... 

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. 

Chlorination of alcohols by Thionyl Chloride the preparation of acyl chlorides from lactones and anhydrides, and the bromi-nation and iodination of aromatic rings by Benzyltrimethylammo-nium Tribromide and Benzyltrimethylammonium Dichloroio-date, respectively, are all effectively catalyzed by the presence of ZnCl2. In addition, ZnCl2 acts as a source of chloride for the halogenation of primary, secondary, and allylic alcohols using Triphenylphosphine-DiethylAzodicarboxylate. ... 

A mixture of 10 g of the glyoxylic acid, 100 ml of acetic anhydride, and 0.5 g of 2,4-dinitrobenzenesulfonic acid is stirred at 25° for 2 hr. Sodium acetate (0.5 g) is added and the mixture concentrated in vacuum at 50°. The residue is taken up in 100 ml of benzene and washed with two portions of 2.5 N sodium hydroxide to remove the remaining acetic anhydride. The benzene solution is washed with water, dried and concentrated in vacuum to dryness. Crystallization from 40 ml of absolute ethanol gives 9.8 g (85%) of 3a,20,23-trihydroxy-16a-methyl-11 -oxo-21 -norchola-17(20),22-dienoic acid-24(20)-lactone 3,23-diacetate mp 165-175°. 

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