Ester-containing macrocycles

Macrocyclic amides and esters containing the 2,6-dipicolinate subunit. . 241... 

Table 5.11. Macrocyclic esters containing the 3,5-dipicolinate subunit...

As for the biaryl ether containing macrocycles, an array of bioactive macrocycles with an endo aryl-aryl bond exist in nature. A new palladium catalyzed reaction has been recently developed in which bis(pinacolato)diborane(4) mediated the process to reach such a structural motif. The reaction consists of a domino process involving a Miyaura s arylboronic ester synthesis and an intramolecular Suzuki-coupling. Synthesis of a bicyclic A-B-O-C ring system of RP-66453 273, a neurotensine receptor antagonist, with an endo aryl-aryl and an endo aryl-aryl ether bond was described (Scheme 53).141... 

MacFocyclic lactone (Section 22.6A) A cyclic ester contained in a large ring. Macrocyclic lactones are also called macrolides. 

A CD-PEI derivative containing macrocyclic metal centers have been prepared by random functionalization (34), Here, the secondary and the tertiary amino groups were blocked by acetylation. Hydrolysis of a nitrophenyl carboxylate ester... 

The pigments of the Fusaria have been described in Chapter 7. Many of the characteristic phytotoxic metabolites are the sesquiterpenoid trichothecenes (8.38) (see Chapter 5). The more highly hydroxylated members have considerable mammalian toxicity as well as phytotoxicity. Trichothecenes have been identified as metabolites of species from ten of the twelve sections of the genus Fusarium as classified by Booth. The trichothecenes occur with various combinations of oxygen substituents at positions 3, 4, 7, 8 and 15. Several trichothecenes contain macrocyclic esters linking C-4 and C-15. These are known as the roridins and verrucarins. 

Another group of phosphorus- and oxygen-containing macrocycles are the cyclic phosphorus esters. For example, Robert developed a series of 12- and 18-membered rings, (8), and Picavet has synthesized the system based on cyclic phosphite esters, (9). French workers have prepared a series of macrocycles, containing two tertiary phosphine groups and two oxygen atoms (Scheme 1). The methylenic chains may be of two or three units. ... 

In fact, one boronic acid can reversibly form a boronate ester with two OH groups (one diol group), and one diboronic acid can immobilize two suitably positioned diol units to form a saccharide-containing macrocycle. Selectivity can be achieved by controlling the relative spatial position of the two boronic acids in relation to the cis-diol moieties on the saccharide. A given monosaccharide possesses at least two binding sites that differ from other monosaccharides. 

Applying a similar protocol to various azido—alkyne-functionalized furanosides possessing ester (142—143), triazole-containing macrocycles (144—145) of various ring sizes were prepared [84]. This strategy has also been utilized for the development of cyclic peptides containing macrocycles used as building blocks for the assembly of oriented nanotubes (Scheme 6.39) [85]. 

It should be stressed that there has been considerable interest in macrocycles containing the pyridine subcyclic unit, especially by Newkome and coworkers (see also Chap. 4). Most of his interest appears to have been focussed on polyethers rather than ester compounds. Bradshaw has also reported syntheses of compounds containing the pyridine subcyclic unit. ... 

Although most of the macrocycles that contain phosphorus or arsenic which have thus far been prepared, are primarily transition metals binders, two compounds have been prepared which are essentially crown ethers containing phosphorus. Kudrya, Shtepanek and Kirsanovhave prepared two compounds which are essentially polyoxygen macrocycles but which contain one or two methylphosphonic acid esters as part of the ring. These two macrocycles are shown below as 7d and 17 and are both prepared by the reaction of 2,2 [oxybis(ethyleneoxy)] bisphenolate with methylphosphonic dichloride in a mixture of acetonitrile and benzene. The crystalline monomer 16) and dimer 17) were isolated in 17% and 11% yields respectively as indicated in Eq. (6.13). 

Chapter 5 Compounds which contain either an ester or an amide link in a single macrocyclic ring. This includes lactones, lactams, carbonates, carbamates, ureas, phosphates, etc. including sulfur, nitrogen and other atoms in the ring. 

The p a values of two systems with two intra-annular COOH groups have been measured. In Cram s study (Bell et al., 1982), the macrocyclic diacid [36] and an open-chain monomeric analogue [37] had almost identical pK values (see Table 18). In contrast, Gennari s compound [38], which contains two intra-annular COOH groups and in addition two"ethyl ester groups, has a different acidity from that of the analogues [39] and [40], as shown in Table 19 (Gennari et al., 1992). But in both systems, the difference Ap a between pK i and p a2 was comparable (ApA a [36] = 1.7, Ap/La[38] = 1.5). The increase from p ai to P a2 may occur for two... 

Table 19 values for a macrocycle containing two carboxylic acid and two carboxylic ester groups [38] and for analogues [39] and [40] in Me0H/H20 (1 1). 

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