MacDonald condensation

All of the non-natural isomers (porphycenes) of the porphyrin ring system comprising permutations of four pyrrole rings, four methines and having an 18 Jt-electron main conjugation pathway, have been synthesised. The scheme below shows the use of a MacDonald condensation to assemble a tetrapyrrole and then the use of the McMurray reaction to construct the macrocycle. ... 

Hofmann N, Hilscher B (1991) Use of aniline blue to assess chromatin condensation in morphologically normal spermatozoa in normal and infertile men. Hum Reprod 6 979-982 Howman EV, Fowler KJ, Newson AJ, Redward S, MacDonald AC, Kalitsis P, Choo KH (2000) Early disruption of centromeric chromatin organization in centromere protein A (Cenpa) null mice. Proc Natl Acad Sci U S A 97 1148-1153... 

Clarification by removal of casein with such agents as calcium chloride, acetic acid, cooper sulfate, or rennin has often been employed to obtain a serum more suitable for refractometric measurements. Obviously the composition, and hence the refractive index, of such sera will depend on the method of preparation. Furthermore, some of the serum proteins may be precipitated with the casein by some of the agents used, particularly if the milk has been heated. Refractive index measurements of such sera are not generally considered as satisfactory as freezing point measurements for detection of added water (David and MacDonald 1953 Munchberg and Narbutas 1937 Schuler 1938 Tell-mann 1933 Vleeschauwer and Waeyenberge 1941). Menefee and Overman (1939) reported a close relation between total solids in evaporated and condensed products and the refractive index of serum prepared therefrom by the copper sulfate method. Of course, a different proportionality constant would hold for each type of product. 

Scheme 3 "2+2" Condensation of dipyrromethanes by the MacDonald method and "3+1" synthesis of etioporphyrins.

Sessler and coworkers have synthesized [22]pentaphyrin(2.1.0.0.1) 151 (Scheme 61) by condensing terpyrrole 146 with an alkyne bridged bipyrrole 149 under MacDonald conditions giving rise to a 22jt aromatic macrocycle dehydropentaphyrin 150, which upon treatment with a poisoned Lindlar catalyst (Pd/CaC03) gave 151 (1995TL4713). 

Other examples of such mixed potential models include that developed by Macdonald and Urquidi-Macdonald to predict water radiolysis effects in thin condensed water layers on metal surfaces (24), and the models of Marsh and Taylor (25), and Kolar and King (22) to predict the corrosion of carbon steel and copper waste containers surrounded by a low permeability material such as clay. 

The synthesis of this expanded porphyrin was successfully achieved using [66] a 2 + 3 MacDonald coupling similar to the one used to obtain sapphyrin [26, 66] and pentaphyrin [182, 183]. In this case, a diformyl bipyrrole 194 and a pyrrolyldipyrromethane dicarboxylic acid 225 were condensed in the prince of HBr to give the new macrocycle 226 (Scheme 39) [67]. Here, the requisite pyrrolydipyrromethanes were generated by HBr catalyzed condensations of... 

With the original reports of the successM synthe of the sapphyrins [26,66,152] and uranyl superphthalocyanine [112, 118, 119], interest in other expanded porphyrin systems, was kindled. The next logical step (after sapphyrin), in the expanding series of all-pyrrole systems, was the pentaphyrin macrocycle 231 which contains five pyrroles and five meso-like methine bridgra. In 1983 Gossauer et al. reported the synthesis of the first prototypical member 231 of this macrocyclic family [158, 182, 183, 185-187]. This first synthesis was achieved by a 2 + 3 MacDonald-type condensation between an oc-firee dipyrromethane 233 and a tripyrrane dialdehyde 236. More recently, the synthesis of pentaphyrin 231 has l n achieve by using a dipyrromethane 5,5 -dicarboxylic acid 235 in place of an a-firee dipyrromethane [21]. Here, as is the case in many of these kind of reactions [21,26,27,66,155], decarboxylation occurs under the reaction conditions to produce the corresponding a-free species 233 in situ. (Scheme 40) [21]. 

A.E. DePristo and J.D. Kress, J. Chem. Phys. 1987, 86, 1425. S.H. Vosko and L.D. MacDonald, in Proceedings of the 1986 International Workshop on Condensed Matter Theories, Argonne National Laboratory, edited by P. Vashishta et al. Plenum, New York, 1987. 

The first synthesis of pentaphyrin was reported by Gossauer in 1983. He used an HBr-catalyzed 2 + 3 MacDonald-type condensation between the diformyl tripyrrane 6.29 and the a-free dipyrrylmethane derivative 6.32 to establish the basic macrocyclic framework. Oxidation with chloranil then gave pentaphyrin 6.35 in 31% overall yield (Scheme 6.4.1). Subsequent to this original disclosure, syntheses of pentaphyrins with various other peripheral substituents appeared in the literature (e.g., 6.38 and 6.39). They were all made using this same general procedure." Interestingly, it was found that pentaphyrins could not be prepared when the nucleophilic and electrophilic nature of the reactant dipyrrylmethane and tripyrrane (the 2 and 3 components, respectively) were reversed. This became evident when the diacid tripyrrane 6.38 and the diformyl dipyrrylmethane 6.39 were reacted under conditions identical to those used to prepare pentaphyrin 6.35. Here, only porphyrins, and not pentaphyrins, were obtained (Scheme 6.4.2). " ... 

The synthesis of rubyrin 7.25 involves an acid-catalyzed 4 + 2 MacDonald-type condensation between the diformyl bipyrrole 7.21 and the diacid tetrapyrrane 7.23 (Scheme 7.2.1). After oxidation and purification, a roughly 20% yield of a blue crystalline solid is obtained, which, on the basis of solution-phase spectroscopic and solid-state structural studies vide infra), was assigned the hexapyrrolic structure 7.25. Using a similar procedure, rubyrins 7.26 and 7.27 were also prepared. While the first of these (like 7.25) proved stable, rubyrin 7.27 was found to decompose during chromatographic purification. It was thus characterized only by UV-vis spectroscopy and mass spectrometry. ... 

The lower-carbon, phosphorylated sugars, so important in biochemical processes, also came in for the further attention of Fischer and Ballou. New methods of synthesis were worked out for 2-0-phospho-o-glyceric acid, D-glyceraldehyde 3-phosphate, dihydroxyacetone phosphate, and (with Dr. MacDonald) the enantiomorphous erythrose 4-phosphates. The suspected biochemical importance of the n-erythrose 4-phosphate was then quickly established when Srinivasan, Katagiri, and Sprinson of Columbia University demonstrated its condensation with 0-phospho-enolpyruvic acid to 5-dehydroshikimic acid by Escherichia coli. 

Crouch, S. R., in J. S. Mattson, H. B. Mark, Jr., and H. C. MacDonald, Jr., eds.. Computers in Chemistry and Instrumentation, vol. 3, chap. 3. New York Marcel Dekker, 1972. The sections on the mathematical basis of kinetic methods were condensed from this chapter. It is an excellent source for instrumental and computerization consideration in rate measurement. 

The inverted porphyrins (also called N-confused porphyrins) 289 were discovered accidentally as by-products of the well-known acid-catalyzed pyrrole aldehyde cyclocondensation route to porphyrins (Scheme 58) (see Chapter 14 by Latos-Grazynski). Rational multistep synthetic approaches to inverted porphyrins have t peared recently. Dolphin and coworkers. s have reported a method for the preparation of porphyrin 292 involving acid-catalyzed MacDonald-type (2 -I- 2) condensation of an a,j8-dipyrromethane 291 and a,a-dipyrromethane dialdehyde 290. Lee and coworkers have reported a (3 -I- 1) approach to porphyrin analogues with an inverted pyrrole and a thiphene, or a furan ring system 293 (Scheme 59). Pandey et reported the preparation of dibromo-a, c-... 

A method of degradation with excellent preparative possibilities has been devised by MacDonald and Fischer (200), The higher-carbon sugar first is condensed with ethyl mercaptan to form the bis(ethylthio)acetal (mercaptal) (I) (Chapter IV). Oxidation of the mercaptal with perpro-pionic acid then leads to the bis(ethylsulfonyl) compound (II), which is smoothly degraded by aqueous ammonia to the next lower aldose and bis(ethylsulfonyl)methane. 

The investigation of MacDonald (1963) imphcates glycerol, some carbohydrates, and quinic and shikimic acids, which are known to be derived from carbohydrates, as likely precursors of pyocyanine. This study would make it seem unlikely that pyocyanine is derived primarily from amino acids or from the condensation of acetate and malonate units. However, it was not shown that the ring of quinic acid or shikimic acid is incorporated as an intact unit into the ring structure of pyocyanine, and the suggestion that the ring of pyocyanine was ultimately derived from the ring carbon atoms of two molecules of shikimic acid requires further proof. 

In contrast to this proposal, MacDonald et al. [64] su ested that the chain propagation of polymerization was a slow step, while Gross et al. [65] found that the monomer conversion followed first- order law and was independent of both the type (water, butanol and butyl amine) and concentration of the nucleophile. Yet another group suggested a complex mechanism of polymerization involving ring-opening and linear condensation polymerization [66]. 

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