McMurray reactions

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. ... 

Sodium has been dispersed on the surface of alumina, sodium chloride, or titanium dioxide by stirring with excess support at 180-190°C under argon. The first was the most effective for reducing titanium(III) chloride for the McMurray reaction 5.1, being better than the commonly used reduction with zinc.17... 

JA7582>. The reductive coupling of (3) by the McMurray reaction gave the substituted phosphepin (4) as a distillable oil that crystallized in 8-10% yield after purification by HPLC <84AG(E)894>. 

Our second attempt at using the microwave to accelerate reaction rates was on a library of indoles generated by a McMurray coupling reaction. Heating the reaction mixture at 80°C for 8 h produced poor yields of the desired product (entry 1, Table 8.3). However, when the microwave was utilized the isolated yield was raised to 79% and the reaction was completed in only 5 min. This reaction acceleration allowed for the production of a 300-membered library, which produced compounds of high quality in a significantly reduced time. 

McMurray [151] has described the acid-assisted cleavage of the N]-C4 bond in trans 4-hydroxyphenyl p-lactams. The ring opening reaction may proceed with concomitant reduction or formation of carbon-carbon coupling products, as a function of the reagent employed. For instance, Scheme 60, treatment of 196 with 4 equivalents of triethylsilane in neat trifluoroacetic acid led to compound 197. On the contrary, treatment with anisole in trifluoroacetic acid led to compound 198. Unfortunately, no data are provided by authors regarding process yield or final diastereomeric ratio. 

Initially, PPV was synthesized by condensation reactions that can be found in most introductory organic textbooks. Most commonly, reactions such as the Wittig, Knoevenagel, Wurtz-Wittig, or McMurray, as well various dehydrohalo-genation reactions, were employed that yielded oligomers or low molecular weight PPV. 

The conditions using 2,4,6-collidine/Tf20 and having the reaction warm from -78 °C to 25 °C were chosen mainly to avoid using more expensive reagents such as 2,6-di-r-butyl-4-methylpyridine or A-phenyl triflimide. (a) Stang, P. J. Hanack, M. C. Subramanian, L. R. Synthesis 1982, 85. (b) McMurray, J. E. Scott, W. J. Tetrahedron Lett. 1983,24,979. 

Reaction with mercurated nitrophenols McMurray and Trentham (1969) and Stefanini et al. (1972) have described the synthesis of several mercurated nitrophenols (Table 3.2). The spectra of these organomercurials show large changes in the visible region when thiols displace more weakly bound ligands from... 

The plasmalogenic diglyceride, prepared enzymically by the action of phospholipase C on the choline-containing phospholipid of beef heart, is defined as a D-a,/5-diglyceride in which the ester at the cx -position is replaced by an imsaturated ether. The reaction is catalysed by a choline-phosphotransferase enzyme similar to the phosphorylcholine-glyceride transferase shown to participate in the biosynthesis of lecithin (Reaction 12). A similar reaction occurs in brain (McMurray 1964b). 

This reaction is analogous to that previously described for the biosynthesis of choline plasmalogen (Reaction 17). It also occurs in brain tissue (McMurray 1964b). 

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