Ulmann reaction

The Ulmann reaction of 4-bromo-3-(2-aminophenyl)thiomethyl-3-pyra-zolin-5-ones (74) in a nonpolar solvent such as xylene and in the presence of a small amount of pyridine afforded 1,2,4,10-tetrahydro-3//-pyrazolo[3,4-c][l,5]benzothiazepin-3-ones (75). However, when the same reaction was... 

For the formation of permethrin, the Ulmann-reaction of permethric acid 3-bromobenzyl ester and phenolate is also a proposed alternative [916]. 

The ultrasonic field considerably accelerates processes and increases yields of Al-organic complexes with low-active alkyl halides, complexes of sodium, naphthaline, benzoquinoline, and other aromatic compounds [742], Use of US treatment in Ulmann condensation [742] in the presence of copper powder (3.285) allows acceleration of the reaction rate 50 times and a yield of 81% in comparison with <1.5% without US ... 

Wahl A, Ulmann M, Carroy A, Augustynski J (1994) Highly selective photo-oxidation reactions at nanocrystalline Ti02 film electrodes. J Chem Soc Chem Commun 19 2277-2278... 

Recent renaissance in Ulmann chemistry has opened new opportunities for successful implementation of novel cross-coupling approaches, especially useful for carbon-heteroatom bond formation under mild conditions with copper compounds. Numerous publications have appeared dealing with thiolation and selenation of aryl-and alkenyl halides using various Cu complexes as catalysts. A high reaction temperature of 200-300 °C [55] was significantly reduced, to 100 °C and less. Therefore, a simplified reaction technique and cheaper solvents may be utilized in synthetic procedures. Lower temperature was also of much importance to avoid side reactions. 

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