Selected synthetic procedures

The Ullmann synthesis of symmetrical biaryls Preparation of 2,2 -(timethoxy-4,4 -dimethoxycarbonylbiphenyl (64) [15] 

A mixture of methyl 3-methoxy-4-iodobenzoate (65, 5.00 g, 17 mmol) and activated copper bronze (15.00 g, 236 mmol, 14 eq.) was heated under argon at 210-220 C (internal temperature) for 3 h. The cooled mixture was exhaustively extracted with boiling ethyl acetate and the residue left on removal of the solvent was crystallized from methanol. The 2,2 -dimethoxy, 4 -dimethoxycarbonylbiphenyl (65, 2.58 g, 91%) was isolated in the form of blades, m.p. 163-165 °C. 

The Ullmann homo-coupling reaction of pofyhalogenated substrates Preparation of 3,3 ,5,5 -tetrabromobiphenyl-2,2 -biscarboxaldehyde (14) [14] 

The Ullmann homo-coupling reaction of activated heteroaryl halides Preparation of 2,2 -bipyrimidine (17) [19] 

2-Iodopyrimidine (66, 15.00 g, 72.8 mmol) and activated copper powder (17.50 g, 275 mmol, 3.98 eq.) were placed in a 250 ml double-necked flask fitted with a reflux condenser, a N2 inlet, and a magnetic stirrer. Absolute DMF (60 ml) was added, and the flask was flushed with N2 for 10 min. The reaction mixture was heated to 80 °C with vigorous stirring at the temperature kept between 80 and 85 °C. After 3.5 h, activated copper powder (4.00 g, 63.0 mmol) was added to the mixture, and the N2 inlet was replaced with a calcium chloride tube. After another 3.5 h, the temperature was increased to 120-130 C and the stirring was continued for 2 h. The suspension was then cooled to 0 C, carefully drowned into a solution of potassium cyanide (23.00 g) in 115 ml of 25% aqueous solution of ammonia, and filtered. The solid residue was 

NaOH (2 ml) and stirred at 60 °C for 10 min after which PMe3 (1 M solution in THF, 3.73 ml, 3.73 mmol) was added. The reaction was monitored hy TLC (DCM/MeOH/HjO/MeNHj (33% solution in EtOH), 10 15 6 15 in EtOH, product J f = 0.33), which indicated completion after 3.5 h. The reaction mixture was then purified by flash chromatography on a short sihca column that was eluted as follows THF, EtOAc, MeOH/EtOAc (1 1), MeOH, and finally with MeNHj (33% solution in EtOH). The fractions containing the product were evaporated under vacuum, redissolved in water, and evaporated again to afford the product in its free amine base form (48.7 mg, 81%). This product was then dissolved in water, the pH was adjusted to 7.5 with 0.01 M H2SO4, and lyophihzed to give the sulfate salt of 99 (88.5 mg) as a white foamy sohd. 

We thank the US-Israel Binational Science Foundation (grant no. 2006/301) and the FP7-PEOPLE-2009-RG Marie Curie Action Reintegration Grants (Grant 246673) for their generous support that has made it possible for us to perform our studies in the field of AG antibiotics. 

Baussanne, I., Bussiere, A., Haider, S., Ganem-Elbaz, C., Ouberai, M., 

Rutenberg, R., Kramer, M., Berkov-Zrihen, 

Breiner-Goldstein, E., Garneau-Tsodikova, S., and Fridman, M. (2011) Org. Biomol. Chem., 9, 4057-4063. 

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Two years have passed since this series reviewed a year s (1967) progress in the chemistry of nucleosides and nucleotides. During this time there has been no decline in interest and activity in this field the enormous number of organic chemical publications parallels the intense activity of biochemists and biologists in nucleic acid research. This review surveys chemical work published during 1968 and 1969, with particular emphasis on synthetic aspects. The first volume of a very useful series of selected synthetic procedures in nucleic acid chemistry was published during this period. 

In conclusion, the use of POM catalysts, along with beiugn oxidants represents a true possibihty for the development of novel and selective synthetic procedures. In this scenario, water splitting for energy applications represents a challenging frontier in TMSP-based catalysis, nowadays attracting great attention. 

A variety of economical, efficient, and selective synthetic procedures have been developed for the synthesis of fxmctionalized indole rings [5,6]. They can be divided in two categories ... 

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