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Atrstract: The syntheses of 3,6-dineopentoxyphthalonitrile and 3,4,5,6tetraneopentoxyphthalonitrile are described. Condensation of these phthalonitriles with nickel chloride in lr'.N-dimethylarninoethanol yielded 1,4,8,11,15,18,22,25-octaneopentoxyphthalocyaninato nickel(Il) (3) and 1,2,3,4.8.9,10,11,15,16,17,18.22,23,24.25-hexadecaneopentoxyphtlralocyaninato nickel(Il) (7). The rH NMR spectra of these phthalocyanines and the related 2,3,9,10,16,17,23,24-octaneopentoxyphthalocyaninato R6sum6 : On ddcrit les synthdses des 3,6-din6opentoxy-et 3,4,5,6-tdtrandopentoxyphtalonitriles. La condensation de ces phtalonitriles avec du chlorure de nickel dans du N,N-dim6thylaminodthanol conduit d la formation des 1,4,8,11,15,18,22,25-octan6opentoxyphtalocyaninato nickel(il) (3) et 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24, (3,8), and nonlinear optics (9-l l). Applications of peripherally unsubstituted phthalocyanines are limited due their insolubility in common organic solvents and water (10, 1 l). Phthalocyanines possess an extended aconjugated electron system which pennits n stacking (aggregation) betu'een planar macrocycles, provided the distance between the macrocycles is small (10). Adding substituents to the periphery of the macrocycles increases their solubility since these substituents increase the distance between the stacked phthalocyanines and enable their solvation (10,12

4,5-Dineopentoxyphthalonitrile was prepared from catechol and neopentyl tosylate in three steps. Condensation of this substituted phthalonitrile with lithium metal in 1-pentanol led to 2,3,9,10,16,17,23,24-octaneopentoxyphthalocyanine. Lithiation in tetrahydrofuran gave the dilithium phthalocyanine which on methylation did not give the expected N -methylated product 29,31-dimethylphthalocyanine. The precipitate formed on methylation appeared to be the N +- CH 3 derivative in which one of the peripheral nitrogens was N -methylated. Methylation with 13 CH 3 I likely yielded an N +-methylated phthalocyanine having the requisite increased mass in its mass spectrum.

The palladium-catalyzed cyanation of aryl bromides and iodides to the corresponding nitriles occurs at room temperature when tri-t-butylphosphine is used as ligand, Zn(CN) 2 as the cyanide source and Zn dust as a co-catalyst in DMF as solvent. A variety of aromatic halides, including electron-withdrawing and electrondonating, can be efficiently cyanated under these conditions. The reactions are completed in less than 1 hour and products are produced in good to excellent yield.Aryl nitriles are important synthetic intermediates in the pharmaceutical industry because they serve as building blocks for a number of different functionalities with interesting biological properties. 1 The most direct method for the synthesis of aryl nitriles is the transition metal-catalyzed cyanation of aryl halides. 2 Although a number of elegant methods have been developed, the general procedure calls for elevated temperatures and in many cases long reaction times. In the course of our work, we needed a mild method for the preparation of aryl cyanide from an aryl bromide and thus explored other reaction conditions. We focused on the possibility of using a palladium(0) catalyzed process since palladium catalysts can be fine-tuned to perform a number of reactions at lower temperature. For example, during the past few years, the use of tri-t-butylphosphine as ligand in a variety of palladium-catalyzed processes, including Suzuki, 3 Heck, 4 Negishi, 5 Sonogashira, 6 amination of aryl halides 7 and Stille 8 couplings have been reported to occur under very mild conditions. Encouraged by these reports, we explored conditions for the cyanation of aryl halides using a Pd-P(t-Bu) 3 catalyst system.The use of Zn(CN) 2 as the cyanide source in the palladium-catalyzed cyanation of aryl halides in DMF has been shown to be general and reliable, albeit at elevated temperatures. 2a,2c-e Using this protocol, with 4¢-bromoacetophenone as a model substrate, we explored a number of room temperature reaction conditions (Table 1). To our delight, with 2.5 mol% Pd 2 (dba) 3 , 5 mol% tri-t-butylphosphine and zinc as a co-catalyst, the reaction was complete in 1 hour and we obtained an excellent isolated yield of 4¢-cyanoacetophenone (Scheme 1) ( Table 1, entry 1). A lower catalyst loading greatly affected the yield. When 1.25 mol% Pd 2 (dba) 3 , and 2.5 mol% tri-t-butylphosphine were used, an isolated yield of 60% was obtained after one hour (Table 1, entry 2). Increasing the reaction time to two hours gave an improved yield of 75%. However when 0.62 mol% Pd 2 (dba) 3 and 1.25 mol% tri-t-butylphosphine were used no product was obtained (Table 1, entry 3). Scheme 1The reaction was also highly dependent on the ligand. A number of ligands which have been reported to be effective at higher temperatures for palladium-catalyzed cyanation reactions, were used in place of tri-t-butylphosphine. Replacement of tri-t-butylphosphine with PPh 3 , Dppf, Xantphos, or 2¢-dicyclohexylphosphinobiphenyl in the general procedure yielded no product after 1 hour at room temperatur...

The Room-Temperature Palladium-Catalyzed Cyanation of Aryl Bromides and Iodides with Tri-t-butylphosphine as Ligand. -The optimized title reaction uses Zn(CN) 2 as the cyanide source and Zn-dust as a co-catalyst in DMF as the solvent. -(RAMNAUTH, J.; BHARDWAJ, N.; RENTON, P.; RAKHIT, S.; MADDAFORD*, S. P.; Synlett 2003, 14, 2237-2239; York Univ., MCR Res. Inc., Toronto, Ont. M3J 1P3, Can.; Eng.) -Mais 10-093