Acetonitrile novel catalysts

Formation of 2,7-octadienyl alcohol (32) by the reaction of water has attracted much attention as a novel practical synthetic method for n-octanol, which is of considerable industrial importance. However, the reaction of water under usual conditions of the butadiene telomerization is very sluggish. Atkins, Walker, and Manyik found that the presence of a considerable amount of carbon dioxide showed a very favorable effect on the telomerization of water (40). Reaction of water (2.0 moles) with butadiene (1.0 moles) using Pd(acac)2 and PPh3 as the catalyst was carried out in the presence of carbon dioxide (0.5 mole) at 80-90°C. tert-Butyl alcohol, acetone, and acetonitrile were used as solvents. The products that were obtained are shown in Eq. (21) and Table I. 

Kobayashi and Nagayama [26] have reported the preparation of a library of quinoline derivatives using a novel polymer-supported scandium catalyst (Fig. 8) in a three-component coupling reaction. The scandium catalyst has the advantage of being partially soluble in the dichloromethane/acetonitrile mixtures but can be precipitated by the addition of hexanes and thus be removed quantitatively by filtration. 

Shinde et al. (2008) have prepared silica gel-supported sodium hydrogen sulfate and demonstrated its application in the synthesis of coumarins. The reactions were conducted in acetonitrile and the reaction time in most of the cases was 1 h, which included the weakly reactive naphthols. Application of nanocrystalline sulfated zirconia in the reaction of meta-substituted phenols has also been investigated (Tyagi et al. 2007) under different conditions. In view of the slow reaction rates observed in nitrobenzene and toluene, the solvent-free conditions were adopted under MW irradiation to obtain high yields (95%-99%), of 7-amino- and 7-hydroxy-4-methylcoumarins in the reaction of m-amino and m-hydroxy phenols with ethyl acetoacetate. A low percentage of catalyst is required and its reusability has been claimed as a novel feature of this synthesis. 

A novel preparative synthesis of aporphines which should prove of appreciable utility in the future involves the cathodic cyclization of a l-(o-iodo-benzyl)isoquinoline methiodide salt. Gottlieb and Neumeyer have shown that electrolysis of l-(o-iodobenzyl)isoquinoline methiodide in dry acetonitrile containing tetraethylammonium bromide, and using a mercury cathode, furnished an 867o yield of the yellow didehydroaporphine which was reduced over Adams catalyst in methanolic hydrochloric acid to produce aporphine hydrochloride. The formation of didehydroaporphine proceeds via two one-electron reduction steps as shown below. 10,11-Dimethoxyaporphine was also prepared by this route. 

Dioxiranes for alkene epoxidation may be prepared in situ from a catalytic amount of a ketone and Oxone (potassium peroxymonosulfate triple salt). )V,)V-Dimethyl-and A, A -dibenzylalloxans (20a) and (20b) (Figure 3) have been prepared and used as novel dioxirane catalysts for the epoxidation of a range of di- and tri-substituted alkenes in good to excellent yield. H2O2 (rather than the usual Oxone) has been successfully used as primary oxidant in asymmetric epoxidations with Shi s fructose-derived ketone (21) in acetonitrile. The ketone is converted into the dioxirane, which is responsible for epoxidation and the active oxidant responsible for dioxirane formation is proposed to be peroxyimidic acid formed by combination of H2O2 with acetonitrile. ... 

One novel approach reported by Bianchini and coworkers is exploring a new strategy of incorporation the nitrogen atom at the C-6 position via iV-benzyl intermediates. The synthetic route, as depicted in Scheme 22, starts from primary tosylates, which were converted into iV-benzylamino intermediates and then debenzylated via a standard hydrogenation with gaseous hydrogen in the presence of the Pd/C catalyst and acetic acid in acetonitrile solution. 

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