Meta salts, synthesis

The molybdenum-mediated arylamine cyclization was also applied to the total synthesis of pyrano[3,2-a]carbazole alkaloids (Scheme 26). Reaction of the 5-aminochromene 71 with the complex salt 62 affords the complex 72, which on oxidative cyclization provides girinimbine 73, a key compound for the transformation into further pyrano[3,2-a] carbazole alkaloids. Oxidation of 73 with DDQ leads to murrayacine 74, while epoxidation of 73 using meta-chloro-perbenzoic acid (MCPBA) followed by hydrolysis provides dihydroxygirinim-bine75 [113]. 

Using the same methodology, from ortho, meta, and para dicyanobenzenes compounds 82, 83, and 84 were synthesized in yields of 75%, 85%, and 92% <1991CC369>. As expected, para derivative 84 gave the most stable crystal lattice, presumably due to its linear nature. Further work in the same laboratory involved the synthesis of the 5,5, 5"-(l,3,5-phenylene)tris(l,3,2,4-dithiadiazolium)tri(hexafluoroarsenate) salt 85 in 80% yield. 

Answer The meta substitution pattern of Xll-g looms as the major difficulty in this-synthesis. The ethoxy group is an ortho iara director while the cyano function is a meta director. It appears that an easy approach to take would be to nitrate benzonitrile, reduce the -NO, group to the amine, diazotizc, and treat the diazonium salt with ethanol. However, jl is not feasible to reduce the -NO, group of meta-nitrobenzonitrilc without also reducing the -CN group. 

A series of unusual amidinium benzomorphans has been described by Strauss et a/.<53 55) where some members of the series exhibit narcotic antagonist properties. Their synthesis involves a meta bridging process of di- and trinitronaphthalenes (116) with a-phenyl N,N-dimethylacetamidine (117) to produce two isomeric benzazocine amidinium nitronates as their a-phenyl-N,N-dimethylacetamidinium salts (AmH+). The benzomorphan 118 is formed in ethanolic solution, whereas the isomeric benzazocine (119) results from reaction in dimethylsulfoxide. 

The photolysis of triarylsulphonium salts yields diarylsulphides and products of lateral nuclear shift reactions which are ortho, meta, and para aryl substituted diaryldisulphides such as (342). A by-product in these reactions is a proton because of this these reactions have been applied to photoinitiation of cationic polymerisations. A full paper describing a detailed study of the reaction mechanism has been published.In addition, the product distribution obtained by photolysis of triphenylsulphonium salts in films of the polymer of 4-(tert -butoxycarbonyloxy)styrene has been compared with that obtained in solution.The synthesis of some new triarylsulphonium salts and their application for photoinitiation of cationic polymerisation has also been reported.The formation of the products arising from lateral nuclear shifts in sulphonium salts occurs under direct photolysis but not under triplet sensitisation. 

Blaugas Coal Coal briquettes, hot Coal gas, 2.3 Coal gas, compressed, 2.1, 2.3 Coal tar, crude and solvent Coal tar distillates, flammable, 3, 3.2,3.3 Coal tar naphtha Coal tar oil Coke, hot Creosote Creosote (coal tar or wood tar) Creosote salts Cresols (o-, m-, p-), 6.1, 8 Cresols (ortho- meta- para-), liquid or solid, 6.1 Dead oil Fischer Tropsch gas Fischer-Tropsch gas compressed, 2.2 Iron oxide, spent (obtained fix)m coal gas purification), 4.2 Iron sponge, spent, 4.2 Iron sponge, spent (obtained from coal gas purification), 4.2 Prilled coal tar Synthesis gas Synthesis gas, compressed Water gas Water gas, compressed... 

Based on the ability of Pd(OAc)2 to accelerate the [2,3]-rearrangement of amine iV-oxide 114, we explored chiral palladium(ll) salts to catalyze the enantioselective rearrangement. When we treated amine iV-oxides 116 with Pd(OAc)2 and chiral phosphoramidite 118, chiral O-allylhydroxylamines 117 were isolated in 80-85% ee (Scheme 1S.28V Subsequent optimization revealed the beneficial effect of methanol and meta-chlorobenzoic acid (m-CBA) as additives, allowing the isolation of chiral nonracemic O-allylhydroxylamines 117 with greater than 90% enantioenrichment. This palladium-catalyzed enantioselective [2,31-rearrangement can tolerate a wide variety of functional groups in the amine N-oxide substrate. For example, we can synthesize chiral allylic hydrojq lamine products with reactive functional groups such as alcohols and aldehydes, which are inconpatible with many other methods for the synthesis of chiral alcohol derivatives. 

Carbonylation of cinnamyl acetate in the presence of NEt3, acetic anhydride, and catalytic amounts of a palladium phosphine complex such as Cl2Pd(PPh3)2 gives 1-naphthyl acetate in good yield (Scheme 2) Esterification of 1-naphthol, the initial product, by acetic anhydride is essential to avoid side reactions leading to a complex mixture. Cinnamyl bromide reacts similarly, but the yield is lower probably because formation of the quaternary ammonium salt from the bromide and NEts competes with the carbonylation. This reaction is applicable to the synthesis of various substituted 1-naphthyl acetates. In the reaction of cinnamyl acetates with a meta-substituent, two possible regioisomeric products are obtained, where the para-cyclization predominates. 

Related to the snbject of this chapter are obviously the weU-known Zintl phases. The generation of homopolyanions (Figure 2.1) was first reported by Zintl et al. [25] at the beginning of the 20th century. Their synthesis is based on the reduction of meta-metal salts (M = lead, tin, antimony, bismuth, and many others) by alkaline and alkaUne-earth metals in liqnid ammonia in chemically inert vessels [26-28], It was fonnd that the stability of complexes with Na+ or Cs+ is fairly weak. Their stability (case of posttransition metals) was found to be strongly increased by the nse of ayptates [29,30], Nevertheless, it shonld be anphasized... 

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