Alkaline synthetic routes

The massive contamination of NDE1A in alkaline synthetic fluids (3%) found by Fan et al Q) cannot be explained by known nitrosation kinetics of di- or triethanolamine. Instead, more powerful nitrosation routes, possibly involving nitrogen oxide (N0X) derivatives (e.g., N02> N O t) may be responsible for the amounts of NDE1A in these products (34). In fact, a nitrite-free commercial concentrate was shown to accumulate NDE1A up to about 10 0 days at which time the levels dropped dramatically (19). Inhibition of N0X contaminants may be an effective route to the inhibition of nitrosamine formation in metalworking fluids. 

Marchand and co-workers reported a synthetic route to TNAZ (18) involving a novel electrophilic addition of NO+ NO2 across the highly strained C(3)-N bond of 3-(bromomethyl)-l-azabicyclo[1.1.0]butane (21), the latter prepared as a nonisolatable intermediate from the reaction of the bromide salt of tris(bromomethyl)methylamine (20) with aqueous sodium hydroxide under reduced pressure. The product of this reaction, A-nitroso-3-bromomethyl-3-nitroazetidine (22), is formed in 10% yield but is also accompanied by A-nitroso-3-bromomethyl-3-hydroxyazetidine as a by-product. Isolation of (22) from this mixture, followed by treatment with a solution of nitric acid in trifluoroacetic anhydride, leads to nitrolysis of the ferf-butyl group and yields (23). Treatment of (23) with sodium bicarbonate and sodium iodide in DMSO leads to hydrolysis of the bromomethyl group and the formation of (24). The synthesis of TNAZ (18) is completed by deformylation of (24), followed by oxidative nitration, both processes achieved in one pot with an alkaline solution of sodium nitrite, potassium ferricyanide and sodium persulfate. This route to TNAZ gives a low overall yield and is not suitable for large scale manufacture. 

The formation of a Reissert anion (intermediate of type 16) is usually the introductory step in a great number of synthetic routes leading to isoquinoline as well as indole alkaloids and related compounds. On the one hand, the alkylation of a Reissert anion with alkyl halide followed by alkaline hydrolysis is the most frequently used method for the synthesis of 1-alkyl- or 1-arylalkylisoquinolines (20) (Scheme 4). On the other hand, Reissert anions react with aldehydes to form... 

Attachment of substituents incompatible to ozone required a different general synthetic route. For example, allyl acid 59 displayed poor chemoselectivity on exposure to ozone. Contrary to reports of alkaline decomposition of the lactone-acetal-peroxide functionality,16 the enolate of the prefabricated tetracycle 42 could be generated at low temperature and alkylated. As a notable example, this methodology produced a single allylated tetracycle, the a-epimer 59. This initial alkylation product was unchanged after prolonged acid treatment, and structure 57 was... 

Another synthetic route proposed by von Baeyer began with o-nitrocinnamic acid (7) and led to o-nitrophenylpropiolic acid (8), which could be converted to indigo directly on the textile fiber with mild reducing agents under alkaline con-... 

Despite the chemical diversity of the several hundred structures representing herbicidal activity, most reactions of herbicides fall within only a limited number of mechanistic types oxidation, reduction, nucleophilic displacements (such as hydrolysis), eliminations, and additions. "Herbicides", after all, are more-or-less ordinary chemicals, and their principal transformations in the environment are fundamentally no different from those in laboratory glassware. Figure 2 illustrates three typical examples which have received their share of classical laboratory study—the alkaline hydrolysis of a carboxylic ester (in this case, an ester of 2,4-dichlorophenoxyacetic acid, IX), the cycloaddition of an alcohol to an olefin (as in the acetylene, VI), and the 3-elimination of a dithiocarbamate which provides the usual synthetic route to an isothiocyanate (conversion of an N.N-dimethylcarbamic acid salt, XI, to methyl isothiocyanate). Allow the starting materials herbicidal action (which they have), give them names such as "2,4-D ester" or "pronamide" or "Vapam", and let soil form the walls of an outdoor reaction kettle the reactions and products remain the same. 

The principal synthetic route to diazafluorenes involves the alkaline oxidation of phenanthrolines, presumed to give initially the rarely isolated 5,6-dione which (i) further oxidizes to a bipyridyl dicarboxylic acid (the main product) or (ii) undergoes a benzilic acid type rearrangement followed by oxidative decarboxylation to give diazafluorenones in moderate yields (Scheme 2) <77JPR959>. The process has been reviewed by Summers <78AHC(22)i>. The yields of 4,5-diazafluorenone have been optimized <73AJC2727>. 

The spirodihydropyridine 24 thus obtained was converted to the corresponding azaberbines (25 and 26) by alkaline hydrolysis, followed by photolysis (6useful synthetic route for the alkaloids such as nauclefine 68). Similarly, the formation of spirodihydropyridines was observed from acylation of harma-lane and the open-chain 3-aminocrotonate 70). 

Marquillas Olondriz et al. (8) described a synthetic route consisting of oxidation of 3-acetyl-6,8-difluoro-l-methyl-7-(4-ethoxycarbonyl-3-methyl-l-piperazinyl)-4-oxo-l,4-dihydroquinoline to yield the 3-carboxylic analog, followed by deprotection of the piperazinyl amino group by aqueous alkaline hydrolysis. The oxidation may be carried out with sodium hypochlorite or sodium hypobromite. Sodium hydroxide or potassium hydroxide may be used for the alkaline hydrolysis. The reaction yield was 72 %. The results of the elemental analysis were ... 

Synthetic routes to vinylpyrroles and vinyl indoles continue to be of interest because of their potential as Diels-Alder dienes. Work by Settambolo and coworkers demonstrated that 3-acyl-l-p-toluenesulfonylpyrroles can be converted to 3-vinylpyrroles by standard methods such as Wittig olefination or organometallic addition followed by dehydration. <94G173> The tosyl group can be removed by alkaline hydrolysis. 

As a fundamental class of compounds in the fields of synthetic solid-state (and also molecular) chemistry, cyanamides and carbodiimides have gained increasing attention within the past decade. Because of their 2-fold anionic charge, both cyanamide and carbodiimide structural units allow the realization of nitrogen-based pseudo-oxide chemistry since NCN is able to replace in a wide variety of novel materials. A number of alkali metal, alkaline-earth metal, main-group metal,divalent transition-metal, trivalent rare-earth metal,and also triva-lent transition-metal cyanamides/carbodiimides were obtained following different synthetic routes. The only carbodiimide containing divalent lanthanide ions was reported by DiSalvo et al., who found that EuNCN is isostructural to the already known a-SrNCN. ... 

In principle, the preparation of these compounds should be similar to the chemistry of carboxylic acids and sulfonic acids, but it is more complex and there are synthetic routes that are specific for the phosphorus compounds. For example, the reaction of phosphoric acid and an alcohol may give the ester, but the reaction is slow and this is not a good preparative method. An alternative is the reaction of phosphorous pentoxide with an excess of an alcohol to give a mixture of phosphate esters. The reaction of ethanol and P4O10 (the dimeric form of phosphorus pentoxide), for example, gives a mixture of 207 and 208. They are separable based on differences in solubility in alkaline earth salts.The hydrolysis of pyrophosphate esters such as 209 gives the phosphate ester 208. 

Ribonucleic Acid. A major contribution to the formulation of RNA structure was the demonstration that alkaline hydrolysis of RNA quantitatively liberates about equal amounts of mononucleotide isomers of all four bases 103). Although it was readily established that none of these mononucleotides is the 5 -phosphate isomer, it was not until some years later that Cohn and associates 103) by controlled degradation experiments, and Brown and associates 121) by the synthetic route, established that the products were isomers involving phosphate attachment at positions 2 and 3 of the ribose. Of equal significance was the discovery 161) that hydrolysis of RNA by the enzyme phosphodiesterase (snake venom or intestinal) liberates mononucleotides exclusively of still another type, the 5 -mono-nucleotides. It was thus necessary to establish the mechanisms which could account for one phosphodiester structure in the RNA chain giving rise to three isomers of each mononucleotide. 

The easiest synthetic route is to use inert polymers (as above) doped with concentrated KOH(aq) (as above) polybenzimidazole (PBl) [57-61], poly(vinyl alcohol) (PVA) [44], composite polymers such as PVA/hydroxyapatite (PVA/HAP) [62], quatemized-PVA/alumina (QPVA/AI2O3) [63], PVA/titanium oxide (PVA/ Ti02) [64,65], chitosan and cross-linked chitosan [66-68], copolymers of epichlo-rohydrin and ethylene oxide [69], and cross-Unked PVA/sulfosuccinic acid (10 wt. % SSA) [70] have aU been doped with KOH and used as AEMs. Patent US5569559 [71] describes the use of polar polymers (most preferred being polyethylene oxide) doped with alkaline metal hydroxides (such as KOH), alkaline earth metal... 

The development of the heavy alkaline-earth metal bis(bis(trimethylsilyl)amides, M[N(SiMe3)2]2(thf)2, has been instrumental in the use of the transaminadOTi route as a viable and dependable synthetic route towards the preparadmi of alkaline-earth metal compounds. The amides, M[N(SiMe3)2]2(thf)2, can be prepared via salt metathesis involving treatment of the metal halides with alkali metal amide (Ca-Ba) [182, 183]. The heavier metal (Sr, Ba) amides can also be obtained by direct metallation in liquid, anhydrous ammonia (Sr and Ba) [83,90,91, 184-187]. 

Amine oxides, or more correctly amine oxides of tertiary amines, are nonionic in an alkaline or neutral solution but cationic in acid solutions. The synthetic routes to amine oxides and cationic surfactants are similar. Although amine oxides are intrinsically nonionic, they may be considered to belong to the class of cationic surfactants. 

The other major route to quinone diazides is based on the alkaline hydrolyses of mono-4-toluenesulfohydrazones of quinones, which will be discussed in Section 2.6. In the same section other synthetic methods are briefly discussed. 

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