Nitrate Directive

The net effect of the sequence protect-mtrate-deprotect is the same as if the substrate had been nitrated directly Because direct nitration is impossible however the indirect route IS the only practical method... 

Nitration. Direct nitration of aromatic amines with nitric acid is not a satisfactory method, because the amino group is susceptible to oxidation. The amino group can be protected by acetylation, and the acetylamino derivative is then used in the nitration step. Nitration of acetanilide in sulfuric acid yields the 4-nitro compound that is hydroly2ed to -rutroaruline [100-01-6]. 

A more recent derivative with activities typical of the class is nitrazepam (21). Reaction of 2-amino-5-nitrobenzophe-none (19) with bromoacetylbromide affords the amide, 20. Ring closure in liquid ammonia gives nitrazepam (21). More simply, diazepinone, 22, can be nitrated directly at the more reactive C7 position with potassium nitrate in sulfuric acid. 

Where direct nitration results in degradation, a primary amine can be acylated, nitrated directly to form a secondary niiramine, which is then hydrolyzed to form the primary nitramine as exemplified in the following reaction sequence ... 

On the basis of these data, the following mechanism for reduction by hydrogen can be suggested. H2, activated over the Pt sites according to the Pt-catalyzed pathway discussed previously, reduces the stored nitrates directly to ammonia or, more likely, induces the decomposition of nitrates to gaseous NO, which are then reduced by H2 to NH3 over the Pt sites [overall reaction (13.47)]. Once ammonia has been formed, it can react with adsorbed nitrates and this reaction is very selective towards nitrogen. It is worth noting that the reaction of ammonia with NOx obeys the stoichiometry of reaction (13.49), which is different from that of the well-known NH3-NO SCR reaction because it implies the participation of nitrates. 

No studies were located regarding the rate and extent of absorption of thorium following dermal exposure of humans or animals. Absorption of thorium through the skin of animals can be inferred, however, because testicular effects were seen in rats following application of thorium nitrate directly to the lateroabdominal and scrotal skin (Tandon et al. 1975). 

The boiling point of isopropyl nitrate is 101-102°C. It can only be obtained indirectly from isopropyl iodide and silver nitrate. Direct nitration of isopropyl alcohol is difficult due to oxidation at the carbon atom carrying the secondary hydroxyl group. 

Systemic heat Large whirlpool Hubbard tank Decreased muscle/joint stiffness in large areas of the body Opioid and nonopioid analgesics skeletal muscle relaxants Severe hypotension may occur if systemic hot whirlpool is administered to patients taking peripheral vasodilators and some antihypertensive drugs (eg., alpha-1 antagonists, nitrates, direct-acting vasodilators, calcium channel blockers)... 

In the United States the Stengel process is used to produce anhydrous ammonium nitrate directly. In this process ammonia and 58% nitric acid are preheated with fresh steam and fed into a packed vertical tube reactor at 3.5 bar and 240°C. The mixture of NH4NO3 and steam is expanded into a vacuum in a centrifugal separator. After stripping with hot air, a 99.8% NH4NO3 melt is discharged onto a cooled steal belt, solidified and then broken up or granulated295. 

The nature of substituent in the arylene fragment significantly influences the nitration direction. For example, 3,5-dialkyl-l,2-benzisoxazoles are nitrated into the position 4 (the data about the formation of 3,5-dimethyl-7-nitro-l,2-benzisox-azole presented in [115] turned out to be wrong [119], whereas 3-alkyl-5-nitro derivatives occupy the position 7 [119]). The nitration of 7-methoxy-2-phenylben-zisoxazole affords 7-methoxy-2-phenyl-4-nitro derivative [126],... 

Benzoyl and acetyl nitrates direct the nitro group to the ortho position of substituted benzenes however, detailed procedures are lacking. Acetyl nitrate is presumed to be present in solutions of nitric acid in acetic anhydride. Another reagent is the combination of nitrogen tetroxide and sulfuric acid. A review of these and other nitration processes to 1950 has been made in addition, the general mechanisms of aromatic nitrations have been extensively studied. ... 

The theory that sulphonation takes place before the nitration can be accomplished may be the key to the question as to why some mono- and dinitrotoluenes are easily nitrated, and some are difficultly nitrated. The sulphonic group follows the laws of orientation perhaps more closely than almost any other group, and this explains why (assuming the sulphonation theory) dilute nitric acid will not nitrate direct, but will merely replace a sulphonic group. Therefore, if the sulphonic group is not already in place, the nitro-group cannot enter the molecule. So, if the previous... 

This solution to the question would seem to indicate that in the first-stage nitration the sulphonation does not tahe place, but that the toluene is nitrated directly by the use of nitric acid. 

From Amino Benzoic Acid.—Amino acids by the diazo reaction and decomposition with water will yield the corresponding phenol acids. In such cases also if we start with benzoic acid, nitrate directly and reduce this to the amino compound, the final product of the diazo reaction will be the meta hydroxy acid. If we start with toluene and nitrate it and then proceed as in the foregoing and oxidize the amino toluene to amino benzoic acid our product will be the ortho and para hydroxy acids. 

When a small grain of shellac is dropped on the surface of melted potassium nitrate, the nitrate directly reacts on the shellac at the contact surface. In this case the surface of the potassium nitra te begins to move radially from the grain(Fig.5 ) ... 

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