Methods, primary and secondary

FAULT PROTECTION AND SYSTEM COORDINATION SWITCHGEAR LOCATION AND WIRING WIRING METHODS Primary and Secondary Feeders Busways... 

TBDMSCl-Assisted Reactions. Nitro aldol (Henry) reactions have been reported to be promoted by TBDMSCl. To a THF solution of tetra-n-butylammonium fluoride is added sequentially equimolar amounts of the nitro compound, aldehyde, and EtsN, followed by an excess of TBDMSCl (eq 11). Substitution of TMSCl for TBDMSCl reduces the yield of nitro aldol product. The authors speculate that TBDMSCl is responsible for activation of the aldehyde while n-Bu4NF activates the nitro compound. In a related method, primary and secondary nitro alkanes were treated with LDA in THF followed by addition of TBDMSCl to give the corresponding silyl nitronates. The silyl nitronates reacted with a variety of aliphatic and aromatic aldehydes which gave vicinal nitro TBDMS aldol products. ... 

Kinetic Method - Primary and Secondary Hydroxyi Groups... 

It has developed a real time method to compare successive non-destructive inspections of the steam generator tubes in nuclear power plants. Each tube provides a safety barrier between the primary and secondary coolant circuits. Each steam generator contains several thousands of tubes whose structural integrity must be ensured through the lifetime of the plant, Therefore, Laborelec performs extensive nondestructive tests after each plant outage. 

Dimethyl Sulphate Method for hydroxy compounds and for primary and secondary amines, acid amides, etc. The substance is dissolved or suspended in water, a small excess (above the theoretical) of sodium hydroxide added and then the theoretical quantity of dimethyl sulphate, the mixture being finally shaken without external warming. Methylation is usually rapid, the dimethyl sulphate being converted to methyl hydrogen sulphate... 

Diasomethane Method. Diazomethane readily methylates phenolic hydroxy-compounds, primary and secondary amines, and carboxylic acids,... 

The Formaldehyde-Formic Acid Method, This method applies to primary and secondary amines, which when boiled with a formalin-formic acid mixture undergo complete methylation to the corresponding tertiary amine. This method has the advantage over the dimethyl sulphate method in that quaternary salts clearly cannot be formed. 

If the molecular weight of the aniline is known, the number of amino groups can be calculated alternatively, if the aniline is known to be a monacidic base, its molecular weight can be calculated. If the molecular weight and the acidity of the aniline are both known, then dearly the method can be used to estimate the amount of aniline in a given sample. The method is general for many primary and secondary amines, aniline being used solely as a typical member of the former class. 

Method 1. Treat 2 0 g. of the mixture of amines with 40 ml. of 10 per cent, sodium hydroxide solution and add 4 g. (3 ml.) of benzenesulphonyl chloi de (or 4 g. of p-toluenesulphonyl chloride) in small portions. Warm on a water bath to complete the reaction. Acidify the alkaline solution with dilute hydrochloric acid when the sulphonamides of the primary and secondary amines are precipitated. Filter off the solid and wash it with a little cold water the tertiary amine will be present in the filtrate. To convert any disulphOnamide that may have been formed from the primary amine into the sulphonamide, boil the solid under reflux with 2 0 g. of sodium dissolved in 40 ml. of absolute ethyl alcohol for 30 minutes. Dilute with a little water and distil off the alcohol filter off the precipitate of the sulphonamide of the secondary amine. Acidify the filtrate with dilute hydrochloric acid to precipitate the derivative of the primary amine. Recrystallise the respective derivatives from alcohol or from dilute alcohol, and identify them inter alia by a determination of the m.p. 

Hinsberg procedure for the separation of primary, secondary and tertiary amines is given under (viii) above, and this method may be used. The following experimental details may, however, be found useful for the preparation of derivatives of primary and secondary amines. 

Derivatives with 3-nitrophthalic anhydride. 3-Nitrophthalic anhydride reacts with primary and secondary amines to yield nitro-phthalamic acids it does not react with tertiary amines. The phthalamic acid derived from a primary amine undergoes dehydration when heated to 145° to give a neutral A -substituted 3-nitrophthalimide. The phthalamic acid from a secondary amine is stable to heat and is, of course, soluble in alkali. The reagent therefore provides a method for distinguishing and separating a mixture of primary and secondary amines. 

The first practical method for asymmetric epoxidation of primary and secondary allylic alcohols was developed by K.B. Sharpless in 1980 (T. Katsuki, 1980 K.B. Sharpless, 1983 A, B, 1986 see also D. Hoppe, 1982). Tartaric esters, e.g., DET and DIPT" ( = diethyl and diisopropyl ( + )- or (— )-tartrates), are applied as chiral auxiliaries, titanium tetrakis(2-pro-panolate) as a catalyst and tert-butyl hydroperoxide (= TBHP, Bu OOH) as the oxidant. If the reaction mixture is kept absolutely dry, catalytic amounts of the dialkyl tartrate-titanium(IV) complex are suflicient, which largely facilitates work-up procedures (Y. Gao, 1987). Depending on the tartrate enantiomer used, either one of the 2,3-epoxy alcohols may be obtained with high enantioselectivity. The titanium probably binds to the diol grouping of one tartrate molecule and to the hydroxy groups of the bulky hydroperoxide and of the allylic alcohol... 

Primary and secondary amines are susceptible to oxidation and replacement reactions involving the N—H bonds. Within the development of peptide synthesis numerous protective groups for N—H bonds have been found (M, Bodanszky, 1976 L.A. Carpino, 1973), and we shall discuss five of the more general methods used involving the reversible formation of... 

Carbonylation of halides in the presence of primary and secondary amines at I atm affords amides[351j. The intramolecular carbonylation of an aryl bromide which has amino group affords a lactam and has been used for the synthesis of the isoquinoline alkaloid 498(352], The naturally occurring seven-membered lactam 499 (tomaymycin, neothramycin) is prepared by this method(353]. The a-methylene-d-lactam 500 is formed by the intramolecular carbonylation of 2-bromo-3-alkylamino-l-propene(354]. 

Although acetyl chloride is a convenient reagent for deterrnination of hydroxyl groups, spectroscopic methods have largely replaced this appHcation in organic chemical analysis. Acetyl chloride does form derivatives of phenols, uncompHcated by the presence of strong acid catalysts, however, and it finds some use in acetylating primary and secondary amines. 

Triple-distiUed mercury is of highest purity, commanding premium prices. It is produced from primary and secondary mercury by numerous methods, including mechanical filtering, chemical and air oxidation of impurities, drying (qv), electrolysis, and most commonly multiple distillation. 

A general one-step method for preparation of primary and secondary nitroparaffins from amines by oxidation with y -chloroperbenzoic acid in 1,2-dichloroethane has been reported (68). This method is particularly useful for laboratory quantities of a wide variety of nitroparaffins because a large number of amines are readily available from ketones by oxime reduction and because the reaction is highly specific for nitroparaffins. 

A titration method for primary and secondary nitroparaftins uskig hypochlorite gives good accuracy ( 0.1%) (84). It is based on the foUowkig equation ... 

In general, if the desired carbon—phosphoms skeleton is available in an oxidi2ed form, reduction with lithium aluminum hydride is a powerful technique for the production of primary and secondary phosphines. The method is appHcable to halophosphines, phosphonic and phosphinic acids as well as thein esters, and acid chlorides. Tertiary and secondary phosphine oxides can be reduced to the phosphines. 

The reaction of alcohols and acid chlorides in the presence of magnesium has been described (68). With primary and secondary alcohols the reaction is very smooth, and affords high and sometimes quantitative yields. Difficulty esteritiable hydroxy compounds such as tertiary alcohols and phenols can be esteritied by this method. The reaction carried out in ether or benzene is usually very vigorous with evolution of hydrogen. 

Electrolysis, Bu4N Br, H2O, CH3CN, NaHC03- This method is unsatisfactory for primary and secondary alcohols, aldehydes, olefins, or amines. 

There are essentially three methods which have been used for incorporation of the glycerol unit in macrobicyclic species. In all of these the pervasive problem is the tendency of glycerol to form five-membered acetals involving the primary and secondary hydroxyls rather than the two primary hydroxyls and the tendency of the glycerol equivalent 1,3-dichloro-2-propanol to form epichlorohydrin. 

If homolytic reaction conditions (heat and nonpolar solvents) can be avoided and if the reaction is conducted in the presence of a weak base, lead tetraacetate is an efficient oxidant for the conversion of primary and secondary alcohols to aldehydes and ketones. The yield of product is in many cases better than that obtained by oxidation with chromium trioxide. The reaction in pyridine is moderately slow the intial red pyridine complex turns to a yellow solution as the reaction progresses, the color change thus serving as an indicator. The method is surprisingly mild and free of side reactions. Thus 17a-ethinyl-17jS-hydroxy steroids are not attacked and 5a-hydroxy-3-ket-ones are not dehydrated. 

Extension of this reaction to other substrates, however, revealed that it is more complex, and that side products are formed depending on (1) the nature of the substrate, (2) the reaction conditions, e.g. temperature and solvent,and (3) the method of work-up." Thus, in addition to the desired substitution products, primary and secondary hydroxy steroids generally yield esters and ethers and undergo simple dehydration as well as dehydration accompanied by rearrangement. 

In Barton s method, the base used for the enolization step assumes some importance -butoxide is clearly superior, even though enolization could be demonstrated with primary and secondary alkoxides. 

Note the preferential reaction at the anomeric hydroxyl. The method is also effective for the protection of primary and secondary alcohols. 

When the substrate does not contain a reactive carbon-carbon double bond, the ozonolysis procedure appears to provide a convenient and efficient method for the conversion of primary and secondary nitro compounds into carbonyl compounds fEq. 6.7. ... 

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