Imides Sodium amide

Attempts by A. W. Titherley to make sodium imide, Na2NH, by the action of ammonia on sodium oxide gave sodamide, NaNH2t and water Na20+2NH3 ->2NaNH2+H20. The water at once decomposes the sodamide, forming sodium hydroxide and ammonia, but if the action be suddenly stopped some of the primary product—sodamide—can be obtained sodium oxide and sodamide do not react to any appreciable extent. Bee potassium and sodium amides for the properties. 

Determination of amino groups in aromatic polyamides, polyimides and poly(amides-imides). Sodium hydroxide fusion-gas chromatography... 

A few common composite anions have names ending in -ide, namely, -OH hydroxide -CK cyanide -NH2 amide -NH- imide - NH KH2 hydrazide -NH OH hydroxylamide. Treating these as the other -ide names we obtain HaOH sodium hydroxide, KGN potassium cyanide, and the like. Sodium amide (NaNH2) is often abbreviated to sodamide, but there is no need for this practice. Hydrogen azide seems... 

The reaction is applicable to the preparation of amines from amides of aliphatic aromatic, aryl-aliphatic and heterocyclic acids. A further example is given in Section IV,170 in connexion with the preparation of anthranilic acid from phthal-imide. It may be mentioned that for aliphatic monoamides containing more than eight carbon atoms aqueous alkaline hypohalite gives poor yields of the amines. Good results are obtained by treatment of the amide (C > 8) in methanol with sodium methoxide and bromine, followed by hydrolysis of the resulting N-alkyl methyl carbamate ... 

The imide proton N-3—H is more acidic than N-1—H and hence this position is more reactive toward electrophiles in a basic medium. Thus hydantoins can be selectively monoalkylated at N-3 by treatment with alkyl haUdes in the presence of alkoxides (2,4). The mono-A/-substituted derivatives (5) can be alkylated at N-1 under harsher conditions, involving the use of sodium hydride in dimethylform amide (35) to yield derivatives (6). Preparation of N-1 monoalkylated derivatives requires previous protection of the imide nitrogen as an aminomethyl derivative (36). Hydantoins with an increased acidity at N-1—H, such as 5-arylmethylene derivatives, can be easily monoalkylated at N-3, but dialkylation is also possible under mild conditions. 

Industrial Synthetic Improvements. One significant modification of the Stembach process is the result of work by Sumitomo chemists in 1975, in which the optical resolution—reduction sequence is replaced with a more efficient asymmetric conversion of the meso-cyc. 02Lcid (13) to the optically pure i7-lactone (17) (Fig. 3) (25). The cycloacid is reacted with the optically active dihydroxyamine [2964-48-9] (23) to quantitatively yield the chiral imide [85317-83-5] (24). Diastereoselective reduction of the pro-R-carbonyl using sodium borohydride affords the optically pure hydroxyamide [85317-84-6] (25) after recrystaUization. Acid hydrolysis of the amide then yields the desired i7-lactone (17). A similar approach uses chiral alcohols to form diastereomic half-esters stereoselectivity. These are reduced and direedy converted to i7-lactone (26). In both approaches, the desired diastereomeric half-amide or half-ester is formed in excess, thus avoiding the cosdy resolution step required in the Stembach synthesis. 

Treatment with sodium hypochlorite or hypobromite converts primary amines into N-halo- or N,N-dihaloamines. Secondary amines can be converted to N-halo secondary amines. Similar reactions can be carried out on unsubstituted and N-substituted amides and on sulfonamides. With unsubstituted amides the N-halo-gen product is seldom isolated but usually rearranges (see 18-13) however, N-halo-N-alkyl amides and N-halo imides are quite stable. The important reagent NBS is made in this manner. N-Halogenation has also been accomplished with other reagents, (e.g., sodium bromite NaBr02) benzyltrimethylammonium tribromide (PhCH2NMe3 Br3"), and NCS. The mechanisms of these reactions involve attack by a positive halogen and are probably similar to those of 12-47 and 12-49.N-Fluorination can be accomplished by direct treatment of amines °° or... 

A series of N-substituted narceine amides (Section III,D,1) was prepared from 101 under the action of primary amines (100). Acid-catalyzed dehydration transformed these amides to corresponding imides (ene lactams) of the ( )-narceine imide (117) type (100). Similar transformations were performed in the hydrastine series (101). JV-Methylhydrastine (98) when treated with dilute ammonium hydroxide gave hydroxy lactam 127, which was dehydrated to (Z)-fumaridine (113) (5). Sodium borohydride was able to reduce the stilbene double bond in 98 to produce saturated lactone 132 (5). 

Von Runge and Triebs used a solution of dinitrogen pentoxide in chloroform for the N-nitration of both amides and imides. Solutions of dinitrogen pentoxide in chlorinated solvents are not neutral nitrating agents when amides and imides are nitrated - the presence of acidic N-H protons in these substrates leads to the formation of nitric acid. Sodium fluoride acts like a base towards nitric acid and so its addition to these reactions can increase product yield. Sodium acetate has been used for the same purpose during the nitration of n-butyl-V, V -dimethylurea. The effectiveness of dinitrogen pentoxide for the V-nitration of ureas is further illustrated by its use in the conversion of 2-imidazolidinone to N, V -dinitro-2-imidazolidinone in 90 % yield. In the presence of sodium fluoride the yield for this reaction exceeds 90 %. 

Dinitrogen pentoxide in chloroform has been used for the iV-nitration of amides, imides and ureas, where yields are generally excellent.2-Imidazolidinone (21) is converted to N,N -dinitro-2-imidazolidinone (22) in greater than 90% yield with this reagent in the presence of sodium fluoride. ... 

A different approach to enantiotopic group differentiation in bicyclic anhydrides consists of their two-step conversion, first with (/ )-2-amino-2-phcnylethanol to chiral imides 3, then by diastereoselective reduction with sodium bis(2-methoxyethoxy)aluminum hydride (Red-Al) to the corresponding chiral hydroxy lactames 4, which may be converted to the corresponding lactones 5 via reduction with sodium borohydride and cyclization of the hydroxyalkyl amides 101 The overall yield is good and the enantioselectivity ranges from moderate to good. Absolute configurations of the lactones are based on chemical correlation. 

It is well documented that the isoimide is the kinetically favoured product and that isomerization yields the thermodynamically stable imide when sodium acetate is used as the catalyst. High catalyst concentrations provide maleimides with low isoimide impurity. The mechanism by which the chemical imidization is thought to occur is shown in Fig. 3. The first step in the dehydration reaction may be formation of the acetic acid-maleamic acid mixed anhydride. This species could lose acetic acid in one of the two ways. Path A involves participation by the neighboring amide carbonyl oxygen to eject acetate ion with simultaneous or subsequent loss of proton on nitrogen to form the isoimide. Path B involves loss of acetate ion assisted by the attack of nitrogen with simultaneous or subsequent loss of the proton on nitrogen to form the imide. If the cyclodehydration is run in acetic anhydride in the absence of the base catalyst, isoimide is the main reaction product. 

Poly(amide imide) Having Pendant Sodium Sulfonate Groups.85... 

Sulfo group-containing poly(amide imide) semipermeable membrane 35 from trimellitic anhydride sodium 3,5-dicarboxybenzenesulfonate, and 4,4 -diphenyl-methane diisocyanate have been prepared 90>. A 110 p-thick membrane gave water permeation 5601/m2 day and salt rejection 99.0% (0.5% aqueous NaCl solution, 25 °C, 42 kg/cm2), while a trimellitic anhydride-4,4 -diphenylmethanediisocyanate copolymer membrane gave 30 1/m2 day and 98.2%, respectively. 

Imidate salts are 0-alkyl derivatives of tertiary amides. Being activated tertiary amides, they are extremely reactive towards nucleophiles. There is instantaneous reaction with hydroxide ion they also react rapidly at room temperature with water under acidic conditions. When an imidate fluoro-borate salt such as 43 reacts with sodium hydroxide, it gives sodium fluoro-borate and the tetrahedral intermediate 44 which breaks down in an irrevers-... 

For the preparation of anthranilic acid the starting material is phthalimide, the cyclic imide ring of which is opened by alkaline hydrolysis in the first step of the reaction to give the sodium salt of phthalimidic acid (the half amide of phthalic acid). The intermediate undergoes the Hofmann reaction in the manner outlined on p. 783 yielding o-aminobenzoic acid (anthranilic acid). 

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