Ammonia, reaction with potassium

Chloroacetate esters are usually made by removing water from a mixture of chloroacetic acid and the corresponding alcohol. Reaction of alcohol with chloroacetyl chloride is an anhydrous process which Hberates HCl. Chloroacetic acid will react with olefins in the presence of a catalyst to yield chloroacetate esters. Dichloroacetic and trichloroacetic acid esters are also known. These esters are usehil in synthesis. They are more reactive than the parent acids. Ethyl chloroacetate can be converted to sodium fluoroacetate by reaction with potassium fluoride (see Fluorine compounds, organic). Both methyl and ethyl chloroacetate are used as agricultural and pharmaceutical intermediates, specialty solvents, flavors, and fragrances. Methyl chloroacetate and P ionone undergo a Dar2ens reaction to form an intermediate in the synthesis of Vitamin A. Reaction of methyl chloroacetate with ammonia produces chloroacetamide [79-07-2] C2H ClNO (53). 

In a series of reactions with potassium amide in liquid ammonia, 6-chloropyrido[2,3-f)]pyrazine gave reduction and ring contraction (Section 2.15.13.3), the 6-bromo analogue underwent only reduction, whilst the 6-fluoro derivative gave only the 6-amino substitution product (79JHC305). 

An earlier report (126) which assigned the irons configuration to the enamine (175) derived from the cyanamine (176) upon reaction with potassium amide in liquid ammonia has been questioned by Munk and Kim (725). They also have doubts about the structures (177 and 178) proposed for the products obtained by the reduction of acetonitrile with sodium (727). 

Diazotization of 3-amino-2-acetylselenophene (105) and reaction with potassium selenocyanide yields the selenocyanate (106) ring closure with ammonia gives the fused system 107 which was O-methylated with dimethyl-sulfate.135... 

The synthesis of 1,3-selenazoles from A -phenylimidoyl isoselenocyanates has been reported. N-phenylimidoyl isoselenocyanates 94 are prepared from N-phenylbenzamides 92. Treatment of 92 with thionyl chloride affords N-phenylbenzimidoyl chlorides 93, which yield imidoyl isoselenocyanates 94 on reaction with potassium isoselenocyanate. The imidoyl isoselenocyanates 94 were transformed into selenoureas 95 with either ammonia or primary or secondary amines. Reaction of 95 with an activated bromomethylene compound such as bromoacetophenone in the prescence of a base gave the 1,3-selenazole 97 via the salt 96 <00HCA1576>. 

Phenylpyrimidine. Amination of 5-phenylpyrimidine showed about the same results as obtained with 4-phenylpyrimidine (82MI1). Reaction with potassium amide/liquid ammonia for 20 hr at 33°C and quenching of the reaction mixture with ammonium chloride yielded both 2-amino-5-phenylpyrimidine (70/73, 20%) and 6-amino-5-phenylpyrimidine (72, 20%). Investigations by and NMR spectroscopy of solutions of 5-phenylpyrimidine in potassium amide/liquid ammonia clearly showed the presence of the 4(6)-amino adduct hardly any indication for the presence of the 2-amino adduct was observed (Scheme 11.34). 

Of special interest is the reaction with potassium cyanate (Scheme 34) [11b] which turned out to be essentially a new method of chlorine substitution with a protected ammonia equivalent. 

Triazine and some of its 3-methoxy, 3-methylthio or 3-amino derivatives (103) with the 5-position unsubstituted react with potassium cyanide to afford two products, the i-triazinyls (105) and the l,2,4-triazine-5-carboxamides (104). These are proposed to be formed via a cyanide adduct (73JHC343, 74JHC43). The bi-l,2,4-triazinyls (105) were also isolated when the triazines (103) were treated with sodium methoxide or potassium in liquid ammonia. It is suggested that the methoxide-catalyzed dimerization proceeds via an anionic intermediate (106), while the reaction with potassium in liquid ammonia occurs via a free radical process. 

A solution to the question of the mechanism of these reactions was provided by John D. Roberts in 1953 on the basis of an imaginative experiment. Roberts prepared a sample of chlorobenzene in which one of the carbons, the one bearing the chlorine, was the radioactive mass-14 isotope of carbon. Reaction with potassium amide in liquid ammonia yielded aniline containing almost exactly half of its 14C label at C-l and half at C-2 ... 

This synthetic route can be usefiil for organic molecules with exceptionally acidic protons, such as acetylenes or cyclopentadienes. These reactions often require the alkali metal to be present as very small particles. Sodium sand can be formed by refluxing in THF with minor agitation to break up the sodium into tiny particles. Reactions with potassium may require a mirror that can be formed by dissolving potassium metal in liquid ammonia followed by evaporation of the ammonia from the reaction vessel. Ultrasound has also been used to aid in the formation of organolithium compounds from lithium metal. 

It has recently been found that purine in its anionic form undergoes a Chichibabin reaction with potassium amide in liquid ammonia with formation of adenine as the sole product. 

Haloalkyl phenyl sulfides produce cycloalkyl phenyl sulfides on treatment with base. The synthesis of cyclopropyl phenyl sulfides has attracted particular interest since these compounds can be metal-lated - - by Bu"Li in THF and the resulting 1-phenylthiocyclopropyllithium has been used for spiro-annelation of various cycloalkanones. - Thus, 3-chloro-l-phenylthiopropane leads to phenylthiocyclopropane on reaction with potassium amide in liquid ammonia (Scheme 7, entry a), but attempts to prepare 2-methylcyclopropyl phenyl sulfide from 3-chloro-l-phenylthiobutane by an analogous route failed in the cyclization step. Neither 3-mesyloxy- and 3-tosyloxy-l-phenylthiododecanes " nor 3-tosyloxy-l-phenylthiobutane produce cyclopropane derivatives either on reaction with LDA in THF (Scheme 7, entry b). Failure in these ring closure reactions has been attributed to inadequate car-... 

Reaction with potassium amide in liquid ammonia at - 33°C (Scheme 79). At -75°C. 

In the same manner, 3,3-ethylenedioxycyclopropcne was prepared from l-bromo-3-chloro-2,2-ethylenedioxypropanc, while 2-chloromethyl-2-halomethyl-l,3-dioxancs 2 w ere converted into the cyclopropenes 3 by reaction with potassium amide.Alternatively 2 (X = Cl) was converted directly into 1-sodiocyclopropene 4 by reaction with an excess of sodium amide in liquid ammonia.Trapping of 1-sodiocyclopropene 4 by other electrophiles is discussed in Section 4.2.1.1. 

In 6-fiuoro-2,3-di phenyl pyrido[2,3-0]pyrazine, the fluoro group may be exchanged for an amino substituent by reaction with potassium amide in liquid ammonia.34... 

AMMONIUM HYDROGEN SULFATE or AMMONIUM HYDROGEN SULPHATE (7783-20-2) Aqueous solution is a strong acid. Reacts with caustics, forming ammonia. Violent reaction with potassium chlorate. Hot material reacts with nitrates, nitrites, chlorates. Attacks metals. Incompatible with sulfuric acid, aliphatic amines, alkanolamines, amides, organic anhydrides, isocyanates, vinyl acetate, alkylene oxides, epichlorohydrin. Mixture with sodium hypochlorite forms unstable explosive nitrogen trichloride. 

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