Epoxides with ammonia

Nakajima and coworkers have prepared seven new ortho- and meta-diaminotetrols, for example (121), by reaction of ammonia with epoxides such as (120), derived from i T-acetyl- conduramines (110). ... 

Nucleophilic ring opening of epoxides by ammonia (Section 16 12) The strained ring of an epoxide is opened on nucleo philic attack by ammonia and amines to give 3 ammo alcohols Azide ion also re acts with epoxides the products are p azido alcohols... 

Excellent yields can be obtained when the mixture of RC=CLi and the epoxide in ammonia is allowed to stand for 12 to 24 hours [2]. With sodium acetylides, there is some risk of subsequent attack of the acetylenic alcoholate on the epoxide, especially when the latter compound is used in excess. The reaction of acetylenic magnesium halides, RCsCMgX, with epoxides also leads to homopropargylic alcohols, but this is generally not recommended as a satisfactory method, as impure products are often obtained [62], Coordination of the epoxide-oxygen atom with the Lewis acid may give rise to a Sjql-like attack of RCaC on... 

Anderaaon 0 has determined pseudo finat-order rate constants for the reaction of exoees ammonia with a variety of epoxides, ranging from ethylene oxide itself to tefcramethylethylen oxide, and including also oyolohexene oxide, styrene oxide, and glyoidol. The least reactive substance studied, tetramethylethylenc oxide, was found to react 600 times more slowly than ethylene oxide. Curiously enough, on the other hand, glyoidol, styrene oxide, and ethylene oxide all roar ted at comparable rates. 

Ammonia is a nucleophile capable of reacting with epoxides. It attacks the less hindered carbon of the epoxide function. 

This compound cannot be prepared by reaction of ammonia with an epoxide, because in basic solution nucleophiles attack epoxides at the less hindered carbon, and therefore epoxide ring opening will give l-amino-2-methyl-2-propanol rather than 2-amino-2-methyl-l-propanol. 

Further support for Heck s suggestion that HCo(CO)4 reacts as an acid with epoxides was found by Takegami et al. (145), who pointed out that the relative reactivities of propylene oxide/epichlorohydrin is 30/1 for cobalt hydrocarbonyl. The same order of reactivity is shown to acids (propylene oxide/epichlorohydrin = 70 for perchloric acid) while the reactivity propylene oxide/epichlorohydrin for bases is in the reverse order (0.25 for ammonia). 

Amines usually react with epoxides at the less substituted carbon atom (Scheme4.73) [329, 330], With sterically demanding reaction partners these reactions will often proceed slowly or, as with tetraalkyl epoxides, not at all [252, 331]. Higher reaction rates can be achieved by increasing the concentration of the reactants, by using lithium amides as nucleophiles [332], or by catalysis with Lewis acids [252, 333] or Bronsted acids [334]. Ammonia can also be alkylated by 2,3-dialkyl epoxides (80 °C, 15-60 h [335]). Hydroxymethyl epoxides (but not alkoxymethyl epoxides) can be activated toward nucleophilic attack by amines by use of stoichiometric amounts of Ti(OiPr)4 [336] (third example, Scheme4.73). 

The reaction between epoxides and ammonia (or ammonium hydroxide) is a general and useful method for the preparation of (3-hydroxyamines. With epoxide derived from terminal alkenes, the reaction with ammonia gives largely the primary amine, but secondary and tertiary amine products are possible from the appropriate epoxide. The reaction of 121 with ammonium hydroxide with microwave irradiation, for example, gave 122. Ethanolamines, which are useful solvents... 

Opening the epoxide with a nitrogen nucleophile makes one isomer. At least the alkene is symmetrical so it doesn t matter which end of the epoxide is attacked by the nucleophile. We have chosen azide ion (N ) as the nucleophile. Ammonia wdll also do as, although it can react repeatedly, it usually behaves itself with epoxides. You were not asked to make both diastereoisomers, so we can stop there. 

One of die most popular reactions in organic chemistry is dissolving metal reductions [1-3], Two systems are frequently used - sodium dissolved in ammonia with alcohol and lithium dissolved in alkylamines [4]. Although calcium is seldom used, it has been successfully applied to the reduction of a variety of compounds and functional groups [5], including aromatic hydrocarbons, carbon-carbon double and triple bonds, benzyl ethers, allyl ethers, epoxides, esters, aliphatic nitriles, dithianes, als well as thiophenyl and sulfonyl groups. 

Preparation. 2-Hydroxyethylphosphines are conveniently prepared from red phosphorus, via reduction with Na in f-BuOH and reaction of the resulting NaPH2 with epoxides in liquid ammonia. ... 

Quaternary ammonium hydroxides are strong bases. Amines react with epoxides in the manner of ammonia ... 

Ammonia and amines react with epoxides with the same stereospecificity as anionic nucleophiles. Draw a sawhorse or Newman projection formula for the product of the reaction shown, clearly showing the stereochemistry at both chirality centers. What are the Cahn-lngold-Prelog R,S descriptors for these chirality centers in the reactant and the product ... 

The hydrogenolyaia of cyclopropane rings (C—C bond cleavage) has been described on p, 105. In syntheses of complex molecules reductive cleavage of alcohols, epoxides, and enol ethers of 5-keto esters are the most important examples, and some selectivity rules will be given. Primary alcohols are converted into tosylates much faster than secondary alcohols. The tosylate group is substituted by hydrogen upon treatment with LiAlH (W. Zorbach, 1961). Epoxides are also easily opened by LiAlH. The hydride ion attacks the less hindered carbon atom of the epoxide (H.B. Henhest, 1956). The reduction of sterically hindered enol ethers of 9-keto esters with lithium in ammonia leads to the a,/S-unsaturated ester and subsequently to the saturated ester in reasonable yields (R.M. Coates, 1970). Tributyltin hydride reduces halides to hydrocarbons stereoselectively in a free-radical chain reaction (L.W. Menapace, 1964) and reacts only slowly with C 0 and C—C double bonds (W.T. Brady, 1970 H.G. Kuivila, 1968). 

Does the NMR spectrum shown in Figure 22 10 correspond to that of 1 amino 2 methyl 2 propanol or to 2 ammo 2 methyl 1 propanoD Could this compound be prepared by reaction of an epoxide with ammonia" ... 

Telomerization Reactions. Butadiene can react readily with a number of chain-transfer agents to undergo telomerization reactions. The more often studied reagents are carbon dioxide (167—178), water (179—181), ammonia (182), alcohols (183—185), amines (186), acetic acid (187), water and CO2 (188), ammonia and CO2 (189), epoxide and CO2 (190), mercaptans (191), and other systems (171). These reactions have been widely studied and used in making unsaturated lactones, alcohols, amines, ethers, esters, and many other compounds. 

The chemical resistance of PTFE is exceptional. There are no solvents and it is attacked at room temperature only by molten alkali metals and in some cases by fluorine. Treatment with a solution of sodium metal in liquid ammonia will sufficiently alter the surface of a PTFE sample to enable it to be cemented to other materials using epoxide resin adhesives. 

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