Epoxides, reaction with ammonia

Other examples of related reactions have been summarized,24 and the cleavage of sugar epoxide derivatives with ammonia has been discussed in detail.26... 

Reaction of C-5 activated pentonolactones 13) and of 2,7-diactivated heptonolactones lib, 13) with ammonia gave in both cases 6-membered imino sugars by similar formation of epoxide intermediates (Scheme 4). The 6-bromo-2,6-dideoxy-D-anz6z> 0-hexono- 1,4-lactone gave by reaction with ammonia the 7-membered lactam 14) (Scheme 4). 

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... 

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" ... 

A rather complex microwave-assisted ring-opening of chiral difluorinated epoxy-cyclooctenones has been studied by Percy and coworkers (Scheme 6.131) [265]. The epoxide resisted conventional hydrolysis, but reacted smoothly in basic aqueous media (ammonia or N-methylimidazole) under microwave irradiation at 100 °C for 10 min to afford unique hemiacetals and hemiaminals in good yields. Other nitrogen nucleophiles, such as sodium azide or imidazole, failed to trigger the reaction. The reaction with sodium hydroxide led to much poorer conversion of the starting material. 

Ring cleavage of acetylenic epoxides may be illustrated by the reactions of the substituted 1,2-epoxy-3-butyne derivatives represented in Eq. (023) with ammonia, ethylamine, diethylamjne, and others.1845 1316, isao... 

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. 

Cyclopropen-1-yl sodium derivatives are also readily prepared. Thus reaction of cyclopropene with one equivalent of sodium amide in liquid ammonia leads to 1-sodiocyclopropene which is alkylated by haloalkanes 77,78 reacts with ketones to produce tertiary alcohols and opens epoxides to produce 2-cyclopropenyl-ethanols in moderate to good yields79). Moreover, on reaction with two equivalents of base followed by haloalkane, 1,2-dialkylated species are obtained sequential reactions can also be used to produce unsymmetrically substituted cyclopropenes78). Reaction with a deficiency of sodium amide can also cause addition of the cyclopro-penyl anion to unreacted cyclopropene, leading to products derived from the 2-cyclo-propylcydopropen-l-yl anion and to 1,2-dicyclopropylcyclopropene 77). 

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