[jtoy4eva]

i've tried constructing a detailed mechanism for this reaction

but still i am stuck and confused

ammonia is a base so it cannot donate a proton to the O on the pentanone
and i cannot find any relevant information on the ring opening and replacing oxgen with NH

I guess this is it for me...T_T

[sjb]

Maybe start with ammonia acting as a nucleophile, rather than a base, so you form the hemi-aminal, which then collapses to the amido-alcohol. Whilst amides aren't that basic, the fact you form a 5-membered ring if you then nucleophilically attack the carbon with the alcohol and condense out water may be enough to entropically drive the reaction, but I'm not 100% sure