Methylamine, reaction with lactones

Solid lactones or cyclic carbonates form linear hydroxy amides upon reaction with gaseous ammonia, methylamine, or ethylamine. For example, the compounds 277a-c and (ketonized) 279a-c are quantitatively formed at 0 °C and room temperature, respectively, without melting [12] (Scheme 39). 

The Fischer cyclization of phenylhydrazones of structure (18) gives rise to the carbinolamine-lactones (19). Reaction with methylamine, followed by reduction, then affords a short synthesis of esermethole (20a) and eserethole (20b) (Scheme... 

The y-lactone ring in cardenolides has also been modified.Digitoxigenin (520) or isodigitoxigenin (521) were directly transformed into a mixture of isomeric lactams (523) by treatment with ammonia or methylamine. The lactol-amide intermediate (522) could be isolated when the reaction was performed at room temperature, and this was transformed to the lactam (523) by dilute acid. Gitoxigenin (524) reacted in an analogous way to afford the related lactams (525). From these experiments, it appears that the reaction with cardenolides gives... 

Just as amines react with esters to form amides, lactones react with amines to give lactams or are opened to give amino acid derivatives directly. When P-propiolactone (2.20) reacted with ammonia, for example, 3-aniinopropanamide (2.2Ia) was obtained. 2 Similar reaction with methylamine gaveno2.2/h but rather a 97% yield of 3-aminopropanoic acid, 2.22. Dimethylamine, however, converted 2.20 to 2.2Ic in 79% yield, along with 13% of 2.22.12... 

Further transformation of the ester group in 126 was easily achieved. Thus, 126 with methylamine and 2-dimethylaminoethylamine gave the lactams 127 a and 127b. Reaction of the free acid derived from 126 with thionyl chloride yielded the lactone 127 c (Scheme 42) [7m, 60 a]. 

The reaction of 2-amino-4,5-dihydro-3-furancarboxylic esters (51) with amines appears interesting85. In contrast to the structure assigned earlier86-88, the reaction products have been later identified as 1,1-enediamines attached to a lactone moiety85. Thus, substrate 51 reacts with methylamine to give acyclic 1,1-enediamines 52 with an approximate E/Z ratio of 40 60. The reaction involves 4,5-dihydrofuran ring-opening and lactone-formation steps (Scheme 3). In the case of ethylenediamine and 1,3-diaminopropane, the reaction of 51 leads to the formation of cyclic 1,1-enediamine... 

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