Abstract Alkylation of 5-substituted ethyl 5-methyl-2-oxotetrahydrofuran-3-carboxylates with alkyl halides in the presence of sodium ethoxide gave the corresponding 3-alkyl derivatives which were converted into 3, 5-substituted 5-methyl-N-(4-nitrophenyl)-2-oxotetrahydrofuran- 3-carboxamides and 5-methyltetrahydrofuran-2-ones. Reactions of the latter with hydrazine hydrate led to the formation of 4-hydroxypentanoic acid hydrazides which were treated ...