Alkyl nitrate nitration of active methylene compounds. Nitration of 2‐substituted 2‐oxazolines

Abstract

Abstract2‐Alkyl‐ and 2‐aralkyl‐2‐oxazolines are readily converted to the corresponding α‐nitroalkyl‐ and α‐nitroaralkyl‐2‐oxazolines on treatment with an alkali metal amide such as potassium or sodium amide in liquid ammonia or with lithium diisopropylamide (LDA) in THF and an alkyl nitrate. Tertiary nitro compounds, such as 2‐(2‐nitro‐2‐propyl)‐4,4‐dimethyl‐2‐oxazoline (16) and 2‐(diphenylnitromethyl)‐4,4‐dimethyl‐2‐oxazoline (17) are obtained in good yield when the anions of 2‐(2‐propyl)‐4,4‐dimethyl‐2‐oxazoline (14) and of 2‐(diphenylmethyl)‐4,4‐dimethyl‐2‐oxazoline (23), generated by LDA are added to the nitrate in THF (inverse addition). The spectral data of the primary and secondary α‐nitroalkyl‐ and α‐nitroaralkyl‐2‐oxazolines reveal that they exist mostly in their dipolar structure. These compounds are readily converted to the corresponding α‐halonitro‐2‐oxazolines on treatment with potassium hypobromite or hypochlorite.