Synthesis, Characterization, and Structure of Some 1,4‐Disubstituted Cyclopenta[d][1,2]oxazines

Oxazine‐based chemistry offers an alternative to thiophene and pyrrole semiconductors and has been largely unexplored for electronics applications. Discrete monomers or oxazine polymers could serve as an efficient hole carrier for novel devices. A series of 1,4‐disubstituted cyclopenta[d][1,2]oxazines (R = tolyl, p‐nitrophenyl, t‐buytl, furyl, and 5‐methylthienyl) were isolated via ring closure with hydroxylamine from a 1,2‐acylcyclopentadiene precursor. The target oxazines were characterized by NMR and IR spectroscopy and direct analysis in real time (DART) MS. Single‐crystal x‐ray structure determination confirmed the identity of the tolyl oxazine, which shows a face‐to‐face stacking pattern of the heterocyclic rings.