Found in California petr: Hackmann et al., Rec. Trav. Chim. 62, 229 (1943). Best prepd from pyridine by treatment with acetic anhydride and zinc: Dohrn, Horsters, DE 390333 (1924 to Schering); Wibaut, Arens, Rec. Trav. Chim. 60, 119 (1941); Frank, Smith, Org. Synth. 27, 38 (1947). Using iron powder: Tenenbaum, Fand, US 2712019 (1955 to Nepera Chem.).