... Keywords. Nuclear Magnetic Resonance (NMR) Data Chemical Shifts and Coupling Constants for Hydrogen-1. Part 2: Heterocycles. ... Kay, IT, Punja, N.: J. Chem. Soc. (C) (1970) 2409. 70L'ab. L'abbé, G., Hassner, A.: J. Heterocyclic Chem.7 (1970) 361. 70Lan. ...