Complete Structure Assignment of Azathioprine as a Proton-Deficient Nucleic Acid Analogue Using 1H-13C Long-Range Heteronuclear Single Quantum Multiple Bond Correlation.

Abstract

In this Note, the successful structural assignment of a proton-deficient nucleic acid analogue using the 1H-13C long-range heteronuclear single quantum multiple bond correlation (LR-HSQMBC) technique is described. LR-HSQMBC is a 2D NMR technique for the sensitive detection of weak C-H spin couplings. The immunosuppressant drug, azathioprine, served as the target compound. The LR-HSQMBC measurements revealed the existence of covalent bonds between the purine and imidazole rings based on observations of 5JCH and 6JCH with good sensitivity.