Title Page
Contents
LIST OF ABBREVIATIONS 11
ABSTRACT 12
I. Introduction 14
1.1. NMR Spectroscopy 14
1.2. Hyperpolarization 16
1.2.1. para-Hydrogen 16
1.2.2. SABRE 17
1.2.3. SABRE-SHEATH 18
II. Method 19
2.1. SABRE with PHOX derivatives 19
2.2. Hyperpolarization with amino acid methyl ester 21
2.2.1. SABRE with methylated amino acid 21
2.2.2. SABRE with hydrolysis of methylated amino acid 21
2.2.3. SABRE-SHEATH with methylated amino acid 21
2.3. Calculation of NMR polarization enhancement 23
III. Results and Discussion 24
3.1. SABRE with Iridium complex 24
3.1.1. Preparation of SABRE catalyst 24
3.1.2. Hyperpolarization of substrates 25
3.2. Hyperpolarization of methylated amino acids 28
3.2.1. Protection of amino acids 28
3.2.2. SABRE with methylated amino acids 31
3.2.3. SABRE with hydrolysis of methylated amino acid 35
3.2.4. SABRE-SHEATH with labeled amino acid methyl ester 36
IV. Conclusion 38
V. Experimental Section 39
5.1. General information 39
5.2. Reagent 40
5.3. Synthesis 43
5.4. Spectrum 52
5.5. SABRE results for PHOX derivatives 77
5.6. SABRE results for amino acid methyl ester 81
VI. Reference 84
국문요약 89
Table 1. The reaction of Iridium complex with PHOX derivative 25
Table 2. ¹H enhancement of nitrogen-containing compounds 27
Table 3. Esterification of amino acids with methanol in the presence of SOCl₂. 29
Table 4. Average ¹H enhancement of protons in each amino acid at the most... 34
Figure 1. The two allowed spin states for proton (a) and the spin-state energy... 14
Figure 2. Nuclear spin state populations for thermally polarized (left) and... 16
Figure 3. Spin state of hydrogen and ratio of para-hydrogen with temperature. 17
Figure 4. The structure of iridium catalysts containing PHOX derivatives (2a-c)... 20
Figure 5. Schematic diagram of home-built p-H₂ generator. 22
Figure 6. ¹H spectrum of normal (gray) and hyperpolarized glycine methyl ester... 31
Figure 7. ¹H spectrum of normal (gray) and hyperpolarized leucine methyl ester... 32
Figure 8. ¹H enhancement of proton in methylated glycine (a) and leucine (b) in... 32
Figure 9. ¹H spectrum of normal and hyperpolarization of hydrolyzed leucine... 35
Figure 10. ¹H spectrum of normal and hyperpolarization of hydrolyzed arginine... 36
Figure 11. ¹³C enhancement of arginine methyl ester (a) and leucine methyl ester (b). 37
Scheme 1. General SABRE reaction mechanism 18
Scheme 2. Protection of amino acids. 28
Equation 1. Calculation of ¹H polarization enhancement (ε). 23
Equation 2. Calculation of ¹³C polarization enhancement (ε). 23