Electronic Supplementary Material (ESI) for RSC Advances. This journal is © The Royal Society of Chemistry 2014

Conformationally restricted glutamic acid

analogues: stereoisomers of

1-aminospiro[3.3]heptane-1,6-dicarboxylic acid

Anton V. Chernykh, a, b Dmytro S. Radchenko, a, c Oleksandr O. Grygorenko, c

Dmitriy M. Volochnyuk, b Svitlana V. Shishkina, d Oleg V. Shishkin d and Igor V. Komarov c, *

a Enamine Ltd., Alexandra Matrosova Street 23, 01103,

b Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanska 5, Kyiv

02660, Ukraine

c National University of Kyiv, Volodymyrska Street 60, Kyiv 01601, Ukraine

E-mail: [email protected]

d STC “Institute for Single Crystals”, National Academy of Sciences of Ukraine, 60 Lenina ave.,

61001 Kharkiv, Ukraine

S1

Table of contents.

1. 1H NMR spectrum of the compound 8 S5

2. 13 C NMR spectrum of the compound 8 S6

3. 1H NMR spectrum of the compound 13 S7

4. 13 C NMR spectrum of the compound 13 S8

5. 31 P NMR spectrum of the compound 13 S9

6. 1H NMR spectrum of the compound 15 S10

7. 13 C NMR spectrum of the compound 15 S11

8. 1H NMR spectrum of the compound 9 S12

9. 13 C NMR spectrum of the compound 9 S13

10. 1H NMR spectrum of the compound 11a S14

11. 13 C NMR spectrum of the compound 11a S15

12. NOE spectrum of the compound 11a S16

13. HMBC spectrum of the compound 11a S17

14. 1H-1H COSY spectrum of the compound 11a S18

15. NOESY spectrum of the compound 11a S19

16. NOESY spectrum of the compound 11a (fragment) S20

17. 1H NMR spectrum of the compound 11b S21

18. 13 C NMR spectrum of the compound 11b S22

19. NOE spectrum of the compound 11b S23

20. 1H-1H COSY spectrum of the compound 11b S24

21. HMBC spectrum of the compound 11b S25

22. NOESY spectrum of the compound 11b S26

23. NOESY spectrum of the compound 11b (fragment) S27

24. 1H NMR spectrum of the compound 16a S28

25. 13 C NMR spectrum of the compound 16a S29

S2

26. 1H NMR spectrum of the compound 16b S30

27. 13 C NMR spectrum of the compound 16b S31

28. 1H NMR spectrum of the compound 16c S32

29. 13 C NMR spectrum of the compound 16c S33

30. 1H NMR spectrum of the compound 16d S34

31. 13 C NMR spectrum of the compound 16d S35

32. 1H NMR spectrum of the compound 1a ⋅HCl S36

33. 13 C NMR spectrum of the compound 1a ⋅HCl S37

34. 1H NMR spectrum of the compound 1b ⋅HCl S38

35. 13 C NMR spectrum of the compound 1b ⋅HCl S39

36. 1H NMR spectrum of the compound 1c ⋅HCl S40

37. 13 C NMR spectrum of the compound 1c ⋅HCl S41

38. 1H NMR spectrum of the compound 1d ⋅HCl S42

39. 13 C NMR spectrum of the compound 1d ⋅HCl S43

40. 1H NMR spectrum of the compound 18a S44

41. 13 C NMR spectrum of the compound 18a S45

42. 1H NMR spectrum of the compound 18b S46

43. 13 C NMR spectrum of the compound 18b S47

44. 1H NMR spectrum of the compound 18c S48

45. 13 C NMR spectrum of the compound 18c S49

46. 1H NMR spectrum of the compound 18d S50

47. 13 C NMR spectrum of the compound 18d S51

48. 13 C DEPT spectrum of the compound 18d S52

49. 1H NMR spectrum of the compound 19 c S53

50. 13 C NMR spectrum of the compound 19 c S54

51. Stereochemical assignments of 1a -d S55

S3

52. Table S1. Crystallographic data and experimental parameters S56

for the compound 13 and 18a-c

53. ORTEP diagrams of the compounds 18a–c S57

S4

1H NMR spectrum of the compound 8

S5

13С NMR spectrum of the compound 8

S6

1H NMR spectrum of the compound 13

S7

13С NMR spectrum of the compound 13

S8

31 P NMR spectrum of the compound 13

S9

1H NMR spectrum of the compound 15

S10

13C NMR spectrum of the compound 15

S11

1H NMR spectrum of the compound 9

S12

13С NMR spectrum of the compound 9

S13

1H NMR spectrum of the compound 11a

S14

13C NMR spectrum of the compound 11a

S15

NOE spectrum of the compound 11a

S16

HSQC spectrum of the compound 11a

S17

1H-1H COSY spectrum of the compound 11a

S18

NOESY spectrum of the compound 11a

S19

NOESY spectrum of the compound 11a (fragment)

S20

1H NMR spectrum of the compound 11b

S21

13C NMR spectrum of the compound 11b

S22

NOE spectrum of the compound 11b

S23

1H-1H COSY spectrum of the compound 11b

S24

HSQC spectrum of the compound 11b

S25

NOESY spectrum of the compound 11b

S26

NOESY spectrum of the compound 11b (fragment)

S27

1H NMR spectrum of the compound 16a

S28

13C NMR spectrum of the compound 16a

S29

1H NMR spectrum of the compound 16b

S30

13C NMR spectrum of the compound 16b

S31

1H NMR spectrum of the compound 16c

S32

13C NMR spectrum of the compound 16c

S33

1H NMR spectrum of the compound 16d

S34

13C NMR spectrum of the compound 16d

S35

1H NMR spectrum of the compound 1a ⋅HCl

S36

13C NMR spectrum of the compound 1a ⋅HCl

S37

1H NMR spectrum of the compound 1b⋅HCl

S38

13C NMR spectrum of the compound 1b⋅HCl

S39

1H NMR spectrum of the compound 1c⋅HCl

S40

13C NMR spectrum of the compound 1c⋅HCl

S41

1H NMR spectrum of the compound 1d⋅HCl

S42

13C NMR spectrum of the compound 1d⋅HCl

S43

1H NMR spectrum of the compound 18a

S44

13C NMR spectrum of the compound 18a

S45

1H NMR spectrum of the compound 18b

S46

13C NMR spectrum of the compound 18b

S47

1H NMR spectrum of the compound 18c

S48

13C NMR spectrum of the compound 18c

S49

1H NMR spectrum of the compound 18d

S50

13C NMR spectrum of the compound 18d

S51

13C DEPT spectrum of the compound 18d

S52

1H NMR spectrum of the compound 19c

S53

13C NMR spectrum of the compound 19c

S54

Stereochemical assignments of 1a-d

The stereochemical assignment of the final compounds 1a-d was done basing on several experiments: 1D- and 2D-NOESY for compounds 11a ,b (see above) and X-ray diffractional studies of three purposely synthesized compounds 18a -c.

Before performing the NOE studies, we assigned the NMR signals in the spectra of 11a ,b using APT, HSQC, H,H-COSY experiments (see the spectra above). The H2 proton (which gives NMR signal at 3.15 ppm for 11a, 3.08 ppm for 11b ), assigned reliably by its correlation with the C2 in the HSQC (the only tertiary carbon atom, 32.8 ppm for 11a, 31.9 ppm for 11b) was irradiated; NOE effect was observed for the proton with the chemical shift 2.54 ppm for 11a and 2.19-2.34 ppm for 11b . At the same time, strong NOE correlation was observed in the 2D-NOESY spectra for H7 (1.97 ppm (11 а) and 2.11 ppm ( 11b)): with the signals H1b in 11a (2.33 ppm) and H3b in 11b (2.19-2.34 ppm). From these data we concluded that signals at 2.54 ppm ( 11 а) and 2.63-2.77 ppm ( 11b) correspond to Н1а and Н3а. Hence, the keto-ester 11a is the trans -isomer, because its H2 proton reveals strong NOE with Н1а and Н3а. Compound 11b is the cis -isomer, because its H2 proton shows strong NOE with Н1b and Н3b.

The crystallographic data, experimental parameters and CCDB deposition numbers are listed in Table S1. ORTEP diagrams of the compounds 18a–c illustrate the absolute configuration of the stereocenters in these compounds.

Ideally, X-Ray analysis of all the four derivatives 18a -d would give us enough information regarding the stereochemistry of 1a -d, because compounds 16a -d bear chiral auxiliary with the defined absolute configuration and transformed both into 1a -d and 18a -d without racemization at the stereocenters. However, compound 18d did not give crystals suitable for the X-Ray study. Its absolute stereoconfiguration was deduced using the following reasoning. Compound 18d is the only diastereomer of the four possible (the chiral auxiliary group was derived from the S-α-phenylglycinol for all the diastereomers); its absolute configuration at one of the stereocenter C2 (2 S) should be the same as in its precursor 11b , determined by 1D- and 2D-NOESY experiments. The other stereocenter C5 must have the stereoconfiguration reverse to that in its diastereomer 18c , thus, 5 S.

S55

Table S1 Crystallographic data and experimental parameters for the compound 13 and 18a–c

Parameter 13 18a 18b 18c a, Å 8.9199(4) 6.0940(5) 6.1255(6) 10.260(3) b, Å 18.9724(8) 15.418(2) 11.218(1) 5.820(2) c, Å 17.167(1) 17.637(2) 24.188(2) 14.060(4) α, deg 90.0 90.0 90.0 90.0 β, deg 100.522(5) 90.0 90.0 98.37(3) γ, deg 90.0 90.0 90.0 90.0 V, Å 3 2856.4(3) 1657.1(3) 1662.1(3) 830.6(5) T, K 293(2) 293(2) 293(2) 293(2) F(000) 1132 672 672 336 Crystal system Monoclinic Rhombic Rhombic Monoclinic

Space group P21/n Р212121 Р212121 Р21 Z 2 4 4 2 µ, mm -1 0.307 0.089 0.089 0.089 3 dcalc , g/cm 1.256 1.264 1.260 1.261

2Θmax , deg 50 60 60 60 Reflection measured 19720 8562 13719 7469 Reflections independent 5018 4455 4755 4370

Rint 0.023 0.071 0.102 0.155 Reflections with F>4 σ(F) 3827 1524 1883 836

R1 0.098 0.048 0.055 0.066

wR 2 0.285 0.064 0.084 0.159 S 1.227 0.793 0.840 0.696 CCDC deposition number 962474 962475 962476 962477

S56

ORTEP diagrams of the compounds 18a–c

18a 18b 18c

S57