Water Catalyzed Excited-State Proton Transfer Reactions in 7-Azaindole and its Analogues

Transcription

1 Supporting Information Water Catalyzed Excited-State Proton Transfer Reactions in 7-Azaindole and its Analogues Yu-Sin Wu, Huai-Ching Huang, Jiun-Yi Shen, Huan-Wei Tseng, Jr-Wei Ho, You-Hua Chen and Pi-Tai Chou* Department of Chemistry and Center for Emerging Material and Advanced Devices, ational Taiwan University, Taipei 10617, Taiwan These authors contributed equally to this work *To whom correspondence should be addressed: (P.-T. Chou) Contents 1. Excitation spectra for 7AI...S2 2. Synthesis and characterization s3 3. Spectroscopic and dynamic measurements..s6 4. Calculation of ph and H value......s7 5. Reference....S7 S1

2 1. Excitation spectra for 7AI. 1.0 ormalized Intensity Wavelength(nm) Figure S1. ormalized excitation spectra for 7-azaindole (7AI) in a room-temperature aqueous solution monitored at the normal emission band (400 nm, blue curve) and the tautomer emission band (550 nm, green curve). The concentration of aoh (aq) is 1.96 M and the ph is A normalized absorption spectrum of 7AI is also included for comparison (red curve). S2

3 2. Syntheses and characterizations. General Procedure for the Synthesis of the methyl ((7)-CH 3 ) tautomer compounds. The corresponding azaindole (1 eq.) and MeI (3 eq.) were dissolved in THF into a sealed bottle, then the mixture was heated to reflux for 24 h. After cooling, the solid was formed and filtered. Then, the solid was dissolved in water and washed three times with dichloromethan. The aqueous solution was adjusted ph to 12 with aoh (aq) and extracted by dichloromethane. The organic layer was dried over MgSO 4 and filtered. The organic layer was evaporation under reduced pressure and dried under vacuum. The methyl ((7)-CH 3 ) tautomer compound was obtained without further purification. 7-methyl-7H-pyrrolo[2,3-b]pyridine (7M7AI) : Follow the general procedure. Yield: 38%. 1 H MR (400 MHz, CDCl 3 ): δ 4.17 (s, 3H), 6.60 (d, J = 2.4 Hz, 1H), 6.72 (t, J = 7.2 Hz, 1H), 7.43 (d, J = 6.0 Hz, 1H), 7.82 (d, J = 2.4 Hz, 1H), 8.02 (d, J = 7.2 Hz, 1H). 13 C MR (100 MHz, CDCl 3 ): δ 39.7, 101.0, 108.5, 129.5, 129.6, 130.2, 144.7, FAB MS (m/z): 133 (M+H) +. 3,7-dimethyl-7H-pyrrolo[2,3-b]pyridine (7M3MAI) : Follow the general procedure. Yield: 45%. 1 H MR (400 MHz, CDCl 3 ): δ 2.35 (s, 3H), 4.24 (s, 3H), (m, 1H), 7.52 (d, J = 6.0 Hz, 1H), 7.60 S3

4 (s, 1H), 7.98 (d, J = 7.2 Hz, 1H). 13 C MR (100 MHz, CDCl 3 ): δ 9.6, 39.9, 107.9, 110.7, 128.7, 129.5, 130.2, 142.8, FAB MS (m/z): 147 (M+H) +. C H 3CAI THF, MeI Reflux, 24 h C 7M3CAI 7-methyl-7H-pyrrolo[2,3-b]pyridine-3-carbonitrile (7M3CAI) : Follow the general procedure. Yield: 32%. 1 H MR (400 MHz, CDCl 3 ): δ 4.33 (s, 3H), (m, 1H), 7.78 (d, J = 5.6 Hz, 1H), 8.21 (s, 1H), 8.24 (d, J = 7.6 Hz, 1H). 13 C MR (100 MHz, CDCl 3 ): δ 40.7, 84.9, 112.1, 116.6, 129.6, 131.6, 132.3, 148.8, FAB MS (m/z): 158 (M+H) +. 7-methyl-2-(trifluoromethyl)-7H-pyrrolo[2,3-b]pyridine (7M2CF 3 AI): Follow the general procedure. Yield: 30%. 1 H MR (400 MHz, CDCl 3 ): δ 4.31(s, 3H), (m, 2H), 7.72 (d, J = 6.0 Hz, 1H), 8.22 (d, J = 7.6 Hz, 1H). 13 C MR (100 MHz, CDCl 3 ): δ 40.2, 100.5, 110.1, 121.5, 124.1, 128.5, 132.8, 134.1, FAB MS (m/z): 201 (M+H) +. S4

5 1a Boc HAc Silica Gel / EA Reflux,18 h 1b H HAc THF, MeI Reflux, 24 h CO 2 H H 2 HCl (aq) Reflux,18 h HAc 7M(2,7-aza)Trp 1c Diethyl-2-((1H-pyrazolo[3,4-b]pyridin-3-yl)methyl)-2-acetamidomalonate (1b). Compound 1a (1 g) was dissolved in ethyl acetate and silica gel (50 g) was added and refluxed for 18h. The solution was allowed to cool down to room temperature. The silica gel in the solution was filtered and washed using ethyl acetate (5 100 ml). The filtrate was evaporated under reduced pressure and 1b was obtained as a white solid. Yield: 90%. 1 H MR (400 MHz, CDCl 3 ): δ 1.27 (t, J = 7.2 Hz, 6H), 1.88 (s, 3H), 4.05 (s, 2H), (m, 4H), 6.70 (s, 1H), 7.11 (dd, J = 8.0, 4.4 Hz, 1H), 7.98 (d, J = 8.0 Hz, 1H), 8.51 (d. J = 4.4 Hz, 1H), 11.2 (s, 1H). 13 C MR (100 MHz, CDCl 3 ): δ 13.9, 22.9, 30.0, 62.8, 66.4, 115.6, 116.6, 129.5, 140.5, 148.7, 151.9, 167.4, FAB MS (m/z): 349 (M+H) +. Diethyl-2-acetamido-2-((7-methyl-7H-pyrazolo[3,4-b]pyridin-3-yl)methyl)malonate (1c). Follow the general procedure. Yield: 15 %. 1 H MR (400 MHz, CDCl 3 ): δ 1.26 (t, J = 7.2 Hz, 6H), 1.87 (s, S5

6 3H), 4.08 (s, 2H), 4.27 (q, J = 7.2 Hz, 4H), 4.33 (s, 3H), (m, 1H), 6.96 (s, 1H), 7.79 (d, J = 6.8 Hz, 1H), 8.24 (d, J = 7.6 Hz, 1H). 13 C MR (100 MHz, CDCl 3 ): δ 13.7, 22.8, 30.3, 40.3, 62.4, 66.4, 109.3, 123.2, 134.7, 136.1, 143.4, 150.2, 167.4, FAB MS (m/z): 363 (M+H) +. 2-amino-3-(7-methyl-7H-pyrazolo[3,4-b]pyridin-3yl) propanoic acid (7M(2,7-aza)Trp): Compound 3c (0.89 g, 2.0 mmol) was dissolved in 12 M HCl and heated to reflux for 8 h. The reaction mixture was concentrated under reduced pressure to afford 7M(2,7-aza)Trp as a white solid in the HCl salt form. 1 H MR (400 MHz, D 2 O): δ 3.85 (d, J = 6.0 Hz, 2H), 4.44 (s, 3H), 4.68 (t, J = 6.0 Hz, 1H), (m, 1H), 8.81 (d, J = 6.0 Hz, 1H), 8.98 (d, J = 8.0 Hz, 1H). 13 C MR (100 MHz, D 2 O): δ 26.6, 42.6, 51.6, 117.7, 120.2, 140.9, 142.4, 144.6, 145.4, FAB MS (m/z): 221 (M+H) Spectroscopic and dynamic measurements. In this measurement, following the excitation at 268 nm (third harmonic generation of 805 nm), the fluorescence from a rotating sample cell was collected, focused, and frequency summed in a BBO crystal along with an interrogation gate pulse at designated delay time with respect to the pump pulse. A λ/2 waveplate was used to set the polarization of the pump pulses at the magic angle (54.7 ) with respect to the gate pulses to prevent the fluorescence anisotropy contributed by solute reorientation. Fluorescence up-conversion data were fitted to the sum of exponential functions convoluted with the instrument response function (IRF). The IRF was determined by monitoring the Raman scattering signal and its profile was fitted to a Gaussian function with a full width at half maximum of ~150 fs. S6

7 4. Calculation of ph and H value. When [H + ] or [OH - ] is less than 1M, we use the ph meter (CLEA PH500) to determine the ph value of the solution. When [OH - ] is greater than 1M, the ph value is calculated by the following equations: pk w = ph + poh 14 = ph + ( -log [aoh] ) ph = 14 + log[aoh] In dilute solution of acids or bases, the activity coefficient of ion approaches 1. However, the activity coefficient of ion is much deviated from 1 in concentrated solution. Therefore, we also provided the value of H calculated by Hammett acidity function to show the basicity for base solution. The value of H is taken from Q. Rev. Chem. Soc., 1966, 20, 511. S1 5. Reference : (S1). Rochester C.H. The Application of the Acidity Function Concept to Strongly Basic Media. Q. Rev. Chem. Soc., 1966, 20, S7