Abstract
A highly functionalized 9,9-disubstituted (phenylethynyl)-fluorene-appended N-methyl-7-azaindole derivatives has been synthesized from various fluorene propargylic alcohols and substituted-7-azaindoles using BF3OEt2 as a catalyst. The scope of the reaction was demonstrated by selecting a range of fluorene propargylic alcohols and substituting 7-azaindoles. A plausible reaction mechanism for forming title compounds via propargylic carbocation is postulated. The synthetic transformation of the products has been demonstrated by the Suzuki coupling and Click reaction. The Suzuki coupled compounds 5a–5e were evaluated for photophysical properties such as absorption, solvatochromism, emission, and Stokes shift and found blue emissive in nature.
Introduction
7-Azaindoles substituted at 3- or 5-positions have been identified as an important nitrogen heterocycle that possesses various biological activities and are used for the treatment of various diseases.1 For example, variolin B (I) isolated from an extremely rare Antarctic sponge is a promising anti-cancer agent,2 PLX5622 (II), a brain-penetrant CSF1R inhibitor, has been used in Alzheimer’s disease (AD),3 and pimodivir (III)4 and AZD6738 (IV) are a potent and selective ATR kinase inhibitor.25 On the other hand, fluorene-based compounds (V–VII) are essential structural frameworks in natural products,5 biological activity,6 light-emitting devices,7 solar cells, and8 optoelectronics9 (Figure 1). A number of reports are available for the preparation of 9,9-disubstituted fluorenes.10 Thus, developing synthetic methods for the hybrid 7-azaindole and fluorene-based compounds is highly warranted. The propargylic alcohols and their derivatives are extremely useful synthons for organic synthesis.11 Various propargylic alcohols are highly reactive with Lewis acid reagents12 and undergo nucleophilic substitution reactions with various nucleophiles to produce diverse and functionalized products.13−18 The synthesis of 3,4-dihydrocyclopenta[b]indole and 1,4-dihydrocyclopenta[b]indole and propargylic alcohol in the presence of different catalysts are known.19 We have been working on the chemistry of fluorene propargylic alcohol and diverse nucleophiles under Lewis acid conditions.20 The reaction of substituted phenyl propargylic alcohol such as 9-(phenylethynyl)-9H-fluoren-9-ol with an N-methyl-7-azaindole nucleophile is unknown. Thus, we explored the reaction of substituted 9-(phenylethynyl)-9H-fluoren-9-ol with many 7-azaindoles using BF3·Et2O as a Lewis acid catalyst and is reported.
Figure 1.
Biologically important molecules containing 7-azaindole and a 9,9-disubstitutedfluorene-based core structure.
In addition, the biphenyl-fluorene-7-azaindole hybrid products thus obtained via Suzuki coupling reaction were evaluated for photophysical properties and found to be blue emissive materials. The details of the study are presented in this manuscript.
Results and Discussion
Our initial study was focused on the reaction of fluorene propargylic alcohol 1a and N-methyl-5-bromo-7-azaindole 2a in the presence of 0.2 equiv of BF3·OEt2 in dichloromethane at 45 °C for 45 min. The reaction afforded the compound, namely, 1-methyl-3-(9-(phenylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b] pyridine 3a in 53% yield (Table 1, entry 1). The structure of compound 3a was established by spectroscopic methods such as 1H NMR, 13C NMR, DEPT-135, and HRMS (see the Supporting Information, Figures S5–S9), and the representative product structure 3b was established by single-crystal XRD analysis21 (Figure 2).
Table 1. Optimization of Synthesis of Compound 3a.
| entry | catalyst | solvent | catalyst (equiv) | time (min) | % yield of 3aa |
|---|---|---|---|---|---|
| 1 | BF3·OEt2 | DCM | 0.2 | 45 | 53 |
| 2 | BF3·OEt2 | DCM | 0.6 | 30 | 61 |
| 3 | BF3·OEt2 | DCM | 1 | 10 | 83b |
| 4 | BF3·OEt2 | DCM | 1.2 | 10 | 78 |
| 5 | BF3·OEt2 | DCM | 1 | 1 h | 75 |
| 6 | BF3·OEt2 | DCM | 1 | 3 h | 42c |
| 7 | BF3·OEt2 | DCE | 1 | 10 | 60 |
| 8 | BF3·OEt2 | ACN | 1 | 30 | 75 |
| 9 | BF3·OEt2 | MeOH | 1 | 10 | 41 |
| 10 | BF3·OEt2 | toluene | 1 | 10 | 35 |
| 11 | FeCl3 | DCM | 1 | 60 | 25 |
| 12 | InBr3 | DCM | 1 | 45 | 59 |
| 13 | In(OTf)3 | DCM | 1 | 15 | 43 |
| 14 | Cu(OTf)3 | DCM | 1 | 20 | 46 |
| 15 | HOTf | DCE | 1 | 10 | 44 |
Isolated yield after column purification.
Optimized condition.
Reaction was done at RT.
Figure 2.
ORTEP diagram of compound 3b (CCDC 2133015) showing atom labeling drawn at a 50% probability level.
To improve the yield of compound 3a, an optimization study was conducted by varying the reaction parameters such as Lewis acids (LA), solvent, equivalent of catalysts, and reaction time. Decreasing the mole equivalent of catalyst did not improve the yield and took more than 10 min to complete the reaction (Table 1, entries 1 and 2). However, the reaction of 1a with 1 equiv of substituted 7-azaindole 2a and BF3·OEt2 in 2 mL of DCM at 45 °C (Table 1, entry 3) was completed in 10 min to afford compound 3a in 83% yield and later found as the optimized condition. Increasing the mole equivalent of the catalyst did not improve the yield (Table 1, entry 4). When the reaction time was extended to 1 h, it showed no improvement in the yield (entry 5). The reaction was carried out at room temperature for 3 h using 1 equiv of BF3·OEt2 and provided only 42% of the yield of the desired product (Table1, entry 6). A change of solvents, such as DCE (1,2-Dichloroethane), ACN (acetonitrile), CH3OH (methanol), and toluene, did not improve the yield (Table 1, entries 7–10). Of all solvents tested, DCM (dichloromethane) was the most effective solvent to produce the desired compound 3a. Next, we screened the catalyst using different Lewis acids, such as FeCl3, which showed no remarkable improvement in the reaction yield (Table 1, entry 11). In InBr3, some improvement in the yield was observed (Table 1, entry 12). Then, we continued the reaction by using catalysts like In(OTf)3, Cu(OTf)3, and HOTf and afforded compound 3a in lower yield (Table 1, entries 13–15). Based on these results, we found that BF3·OEt2 is the most effective LA for the formation of compound 3a.
Having established an optimal protocol, we next investigated the generality and scope of the transformation utilizing a number of propargylic alcohols 1a–1k and substituted 7-azaindoles 2a–2f (Scheme 1).
Scheme 1. Synthesis of 3-Alkylated 7-Aza-indoles (3a–3x).
As illustrated in Figures 3 and 4, the under-optimized reaction conditions described above are effective for the transformation of a number of propargylic alcohols 1a–1k, and substituted 7-azaindoles 2a–2f produced corresponding 3-alkylated 7-azaindoles 3a–3x in good-to-excellent yields (Table 2). Thus, the fluorene propargylic alcohol 1a reacted with substituted 7-azaindoles 2a, 2b, and 2e–2f provided indole derivatives 3a–3d in good yields, and the best yield was found for product 3a (Table 2, entries 1–4). The methyl substitution fluorene propargylic alcohol 1b reacted with substituted 7-azaindole 2a and 2c–2f provided 7-azaindole derivatives 3e–3i (Table 2, entries 5–9). The methyl substitution on the meta position 1c was chosen to react with azaindole 2a to provide corresponding product 3j in 76% yield (entry 10). Then, we examined the reaction of substituted 7-azaindoles 2a, 2b, and 2e with different ethyl and n-butyl-substituted propargylic alcohols 1d and 1e and furnished corresponding products 3k–3m and 3n in 69, 60, 72, and 70% yields, respectively (entries 11–14). Then, the reaction was carried out with bromo-substituted propargylic alcohol 1f with substituted 7-azaindoles 2a and 2c–2d, and the respective products were formed 3o–3q in 75, 71, and 82% yields, respectively (entries 15–17). The propargylic alcohol bearing −OMe substitution 1g with 2e afforded product 3r in 70% yield (entry 18). The reaction was further demonstrated by the propargylic alcohol 1h bearing 4-methoxy and 2-methyl groups and provided the corresponding product 3s in 67% yield (entry 19). In addition, the propargylic alcohol having mono bromo substitution 1i and 1j also generated the respective compounds 3t–3w in 72, 42, 73, and 65% yields, respectively (Table 2, entries 20–23). The 2,7-dibromo-9H-fluorene propargylic alcohol 1k with 5-bromo-N-methyl-7-azaindole 2b afforded compound 3x in 44% yield (Table 2, entry 24).
Figure 3.
Various fluorene propargylic alcohols 1a–1g and 7-azaindoles 2a–2d.
Figure 4.
Synthesized compounds 3a–3x.
Table 2. Scope of the Reactiona.
| entry | propargylic alcohol 1 | 7-azaindole 2 | product 3 | % yieldb |
|---|---|---|---|---|
| 1 | 1a | 2b | 3a | 83 |
| 2 | 1a | 2a | 3b | 73 |
| 3 | 1a | 2c | 3c | 64 |
| 4 | 1a | 2f | 3d | 39 |
| 5 | 1b | 2a | 3e | 77 |
| 6 | 1b | 2b | 3f | 79 |
| 7 | 1b | 2d | 3g | 56 |
| 8 | 1b | 2f | 3h | 76 |
| 9 | 1b | 2e | 3i | 78 |
| 10 | 1c | 2b | 3j | 76 |
| 11 | 1d | 2a | 3k | 72 |
| 12 | 1d | 2b | 3l | 69 |
| 13 | 1d | 2c | 3m | 60 |
| 14 | 1e | 2b | 3n | 70 |
| 15 | 1f | 2a | 3o | 82 |
| 16 | 1f | 2b | 3p | 75 |
| 17 | 1f | 2d | 3q | 71 |
| 18 | 1g | 2a | 3r | 70 |
| 19 | 1h | 2d | 3s | 67 |
| 20 | 1i | 2a | 3t | 73 |
| 21 | 1i | 2b | 3u | 72 |
| 22 | 1i | 2d | 3v | 42 |
| 23 | 1j | 2b | 3w | 65 |
| 24 | 1k | 2b | 3x | 44 |
All the reactions were carried out using 1 equiv of BF3·OEt2 and 3 mL of DCM at 45 °C for 10 min.
Isolated yield.
Based on the structure of products, a plausible mechanism postulated for the formation of product 3 is provided in Scheme 2. Accordingly, at first, the propargylic alcohol 1a reacts with BF3·OEt2, which forms an electron-deficient alkyne carbocation A. The reaction followed by a nucleophilic attack of N-methyl-7-azaindole onto the carbocation produces the observed 3-alkylated substituted 7-azaindoles 3.
Scheme 2. Plausible Mechanism for the Formation of 3.
To demonstrate the synthetic utility of products thus obtained, the Suzuki coupling22 of product 3 having halogen substitution was demonstrated (Scheme 3). Thus, a reaction between 3 and aryl boronic acids 4a–4d using Pd(dppf)Cl2·DCM as the catalyst and K2CO3 as the base in a dioxane:MeOH (3:1) solvent system was microwave (MWs) irradiated (100 W) for 10 min. The reaction afforded biaryl-tethered compounds 5a–5e in very good combined yield (Table 3). Spectroscopic methods established the structure of the products.
Scheme 3. Synthesis of Biaryl Derivatives 5a–5e via Suzuki Coupling.
Table 3. Synthetic Transformation of 3 via Suzuki Coupling Reaction.
| entry | compound 3 (equiv) | boronic acid 4 (equiv) | product 5 | % yield |
|---|---|---|---|---|
| 1 | 3a(1) | 4a(1) | 5a | 60 |
| 2 | 3f(1) | 4a(1) | 5b | 40 |
| 3 | 3j(1) | 4b(1) | 5c | 67 |
| 4 | 3p(1) | 4c(2)a | 5d | 85 |
| 5 | 3u(1) | 4d(2)a | 5e | 58 |
2 equiv of boronic acid.
The further synthetic transformation was achieved through the Click reaction23 of N-propargylated derivative 3i with 1 equiv of each BnBr, NaN3, and Cu(I) catalyst and Et3N as a base to give rise to triazole derivative 6 in 60% yield (Scheme 4).
Scheme 4. Synthetic Transformation of 3i via “Click” Reaction.
Photophysical Studies
The 7-azaindole and their derivatives displayed significant photophysical properties. They were based on the luminescent properties of many materials applications that have been studied.24 Notably, the 7-azaindole emits a weak π*−π transition-based fluorescence, with λmax 350–360 nm in solution and the solid state. At the same time, its anion is a bright blue luminophore in solution and the solid state.24 Encouraged by this property, our final compounds 5a–5e possess a 7-azaindole, fluorene, aryl propargyl, and biaryl core group system that envisaged us to probe their photophysical properties. Based on the structural perspective, compound 5e was selected to evaluate photophysical properties. Thus, the UV absorption and emission spectrum for compound 5e in ACN showed two absorption maxima, measured at 285 and 308 nm, and emission maxima at 428 nm, observed in the blue region, respectively (Figure 5). A solvatochromism study was undertaken to determine the influence of the polarity solvent effect on compound 5e. Hence, solvents such as hexane, DCM, EtOAc, dioxane, CHCl3, and ACN in the increasing order of polarity were used for the study. The results revealed that a red shift in the emission maxima from 374 to 428 nm was observed as the polarity of the solvent was increased and found to have the highest emission wavelength at 428 nm in ACN (Table 4, Figure 6). Furthermore, compound 5e showed stokes shifts Δυ̅ = 11723 cm–1 (Table 5, entry 5).
Figure 5.
Normalized absorption and emission spectra of compound 5e.
Table 4. Absorption and Emission Maxima of Compound 5e in Various Polarity of Solvents.
| entry | solvent | absorptiona λmax,abs (nm) | emissionb λmax,emi (nm) |
|---|---|---|---|
| 1 | hexane | 283, 308 | 374 |
| 2 | DCM | 287, 310 | 395 |
| 3 | EtOAc | 287, 310 | 408 |
| 4 | dioxane | 284, 309 | 387 |
| 5 | CHCl3 | 286, 310 | 382 |
| 6 | ACN | 285, 308 | 428 |
Recorded at C = 10–4 M at 298 K.
Excited at the longest wavelength of the absorption maxima.
Figure 6.
Solvatochromism for compound 5e recorded at C = 10–4 M at 298 K: (a) normalized absorption spectra and (b) normalized emission spectra.
Table 5. Photophysical Properties of Compounds 5a–5e.
| entry | product | absorptiona λmax,abs (nm) | emission λmax,emi. (nm) | Stokes shift (cm–1)b |
|---|---|---|---|---|
| 1 | 5a | 257 | 385 | 12936 |
| 2 | 5b | 261 | 379 | 11928 |
| 3 | 5c | 259 | 371 | 11655 |
| 4 | 5d | 269 | 358 | 9241 |
| 5 | 5e | 285 | 428 | 11723 |
Recorded in CH3CN at 298 K.
Stokes shift = λmax,abs – λmax,emi [cm–1].
Similarly, photophysical characteristics such as absorption (λmax,abs), emission (λmax,emi), and Stokes shift (Δυ̅) of all the synthesized biaryl compounds 5a–5e were evaluated, and the results are summarized in Table 5. Normalized absorption and emission spectra of compounds 5a–5e are shown in Figure 7. Compounds 5a–5e exhibited absorption and emission maxima in 257–285 and 358–428 nm, respectively. All the synthesized biaryl compound Stokes shifts were calculated and showed large Stokes shifts; particularly, compound 5a has the highest Stokes shift value of 12936 cm–1, while compound 5d has the lowest Stocks shifts value of 9241 cm–1.
Figure 7.
(a) Normalized absorption spectra of compounds 5a–5e recorded in CH3CN at C = 10–4 M at 298 K; (b) normalized emission spectra of compounds 5a–5e recorded in CH3CN at C = 10–4 M at 298 K.
In summary, a number of highly functionalized 7-aza-N-methyl indole appended 9-(phenylethynyl)-fluorene derivatives 3a–3x have been synthesized. The scope of the reaction has been demonstrated by selecting a range of fluorene propargyl alcohols and substituting 7-aza indoles. A plausible reaction mechanism has been explained. Synthetic transformation of the products has been demonstrated by the Suzuki coupling reaction of 5a–5e and the Click reaction of 6. The photophysical properties of the Suzuki coupling reaction were evaluated, and luminescence was found in the blue region.
Experimental Section
General Remarks
All the reactions were carried out in oven-dried glassware. Progress of reactions was monitored by thin-layer chromatography (TLC), while purification of crude compounds was done by column chromatography using silica gel (mesh size 100–200). The NMR spectra were recorded on a Bruker-400 MHz NMR spectrometer (400 MHz for 1H NMR and 100 MHz for 13C NMR) with CDCl3or (CD3)2SO as the solvent and TMS as an internal reference. Integrals are by assignments; coupling constants were reported in hertz (Hz). All 13C spectra are proton-decoupled. Multiplicity is indicated as follows: s (singlet), d (doublet), t (triplet), q (quartet), m (multiplet), dd (doublet of doublet), br s (broad singlet). HRMS analyses were recorded using Q-T of a micro mass spectrometer (different mass analyses based on the availability of instruments). Yields refer to quantities obtained after chromatography.
Experimental Procedures
(a) General Procedures for the Preparation of Compounds 3a–3x
To a solution of propargylic alcohol derivatives of fluorenones 1a–1k (1 equiv) and substituted 7-aza indoles 2a–2f (1 equiv) in DCM (2 mL) was added BF3·OEt2 (1 equiv), and the reaction mixture was stirred at 45 °C for 10 min. After completion of the reaction (monitored by TLC), the reaction mixture was extracted with DCM, washed with saturated brine and distilled water, and dried over Na2SO4, and the solvent was evaporated under reduced pressure. The crude product was purified on a silica gel column to pure compound 3a–3x in excellent yield (eluent: n-hexane/EtOAc).
(b) General Procedures for the Suzuki Coupling of Compounds 5a–5e
A mixture of compound 3a (1 equiv), aryl boronic acids 4a–4d (1 equiv), Pd(dppf)Cl2·DCM (0.2 equiv), and K2CO3 (1.5 equiv) in 4 mL of dioxane-MeOH (3:1) was microwave irradiated (power mode) at 100 W for 10 min. After the reaction (TLC) was completed, the solvent was removed in vacuo, and the residue was extracted with EtOAc and washed with HCl (0.25 M, 20 mL) followed by saturated brine. The organic layer was dried over anhydrous Na2SO4 and purified through a silica gel column chromatography by gradient elution using EtOAc:hexane to afford compounds 5a–5e in very good yields.
(c) General Procedures for the Click Reaction of Compound 6
A mixture of compound 3i (1 equiv), NaN3 (1.2 equiv), benzyl bromide (1 equiv), triethylamine (1 equiv), and CuI (2.5 mol %) in 2 mL of DMF: water (1: 1) was stirred at room temperature for 30 min. Upon completion of the reaction, the catalyst was filtered, and the crude mixture was extracted with ethyl acetate. The combined organic layer was dried over anhydrous Na2SO4. The solvent was removed under vacuum; the crude product was purified using silica gel column chromatography to afford pure triazole derivative 6.
5-Bromo-1-methyl-3-(9-(phenylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3a)
Nature: yellow liquid; 210 mg, yield: 83%; Rf (15% EtOAc-hexane): 0.40; 1H NMR(CDCl3/TMS, 400 MHz,): δ 8.26–8.18 (m, 1H), 7.81 (d, J = 7.5 Hz, 2H), 7.54 (s, 2H), 7.48–7.37 (m, 5H), 7.33–7.19 (m, 6H), 3.80 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.8, 146.8, 143.5, 139.5, 131.9, 130.2, 128.9, 128.5, 128.4, 128.3, 128.2, 125.1, 123.2, 120.4, 119.3, 114.5, 111.4, 90.2, 81.9, 49.2, 31.4; HRMS-ESI: Calcd. for C29H20BrN2 [M + H]+m/z: 475.0810; Found 475.0805.
4-Bromo-1-methyl-3-(9-(phenylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3b)
Nature: white powder; 76 mg, yield: 64%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 7.80 (d, J = 7.6 Hz, 2H), 7.50 (d, J = 7.6 Hz, 2H), 7.46–7.37 (m, 5H), 7.30–7.23 (m, 5H), 6.87–6.81 (m, 2H), 3.81 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.9, 148.0, 139.5, 134.9, 131.9, 130.1, 128.5, 128.4, 128.3, 127.7, 125.2, 123.2, 120.3, 119.0, 116.4, 115.4, 90.1, 81.9, 49.3, 31.5; HRMS-ESI: Calcd. for C29H22BrN2 [M + 2]+m/z: 477.081; Found 477.0770.
1-Methyl-3-(9-(phenylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3c)
Nature: yellow liquid; 103 mg, yield: 73%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.18 (dd, J = 4.6, 1.0 Hz, 1H), 7.81 (d, J = 7.6 Hz, 2H), 7.54 (d, J = 7.6 Hz, 2H), 7.49 (s, 1H), 7.47–7.45 (m, 2H), 7.40 (dt, J = 7.5, 3.7 Hz, 2H), 7.30–7.25 (m, 5H), 7.04 (d, J = 7.9 Hz, 5H), 6.73 (dd, J = 8.0, 4.7 Hz, 1H), 3.86 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 149.2, 148.5, 142.9, 139.6, 132.2, 131.9, 128.4, 128.3, 128.2, 128.1, 127.6, 125.3, 123.3, 120.2, 117.9, 115.3, 114.7, 90.5, 81.7, 49.4, 31.3; HRMS-ESI: Calcd. for C29H21N2 [M + H]+m/z: 397.1705; Found 397.1696.
1-Allyl-3-(9-(phenylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3d)
Nature: brown liquid; 58 mg, yield: 39%; Rf (20% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.16 (dd, J = 4.7, 1.5 Hz, 1H), 7.82 (d, J = 7.6 Hz, 2H), 7.57 (s, 1H), 7.55–7.49 (m, 2H), 7.46–7.37 (m, 4H), 7.30–7.25 (m, 5H), 6.98–6.93 (m, 1H), 6.71 (dd, J = 8.0, 4.7 Hz, 1H), 6.13–6.01 (m, 1H), 5.22 (dd, J = 10.2, 1.3 Hz, 1H), 5.12 (dd, J = 17.0, 1.3 Hz, 1H), 4.93–4.87 (m, 2H); 13C NMR (CDCl3/TMS, 100 MHz): δ 149.2, 148.1, 142.9, 139.6, 133.9, 131.9, 128.9, 128.4, 128.3, 128.2, 128.1, 12.9, 127.7, 126.5, 125.3, 123.4, 120.2, 117.8, 117.4, 117.3, 115.8, 115.6, 115.1, 90.5, 81.7, 49.5, 46.7; MS-ESI: Calcd. for C13H22N2 [M + H]+m/z: 422.17; Found 422.15.
5-Bromo-1-methyl-3-(9-(p-tolylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3e)
Nature: yellow powder; 197 mg, yield: 79%; Rf (20% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.13 (d, J = 2.1 Hz, 1H), 7.75 (d, J = 7.6 Hz, 2H), 7.44 (d, J = 7.6 Hz, 2H), 7.39–7.31 (m, 3H), 7.29–7.25 (m, 2H), 7.22 (td, J = 7.5, 1.1 Hz, 2H), 7.12 (d, J = 2.1 Hz, 1H), 7.02 (d, J = 7.9 Hz, 2H), 3.74 (s, 3H), 2.25 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.9, 146.9, 143.5, 139.5, 138.4, 131.8, 130.2, 129.1, 128.9, 128.5, 128.4, 125.2, 120.4, 120.1, 119.3, 114.7, 111.4, 89.3, 82.1, 49.2, 31.5, 21.6; HRMS-ESI: Calcd. for C30H24BrN [M + 2]+m/z: 491.0966; Found 491.0946.
1-Benzyl-5-bromo-3-(9-(p-tolylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3f)
Nature: brown liquid; 108 mg, yield: 56%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.10 (d, J = 2.2 Hz, 1H), 7.69 (d, J = 7.6 Hz, 2H), 7.44 (s, 1H), 7.39 (d, J = 7.5 Hz, 2H), 7.29 (td, J = 7.5, 1.1 Hz, 2H), 7.21–7.13 (m, 7H), 7.10–7.05 (m, 2H), 7.02 (d, J = 2.1 Hz, 1H), 6.94 (d, J = 7.9 Hz, 2H), 5.30 (s, 2H), 2.18 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.8, 146.8, 143.7, 139.5, 138.3, 137.4, 131.7, 130.2, 129.0, 128.9, 128.5, 128.4128.0, 127.8, 127.4, 25.1, 120.4, 120.0, 119.2, 115.4, 111.6, 89.3, 82.1, 49.3, 48.2, 21.5; HRMS-ESI: Calcd. for C36H26BrN2 [M + H]+m/z: 565.1279; Found 565.1278.
5-Bromo-1-(prop-2-yn-1-yl)-3-(9-(p-tolylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3g)
Nature: yellow powder; 136 mg, yield: 78%; Rf (10% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.20 (d, J = 1.9 Hz, 1H), 7.83 (d, J = 7.6 Hz, 2H), 7.71 (s, 1H), 7.52 (d, J = 7.6 Hz, 2H), 7.43 (t, J = 7.5 Hz, 2H), 7.37–7.22 (m, 5H), 7.10 (dd, J = 4.9, 2.7 Hz, 3H), 5.02 (d, J = 2.5 Hz, 2H), 2.33 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.7, 146.2, 143.7, 139.6, 138.4, 131.8, 130.4, 129.1, 128.6, 128.5, 127.1, 125.2, 120.4, 120.1, 119.6, 115.9, 111.9, 89.2, 82.2, 73.7, 49.3, 33.9, 21.6; MS-ESI: Calcd. for C32H21BrN2 [M + H]+m/z: 512.08; Found 512.05.
1-Methyl-3-(9-(p-tolylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3h)
Nature: yellow powder; 107 mg, yield: 77%; Rf (20% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.18 (d, J = 4.4 Hz, 1H), 7.81 (d, J = 7.6 Hz, 2H), 7.53 (d, J = 7.3 Hz, 2H), 7.48 (s, 1H), 7.39 (td, J = 7.5, 0.9 Hz, 2H), 7.34 (d, J = 8.0 Hz, 2H), 7.29–7.22 (m, 2H), 7.06 (dd, J = 16.1, 8.1 Hz, 3H), 6.72 (ddd, J = 8.0, 4.7, 0.5 Hz, 1H), 3.85 (s, 3H), 2.32 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 149.3, 148.5, 142.8, 139.6, 138.3, 131.8, 129.1, 128.3, 128.2, 127.7, 125.3, 120.3, 120.2, 117.9, 115.3, 114.8, 89.7, 81.8, 49.4, 31.3, 21.6; HRMS-ESI: Calcd. for C30H23N2 [M + H]+m/z: 411.1861; Found 411.1862.
1-Allyl-3-(9-(p-tolylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3i)
Nature: brown liquid; 113 mg, yield: 76%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.08 (dd, J = 4.7, 1.4 Hz, 1H), 7.74 (d, J = 7.5 Hz, 2H), 7.49 (s, 1H), 7.44 (d, J = 7.6 Hz, 2H), 7.33 (td, J = 7.5, 1.0 Hz, 2H), 7.26 (d, J = 8.1 Hz, 2H), 7.23–7.16 (m, 2H), 7.01 (d, J = 7.9 Hz, 2H), 6.88 (dd, J = 7.9, 1.3 Hz, 1H), 6.63 (dd, J = 8.0, 4.7 Hz, 1H), 6.06–5.93 (m, 1H), 5.14 (dd, J = 10.2, 1.3 Hz, 1H), 5.04 (dd, J = 17.1, 1.3 Hz, 1H), 4.82 (d, J = 5.5 Hz, 2H), 2.25 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 149.3, 148.1, 142.9, 139.6, 138.3, 133.9, 131.8, 129.1, 128.4, 128.3, 128.1, 126.5, 125.3, 120.3, 120.2, 117.8, 117.4, 115.6, 115.2, 89.7, 81.8, 49.5, 46.7, 21.5; MS-ESI: Calcd. for C32H24N2 [M + H]+m/z: 436.19; Found 436.21.
5-Bromo-1-methyl-3-(9-(m-tolylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3j)
Nature: yellow powder; 125 mg, yield: 76%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.21 (d, J = 2.1 Hz, 1H), 7.81 (d, J = 7.6 Hz, 2H), 7.52 (d, J = 7.5 Hz, 2H), 7.45–7.38 (m, 3H), 7.32–7.22 (m, 5H), 7.16 (t, J = 7.6 Hz, 1H), 7.09 (d, J = 7.6 Hz, 1H), 3.80 (s, 3H), 2.29 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.8, 146.8, 143.5, 139.5, 138.0, 132.5, 130.2, 129.2, 128.9, 128.5, 128.4, 128.3, 125.1, 122.9, 120.4, 119.3, 114.6, 111.4, 89.8, 82.2, 49.2, 31.4, 21.3; HRMS-ESI: Calcd. for C30H24BrN2 [M + 2]+m/z: 491.0966; Found 491.0946.
5-Bromo-3-(9-((4-ethylphenyl)ethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3k)
Nature: yellow liquid; 79 mg, yield: 69%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.21 (d, J = 2.2 Hz, 1H), 7.80 (d, J = 7.6 Hz, 2H), 7.52 (d, J = 7.6 Hz, 2H), 7.44–7.34 (m, 5H), 7.28 (td, J = 7.5, 1.1 Hz, 2H), 7.21 (d, J = 2.6 Hz, 1H), 7.11 (d, J = 8.3 Hz, 2H), 3.79 (s, 3H), 2.60 (q, J = 7.6 Hz, 2H), 1.19 (t, J = 7.6 Hz, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.9, 146.8, 144.7, 143.5, 139.5, 131.9, 130.2, 128.9, 128.5, 128.4, 127.9, 125.2, 120.4, 119.3, 114.7, 111.4, 89.4, 82.2, 49.2, 31.4, 28.9, 15.5; HRMS-ESI: Calcd. for C31H24BrN2 [M + H]+m/z: 503.1123; Found 503.1114.
4-Bromo-3-(9-((4-ethylphenyl)ethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3l)
Nature: white powder; 68 mg, yield: 60%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 7.80 (d, J = 7.6 Hz, 2H), 7.50 (d, J = 7.6 Hz, 2H), 7.45 (s, 1H), 7.39 (ddd, J = 12.8, 9.6, 4.6 Hz, 4H), 7.30–7.24 (m, 2H), 7.11 (d, J = 8.2 Hz, 2H), 6.88–6.82 (m, 2H), 3.82 (s, 3H), 2.62 (q, J = 7.6 Hz, 2H), 1.61 (s, 1H), 1.20 (t, J = 7.6 Hz, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 149.0, 148.0, 144.7, 139.5, 134.9, 131.9, 130.2, 128.5, 128.4, 127.9, 127.7, 125.2, 120.4, 120.3, 119.0, 116.5, 115.6, 89.3, 82.1, 49.3, 31.6, 28.9, 15.5; HRMS-ESI: Calcd. for C31H24BrN2 [M + H]+m/z: 503.1123; Found 503.139.
3-(9-((4-Ethylphenyl)ethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3m)
Nature: white powder; 69 mg, yield: 72%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.18 (dd, J = 4.7, 1.4 Hz, 1H), 7.80 (d, J = 7.6 Hz, 2H), 7.53 (dd, J = 7.6, 0.4 Hz, 2H), 7.48 (s, 1H), 7.39 (ddd, J = 8.1, 5.6, 1.8 Hz, 4H), 7.27 (td, J = 7.5, 1.0 Hz, 2H), 7.11 (d, J = 8.0 Hz, 2H), 7.05 (d, J = 8.0 Hz, 1H), 6.72 (dd, J = 8.0, 4.7 Hz, 1H), 3.85 (s, 3H), 2.61 (q, J = 7.6 Hz, 2H), 1.19 (t, J = 7.6 Hz, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 149.3, 148.5, 144.6, 142.8, 139.6, 131.9, 128.3, 128.1, 127.9, 127.6, 125.3, 120.5, 120.2, 117.9, 115.3, 114.8, 89.7, 81.9, 49.4, 31.3, 29.9, 15.5; HRMS-ESI: Calcd. for C31H25N2 [M + H]+m/z: 425.2018; Found 425.2009.
5-Bromo-3-(9-((4-butylphenyl)ethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3n)
Nature: white powder; 78 mg, yield: 70%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.13 (d, J = 2.2 Hz, 1H), 7.74 (d, J = 7.6 Hz, 2H), 7.44 (d, J = 7.6 Hz, 2H), 7.38–7.31 (m, 3H), 7.28 (d, J = 8.2 Hz, 2H), 7.21 (td, J = 7.5, 1.1 Hz, 2H), 7.12 (d, J = 2.1 Hz, 1H), 7.02 (d, J = 8.2 Hz, 2H), 3.73 (s, 3H), 2.54–2.46 (m, 2H), 1.48 (ddd, J = 15.4, 11.0, 7.5 Hz, 2H), 1.30–1.16 (m, 3H), 0.82 (t, J = 7.3 Hz, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.9, 146.9, 143.5, 143.4, 139.5, 131.8, 130.2, 128.9, 128.5, 128.4, 125.2, 120.4, 120.3, 119.3, 114.7, 111.4, 89.4, 82.1, 49.2, 35.7, 33.5, 31.5, 22.4, 14.0; MS-ESI: Calcd. for C33H27BrN2 [M + H]+m/z: 530.13; Found 530.10.
5-Bromo-3-(9-((4-bromophenyl)ethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3o)
Nature: white powder; 145 mg, yield: 75%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.26 (d, J = 2.1 Hz, 1H), 7.86 (d, J = 7.6 Hz, 2H), 7.55 (d, J = 7.6 Hz, 2H), 7.47 (dd, J = 10.7, 7.9 Hz, 5H), 7.37–7.31 (m, 4H), 7.24 (d, J = 2.1 Hz, 1H), 3.86 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.5, 146.8, 143.6, 139.5, 133.4, 131.6, 130.1, 128.8, 128.7, 128.5, 125.1, 122.5, 122.1, 120.5, 119.3, 114.3, 111.4, 91.4, 80.9, 49.2, 31.5; HRMS-ESI: Calcd. for C29H19Br2N2 [M + H]+m/z: 552.9915; Found 552.9897.
1-Benzyl-5-bromo-3-(9-((4-bromophenyl)ethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3p)
Nature: yellow liquid; 124 mg, yield: 71%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.21 (d, J = 2.1 Hz, 1H), 7.79 (d, J = 7.5 Hz, 2H), 7.51–7.45 (m, 3H), 7.42–7.34 (m, 4H), 7.32–7.24 (m, 5H), 7.23–7.21 (m, 1H), 7.19 (dt, J = 11.3, 4.2 Hz, 3H), 7.10 (d, J = 2.1 Hz, 1H), 5.41 (s, 2H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.4, 146.8, 143.8, 139.5, 137.3, 133.3, 131.5, 130.2, 128.8, 128.6, 128.5, 127.9, 127.8, 127.5, 125.1, 122.5, 122.0, 120.5, 119.1, 114.9, 111.7, 91.4, 80.9, 49.3, 48.2; MS-ESI: Calcd. for C35H22Br2N2 [M + H]+m/z: 628.01; Found 628.03.
3-(9-((4-Bromophenyl)ethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3q)
Nature: yellow liquid; 108 mg, yield: 82%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.18 (dd, J = 4.7, 1.5 Hz, 1H), 7.82 (d, J = 7.6 Hz, 2H), 7.52 (d, J = 7.6 Hz, 2H), 7.45 (s, 1H), 7.43–7.38 (m, 4H), 7.32–7.25 (m, 4H), 7.03 (dd, J = 8.0, 1.5 Hz, 1H), 6.73 (dd, J = 8.0, 4.7 Hz, 1H), 3.86 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.9, 148.4, 142.9, 139.6, 133.4, 131.6, 128.5, 1284, 128.1, 127.5, 125.2, 122.4, 122.3, 120.3, 117.8, 115.4, 114.4, 91.8, 80.7, 49.4, 31.4; HRMS-ESI: Calcd. for C29H20BrN2 [M + H]+m/z: 475.0810; Found 475.0788.
3-(9-((4-Methoxyphenyl)ethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3r)
Nature: yellow liquid; 48 mg, yield: 70%; Rf (25% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.18 (dd, J = 4.7, 1.5 Hz, 1H), 7.84–7.78 (m, 2H), 7.53 (d, J = 7.5 Hz, 2H), 7.48 (s, 1H), 7.39 (ddd, J = 6.8, 5.0, 1.2 Hz, 4H), 7.31–7.22 (m, 2H), 7.07–7.00 (m, 1H), 6.84–6.77 (m, 2H), 6.72 (dd, J = 8.0, 4.7 Hz, 1H), 3.86 (s, 3H), 3.78 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 159.6, 149.4, 148.5, 142.9, 142.8, 139.6, 133.3, 129.9, 128.3, 128.2, 128.1, 127.6, 125.3, 120.2, 117.9, 115.6, 115.5, 115.3, 114.9, 113.9, 99.4, 88.9, 81.6, 55.4, 31.3; MS-ESI: Calcd. for C30H22N2O [M + H]+m/z: 426.17; Found 426.14.
1-Benzyl-5-bromo-3-(9-((4-methoxy-2-methylphenyl)ethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3s)
Nature: yellow powder; 61 mg, yield: 67%; Rf (20% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.34 (d, J = 2.1 Hz, 1H), 7.96 (d, J = 2.2 Hz, 1H), 7.72 (d, J = 7.5 Hz, 2H), 7.29 (td, J = 7.5, 1.1 Hz, 2H), 7.24 (d, J = 1.6 Hz, 1H), 7.23–7.20 (m, 3H), 7.17–7.10 (m, 4H), 6.96 (d, J = 7.5 Hz, 2H), 6.46–6.43 (m, 1H), 6.00 (d, J = 2.4 Hz, 1H), 5.98 (s, 1H), 5.44 (s, 2H), 3.51 (s, 3H), 1.97 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 158.8, 151.4, 146.2, 145.9, 144.2, 142.0, 138.6, 137.9, 137.4, 135.4, 132.4, 130.4, 128.9, 128.0, 127.9, 127.8, 127.7, 127.6, 123.9, 122.4, 120.3, 112.6, 112.2, 111.4, 107.0, 66.9, 55.4, 48.2, 19.8; MS-ESI: Calcd. for C37H27BrN2O [M + H]+m/z: 594.13; Found 594.10.
3-(2-Bromo-9-(phenylethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3t)
Nature: colorless liquid; 69 mg, yield: 73%; Rf (20% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.18 (dd, J = 4.7, 1.5 Hz, 1H), 7.82 (d, J = 7.6 Hz, 2H), 7.52 (d, J = 7.6 Hz, 2H), 7.45 (s, 1H), 7.43–7.38 (m, 4H), 7.32–7.25 (m, 4H), 7.03 (dd, J = 8.0, 1.5 Hz, 1H), 6.73 (dd, J = 8.0, 4.7 Hz, 1H), 3.86 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 149.2, 147.1, 142.6, 138.2, 138.1, 132.7, 132.0, 129.9, 129.2, 129.1, 129.0, 128.8, 128.3, 128.0, 124.6, 122.2, 122.1, 121.6, 120.4, 115.5, 99.4, 88.5, 83.7, 75.0, 31.5; HRMS-ESI: Calcd. for C29H20BrN2 [M + H]+m/z: 475.0810; Found 475.0805.
5-Bromo-3-(2-bromo-9-(phenylethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3u)
Nature: yellow liquid; 78 mg, yield: 72%; Rf (20% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.14 (d, J = 2.1 Hz, 1H), 7.74–7.70 (m, 1H), 7.60 (d, J = 8.1 Hz, 1H), 7.53 (d, J = 1.8 Hz, 1H), 7.46 (dd, J = 8.1, 1.8 Hz, 1H), 7.42 (d, J = 3.5 Hz, 1H), 7.41–7.37 (m, 3H), 7.35 (dd, J = 7.5, 1.1 Hz, 1H), 7.26–7.20 (m, 4H), 7.00 (d, J = 2.1 Hz, 1H), 3.76 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 150.7, 148.6, 146.8, 143.7, 138.5, 138.4, 131.9, 131.7, 129.5, 129.2, 128.9, 128.8, 128.5, 128.4, 125.2, 122.9, 122.0, 121.8, 120.5, 119.0, 113.6, 111.5, 89.2, 82.5, 49.2, 31.5; HRMS-ESI: Calcd. for C29H19Br2N2 [M + H]+m/z: 552.9915; Found 552.9901.
1-Benzyl-5-bromo-3-(2-bromo-9-(phenylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (3v)
Nature: yellow liquid; 73 mg, yield: 42%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.12 (d, J = 2.1 Hz, 1H), 7.65 (d, J = 7.6 Hz, 1H), 7.54–7.49 (m, 3H), 7.41–7.33 (m, 2H), 7.31–7.25 (m, 3H), 7.23–7.12 (m, 7H), 7.09 (dd, J = 9.3, 2.6 Hz, 2H), 6.91 (d, J = 2.1 Hz, 1H), 5.32 (s, 2H); 13C NMR (CDCl3/TMS, 100 MHz): δ 150.6, 148.4, 146.8, 143.9, 138.5, 138.4, 137.2, 131.9, 131.7, 129.9, 128.9, 128.8, 128.4, 120.3, 128.2, 127.9, 127.5, 125.2, 122.8, 122.0, 121.7, 120.5, 118.9, 114.3, 111.8, 89.2, 82.5, 49.3, 48.2; HRMS-ESI: Calcd. for C29H20BrN2 [M + H]+m/z: 475.0810; Found 475.0805.
5-Bromo-3-(2-bromo-9-(p-tolylethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3w)
Nature: yellow powder; 79 mg, yield: 65%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.14 (d, J = 2.1 Hz, 1H), 7.75–7.70 (m, 1H), 7.62–7.58 (m, 1H), 7.53 (d, J = 1.5 Hz, 1H), 7.46 (dd, J = 8.1, 1.8 Hz, 1H), 7.43–7.34 (m, 3H), 7.31–7.21 (m, 3H), 7.06–6.98 (m, 3H), 3.77 (s, 3H), 2.26 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 150.9, 148.7, 146.9, 143.7, 138.7, 138.5, 138.4, 131.8, 131.7, 129.9, 129.2, 129.1, 128.9, 128.7, 128.5, 125.2, 122.0, 121.8, 120.5, 119.8, 119.0, 113.8, 111.5, 88.4, 82.6, 49.3, 31.5, 21.6; MS-ESI: Calcd. for C30H20Br2N2 [M + H]+m/z: 565.99; Found 565.96.
5-Bromo-3-(2,7-dibromo-9-(phenylethynyl)-9H-fluoren-9-yl)-1-methyl-1H-pyrrolo[2,3-b]pyridine (3x)
Nature: yellow powder; 63 mg, yield: 44%; Rf (15% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.24 (d, J = 2.1 Hz, 1H), 7.67 (d, J = 8.1 Hz, 2H), 7.57 (dd, J = 3.5, 1.5 Hz, 3H), 7.55 (d, J = 2.0 Hz, 2H), 7.50–7.46 (m, 2H), 7.37–7.30 (m, 3H), 7.01 (d, J = 2.1 Hz, 1H), 3.87 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 150.5, 146.9, 143.9, 137.4, 132.1, 132.0, 129.6, 129.4, 128.7, 128.5, 122.6, 122.5, 121.8, 118.8, 112.7, 111.7, 88.3, 83.0, 49.2, 31.6; MS-ESI: Calcd. for C29H17Br3N2 [M + H]+m/z: 629.89; Found 629.91.
1-Methyl-5-phenyl-3-(9-(phenylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (5a)
Nature: colorless liquid; 36 mg, yield: 60%; Rf (25% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.47 (s, 1H), 7.85 (d, J = 7.6 Hz, 2H), 7.62 (d, J = 7.6 Hz, 2H), 7.53–7.43 (m, 6H), 7.41–7.35 (m, 3H), 7.33 (dd, J = 3.9, 2.3 Hz, 7H), 3.92 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 149.1, 148.1, 142.3, 139.6, 132.0, 129.0, 128.9, 128.8, 128.4, 128.3, 128.2, 127.4, 127.2, 127.0, 126.8, 126.6, 125.5, 125.3, 123.4, 120.3, 117.9, 115.2, 90.6, 81.9, 60.5, 49.4, 31.4; MS-ESI: Calcd. for C35H24N2 [M + H]+m/z: 472.19; Found 472.15.
1-Methyl-5-phenyl-3-(9-(p-tolylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (5b)
Nature: white powder; 16 mg, yield: 40%; Rf (30% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.36 (d, J = 2.1 Hz, 1H), 7.74 (d, J = 7.6 Hz, 2H), 7.50 (d, J = 7.5 Hz, 2H), 7.40 (s, 1H), 7.34 (td, J = 7.5, 1.1 Hz, 2H), 7.28 (t, J = 7.4 Hz, 4H), 7.24–7.18 (m, 6H), 7.02 (d, J = 7.9 Hz, 2H), 3.80 (s, 3H), 2.26 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 149.3, 148.0, 142.2, 139.6, 138.3, 131.8, 129.1, 128.9, 128.8, 128.4, 128.3, 128.2, 127.2, 126.8, 126.6, 125.3, 120.3, 120.2, 117.9, 115.3, 89.7, 82.0, 49.5, 31.5, 21.6; HRMS-ESI: Calcd. for C36H27N2 [M + H]+m/z: 487.2174; Found 487.2154.
5-(4-Methoxyphenyl)-1-methyl-3-(9-(m-tolylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (5c)
Nature: yellow liquid; 56 mg, yield: 67%; Rf (20% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.47 (s, 1H), 7.87 (d, J = 7.5 Hz, 2H), 7.65 (d, J = 7.6 Hz, 2H), 7.48 (dd, J = 16.4, 9.0 Hz, 3H), 7.36 (dd, J = 9.8, 5.1 Hz, 5H), 7.31–7.26 (m, 2H), 7.22 (dd, J = 13.1, 5.5 Hz, 1H), 7.15 (d, J = 7.6 Hz, 1H), 6.96 (d, J = 8.6 Hz, 2H), 3.92 (s, 3H), 3.86 (s, 3H), 2.34 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 158.9, 149.2, 147.8, 142.9, 142.0, 139.6, 138.0, 132.5, 132.1, 129.1, 128.9, 128.8, 128.5, 128.3, 128.2, 128.1, 126.2, 125.3, 123.1, 120.3, 117.9, 115.6, 115.0, 114.4, 99.4, 90.2, 82.0, 55.4, 49.4, 31.4, 21.2; MS-ESI: Calcd. for C37H28N2O [M + H]+m/z: 516.22; Found 516.25.
1-Methyl-3-(9-((4′-methyl-[1,1′-biphenyl]-4-yl)ethynyl)-9H-fluoren-9-yl)-5-(p-tolyl)-1H-pyrrolo[2,3-b]pyridine (5d)
Nature: yellow powder; 34 mg, yield: 85%; Rf (20% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.35 (d, J = 2.1 Hz, 1H), 7.73 (d, J = 7.6 Hz, 2H), 7.51 (d, J = 7.6 Hz, 2H), 7.43 (d, J = 4.8 Hz, 4H), 7.39 (d, J = 8.9 Hz, 3H), 7.33 (td, J = 7.5, 1.0 Hz, 2H), 7.22 (td, J = 7.5, 1.0 Hz, 2H), 7.18–7.13 (m, 3H), 7.12–7.06 (m, 4H), 3.80 (s, 3H), 2.30 (s, 3H), 2.27 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 149.2, 147.8, 142.1, 140.9, 139.6, 137.6, 136.6, 132.3, 129.7, 129.6, 128.8, 128.4, 128.2, 127.1, 126.9, 126.8, 126.5, 125.3, 121.9, 120.3, 118.0, 115.1, 91.1, 81.8, 49.5, 31.5, 21.2, 21.1; HRMS-ESI: Calcd. for C43H33N2 [M + H]+m/z: 577.2644; Found 577.2629.
4-(1-Benzyl-3-(2-(4-cyanophenyl)-9-(phenylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridin-5-yl)benzonitrile (5e)
Nature: yellow liquid; 37 mg, yield: 58%; Rf (30% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.34 (d, J = 2.1 Hz, 1H), 7.83 (dd, J = 16.2, 7.8 Hz, 2H), 7.68–7.62 (m, 2H), 7.59 (d, J = 8.8 Hz, 3H), 7.54 (dd, J = 8.5, 3.2 Hz, 4H), 7.48 (d, J = 7.5 Hz, 1H), 7.41 (dd, J = 10.8, 4.2 Hz, 1H), 7.35–7.31 (m, 2H), 7.27 (dd, J = 11.2, 4.1 Hz, 4H), 7.24–7.18 (m, 6H), 6.93 (d, J = 1.7 Hz, 1H), 5.46 (s, 2H); 13C NMR (CDCl3/TMS, 100 MHz): δ 150.0, 149.4, 148.5, 145.3, 144.0, 142.4, 140.2, 139.3, 138.9, 137.5, 132.7, 132.6, 131.9, 129.0, 128.9, 128.8, 128.5, 128.4, 128.2, 127.9, 127.8, 127.6, 127.5, 127.3, 126.5, 125.5, 124.0, 121.0, 120.6, 119.0, 117.5, 115.8, 111.0, 110.5, 82.4, 49.5, 48.2; MS-ESI: Calcd. for C49H30N4 [M + H]+m/z: 674.24; Found 674.22.
1-((1-Benzyl-1H-1,2,3-triazol-5-yl)methyl)-5-bromo-3-(9-(p-tolylethynyl)-9H-fluoren-9-yl)-1H-pyrrolo[2,3-b]pyridine (6)
Nature: yellow liquid; 53 mg, yield: 60%; Rf (30% EtOAc-hexane): 0.40; 1H NMR (CDCl3/TMS, 400 MHz,): δ 8.16 (t, J = 1.9 Hz, 1H), 7.79 (d, J = 7.6 Hz, 2H), 7.66 (d, J = 3.2 Hz, 1H), 7.49–7.43 (m, 2H), 7.42–7.36 (m, 3H), 7.33–7.29 (m, 5H), 7.24 (d, J = 6.6 Hz, 2H), 7.20 (dd, J = 6.6, 2.9 Hz, 2H), 7.13 (t, J = 2.4 Hz, 1H), 7.07 (d, J = 8.0 Hz, 2H), 5.47 (s, 2H), 5.42 (s, 2H), 2.31 (s, 3H); 13C NMR (CDCl3/TMS, 100 MHz): δ 148.7, 146.2, 144.3, 143.4, 139.4, 138.3, 134.4, 131.8, 130.3, 129.2, 129.0, 128.8, 128.5, 128.4, 128.1, 128.0, 125.1, 122.8, 120.3, 119.9, 119.5, 115.4, 111.7, 89.0, 82.2, 54.3, 49.2, 39.9, 25.5; MS-ESI: Calcd. for C39H28BrN5 [M + H]+m/z: 645.15; Found 645.18.
Acknowledgments
P.S. thanks the Director, CSIR-CLRI, for providing infrastructure facilities. The authors thank VIT-Vellore for single-crystal XRD analysis and CSIR-IICB, Kolkata, for HRMS data. This research work was carried out by S.S.S. as a part of a Ph. D. degree registered at the University of Madras.
Supporting Information Available
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.3c01255.
Copies of FTIR, 1H NMR, 13C NMR, and HRMS data for all of the new compounds and basic crystallographic data of compound 3b (PDF)
Author Present Address
§ Department of Polymer Science, University of Madras, Guindy Campus, Chennai 600025, India (S.S.S.)
The authors declare no competing financial interest.
Supplementary Material
References
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