Next Article in Journal
A Resolution-Free Parallel Algorithm for Image Edge Detection within the Framework of Enzymatic Numerical P Systems
Next Article in Special Issue
New Approach for the One-Pot Synthesis of 1,3,5-Triazine Derivatives: Application of Cu(I) Supported on a Weakly Acidic Cation-Exchanger Resin in a Comparative Study
Previous Article in Journal
Possible Role of the Ca2+/Mn2+ P-Type ATPase Pmr1p on Artemisinin Toxicity through an Induction of Intracellular Oxidative Stress
Previous Article in Special Issue
Highly Efficient Synthesis of Substituted 3,4-Dihydropyrimidin-2-(1H)-ones (DHPMs) Catalyzed by Hf(OTf)4: Mechanistic Insights into Reaction Pathways under Metal Lewis Acid Catalysis and Solvent-Free Conditions
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Molecules
Volume 24
Issue 7
10.3390/molecules24071234
molecules-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Communication

An Efficient, One-Pot Transamidation of 8-Aminoquinoline Amides Activated by Tertiary-Butyloxycarbonyl

by
Wengang Wu
1,
Jun Yi
2,*,
Huipeng Xu
2,
Shuangjun Li
2 and
Rongxin Yuan
2,*
1
College of Chemistry, Chemical Engineering and Materials Science of Soochow University, 199 Ren’ai Road, Suzhou, Jiangsu 215123, China
2
Jiangsu Laboratory of Advanced Functional Material, School of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu 215500, China
*
Authors to whom correspondence should be addressed.
Molecules 2019, 24(7), 1234; https://doi.org/10.3390/molecules24071234
Submission received: 5 March 2019 / Revised: 22 March 2019 / Accepted: 22 March 2019 / Published: 29 March 2019
(This article belongs to the Special Issue Advances in One-Pot Reaction)
Browse Figures
Review Reports Versions Notes

Abstract

:
The efficient, one-pot access to the transamidation of 8-aminoquinoline (8-AQ), notorious for its harsh removal conditions, has been widely employed as an auxiliary in C–H functionalization reactions due to its strong directing ability. In this study, the facile and mild Boc protection of the corresponding 8-AQ amide was critical to activate the amide C(acyl)–N bond by twisting its geometry to lower the amidic resonance energy. Both aryl and alkyl amines proceeded transamidation in one-pot, user-friendly conditions with excellent yields.

1. Introduction

C–H functionalization has emerged as a powerful strategy for building-up new molecules [1,2,3,4]. In the past decades, the growing interest in C–H functionalization has led to increased attention to this paradigm for organic synthesis, which has inspired exceptional advances in this field [5,6,7,8]. The maneuver of directing groups (DGs) in C–H functionalization has been proved to be pivotal to facilitate the desired transformation. Common DGs include ketones [9,10,11], esters [12,13,14], carboxylic acid [15,16,17], amides [18,19,20,21,22], etc. Among them, amides are one of the most frequently used motifs (Scheme 1(A)). Taking advantage of its strong coordination with transition metals, a myriad of contributions have been made, especially with bidentate amide DGs. In 2005, Daugulis [23] introduced 8-aminoquinoline (8-AQ) A2 to C–H functionalization, which has been widely used in Pd- [24,25,26,27], Rh- [28,29,30], Ru- [31], Ni- [32,33,34,35,36,37,38], Cu- [39,40,41], Co- [42,43,44], and Fe-catalyzed [45,46,47,48] C–H activation to enable various reactions.
As a result of electron delocalization (nN to πC═O*, ∆Hrot of ca. 15–20 kcal/mol in planar amides) [49], the difficulties in uninstalling amide DGs greatly constrain its application (Scheme 1B). Conventional deprotection required stoichiometric amounts of a strong base or acid (Scheme 1(B,B2)), which diminished the functional tolerance [37]. A milder, two-step strategy was therefore widely used, where 8-AQ amides were firstly transformed to tertiary amides by using di-tert-butyl decarbonate (Boc2O), which was subsequently hydrolyzed by lithium hydroxide and hydrogen peroxide (B2) [50]. Similarly, transesterification strategies by boron trifluoride-diethyl etherate (BF3·Et2O) were also limited due to the harsh Lewis acid BF3 (B3) [37]. Recently, Morimoto and Ohshima reported nickel-catalyzed alcoholysis of unactivated 8-aminoquinoline amides in neutral conditions with excellent functional compatibilities (B3); however, it is mostly limited to alkyl amides [51]. Inspired by the para-methoxyphenyl (PMP) protecting group for amines, Chen installed a methoxy group at the 5 position of 8-AQ for facile removal with ceric ammonium nitrate (CAN) under mild conditions (B4) [52]. Unfortunately, the modified auxiliary is expensive due to its multistep synthesis. Reduction with stoichiometric zirconocene hydrochloride (also known as Schwartz’s reagent) gives the corresponding aldehyde, yet this organometallic reagent is not user friendly [53]. Compared with the booming C–H functionalization reactions, the removal of auxiliary groups is still lagging behind. Meanwhile, Garg [54,55,56,57,58,59,60,61,62,63,64] and Szostak [65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83] proved that by increasing the sterics of the substitution group, the formation of twisted amides activates the amidyl C(acyl)–N bond to favor the insertion of low-valent metals, furnishing the acyl−metal intermediate for further transformations. Inspired by these advances in amidyl C(acyl)–N activation, we envisioned that 8-AQ removal could be achieved in this manner after C–H functionalized reactions (Figure 1).

2. Results

In order to test our proposal, first, the proper activating group of 8-AQ was chosen. We decided to choose Boc as the activating group for three reasons: (1) The installation of Boc was very moderate, which enhanced the functional group tolerance, with a nearly quantitative yield [84,85,86,87]. (2) 8-aminoquinoline can be easily recycled through deprotection of the tert-butyl quinolin-8-ylcarbamate byproduct. (3) Above all, Boc is one of the most thriving activation groups in amidyl C(acyl)–N transformation reactions.
Our study was initiated using 3-methyl-N-(quinolin-8-yl)benzamide (1a) with aniline (2a) as model substrates for transamidation in the presence of different bases (Table 1). We started screening with well-developed phosphine ligands. Unfortunately, neither PPh3 nor PCy3 gave a product. The more σ-donating N-heterocyclic carbenes (NHCs) have revealed high efficiency in inert bond activation, such as C–O [88], C–F [89], as well as amide transformation reactions [63,65,70]. As expected, when using NHC ligands, the desired product was observed. With these promising results, several NHC ligands were examined for transamidation reactions (entries 3–9). Although the combination of Ni(COD)2 and SIPr (entry 9) showed a higher yield than (IPr)Pd(cinnamyl)Cl (entry 6), due to the significant difference of stability under air, we decided to use (IPr)Pd(cinnamyl)Cl as the catalyst, which was more user friendly [77]. A higher temperature was critical to improve the yield (entry 10). Neither the strong base sodium tert-butoxide (entry 12) nor the organic base 1,8-diazabicyclo[5.4. 0]undec-7-ene (DBU) (entry 13) enhanced the yield. Switching the reaction solvent from THF to MeCN, dioxane or DMF resulted in lower yields (entries 14–16). The control experiment showed that the Pd catalyst was indispensable (entry 17). Finally, we attempted a one-pot transamidation (entry 18) and found that there was no detriment to the yield. The separation of 1a and 4-dimethylaminopyridine (DMAP) was not needed, which enhanced the step efficiency and made the reaction greener.
With the optimized condition in hand, the substrate comparability of the reaction was examined (Figure 2). First, we tested the amine scope. Methyl substitution on both para (3b) and ortho (3c) positions gave good yields, although the ortho position was more hindered. The electronic effect of the substitution groups did not have a great impact on the yield. Strong electron-donating (3f) as well as electron-withdrawing (3g) groups were all tolerated. Next, we tested the carboxylic acid part of the amide. The reaction still was not sensitive to the hindrance, as even the bulky ortho-phenoxy group gave an excellent yield (3k). Heterocycles such as quinoline (3m, 3n) did not corrupt the efficiency of the reaction, while it was noteworthy that even the challenging di-ortho-substituted aniline was tolerated (3m). More strikingly, aliphatic carboxylic acids, such as ibuprofen-derived species (3o), were also workable in this condition.
Next, we tried to expand the scope to aliphatic amines (Figure 3). The reaction took place without Pd catalysts, which was consistent with Szostak’s report [66,76]. For the primary amines, the reaction proceeded well even at room temperature (3p, 3q, 3r). For the secondary amines, although a higher temperature was required, the yield was still excellent (3s, 3t).
Finally, we scaled up the reaction to the gram scale (Scheme 2A) and found that the yield was consistent with the small-scale reactions. We also isolated the tert-butyl quinolin-8-ylcarbamate in 82% yield, from which the Boc deprotection can be removed quantitatively to recover the 8-AQ (Scheme 2B).
For the mechanism, we postulated that the amide bond was activated by Boc via a steric-induced geometry twist, which facilitated the oxidative addition of a Pd–NHC catalyst to generate an acylpalladium intermediate. The more nucleophilic amine then substituted the 8-AQ carbamate via ligand exchanges, which further underwent reductive elimination to form the product while regenerating the Pd(0) species.

3. Discussion

To summarize, we reported the Boc-activated transamidation of 8-AQ, which is a widely utilized auxiliary in C–H functionalization. Boc protection of the corresponding 8-AQ amide was critical to activate the amide C(acyl)–N bond by twisting its geometry and lowering the amidic resonance energy. Both aryl and alkyl amines proceeded transamidation in excellent yields. The facile and mild Boc activation of the amide C(acyl)–N bond as well as the user-friendly one-pot reaction procedure highlight its utilization in the future. This method provides alternative means to remove 8-AQ that is complementary to existing protocols. Future efforts will be directed toward expanding the types of new transformations as well as the different types of directing groups.

4. Experimental Section

4.1. Representative General Procedure for One-pot Transamidation of 8-Aminoquinoline Amides

8-aminoquinoline amide (0.2 mmol, 60.5 mg), di-tert-butyl-dicarbonate (52.4 mg, 1.2 equiv), N,N-dimethylpyridin-4-amine (26.9 mg, 1.1 equiv), and acetonitrile (2 mL, 0.1 M) were added to an oven-dried Schlenk pressure vessel equipped with a stir bar. The resulting reaction mixture was stirred at room temperature for 15 h. The solvent was removed under high vacuum after the indicated time. The same reaction vial was charged with aniline (28 mg, 0.3 mmol), potassium carbonate (55 mg, 2.0 equiv), and (IPr)Pd(cinnamyl)Cl (3.9 mg, 3 mol%) (not needed for alkyl amine), placed under a positive pressure of argon, and subjected to three evacuation/backfilling cycles under high vacuum. THF (2 mL, 0.1 M) was added with vigorous stirring at room temperature, and the reaction took place at the indicated temperate (aniline at 110 °C, primary amine at room temperature, and secondary amine at 80 °C) and was stirred for 24 h. The reaction mixture was cooled down to room temperature and diluted with ethyl acetate (10 mL) after the indicated time. The reaction mixture was filtered and concentrated. Purification by chromatography on silica gel (EtOAc/hexanes) afforded the product (yield: 88% (37.2 mg), white solid). Characterization data matched those described above.

4.2. Characterization Data for Products 3a–3u (Figure 2 and Figure 3)

3-Methyl-N-phenylbenzamide (3a): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 7.90 (s, 1H), 7.70–7.59 (m, 4H), 7.40–7.30 (m, 4H), 7.14 (t, J = 7.4 Hz, 1H), 2.41 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 166.0, 138.7, 138.0, 135.0, 132.5, 129.0, 128.6, 127.8, 124.5, 123.9, 120.2, 21.4.
3-Methyl-N-(p-tolyl)benzamide (3b): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 7.77 (s, 1H), 7.68 (s, 1H), 7.63 (dt, J = 5.7, 2.2 Hz, 1H), 7.58–7.50 (m, 2H), 7.39–7.31 (dd, J = 5.0, 1.9 Hz, 2H), 7.17 (d, J = 8.1 Hz, 2H), 2.42 (s, 3H), 2.34 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 165.8, 138.6, 135.4, 135.1, 134.1, 132.4, 129.5, 128.6, 127.7, 123.9, 120.2, 21.4, 20.9.
3-Methyl-N-(o-tolyl)benzamide (3c): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 7.93 (d, J = 8.0 Hz, 1H), 7.76–7.59 (m, 3H), 7.37 (d, J = 5.5 Hz, 2H), 7.29–7.19 (m, 2H), 7.11 (t, J = 7.5 Hz, 1H), 2.44 (s, 3H), 2.33 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 165.8, 138.8, 135.8, 135.0, 132.6, 130.5, 129.2, 128.6, 127.9, 126.9, 125.3, 123.9, 123.1, 21.4, 17.8.
N-(4-Methoxyphenyl)-3-methylbenzamide (3d): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 7.69 (d, J = 8.8 Hz, 2H), 7.63 (d, J = 6.3 Hz, 1H), 7.58–7.50 (m, 2H), 7.40–7.31 (m, 2H), 6.95–6.86 (m, 2H), 3.82 (s, 3H), 2.43 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 166.0, 156.5, 138.5, 134.9, 132.3, 131.1, 128.4, 127.8, 124.0, 122.2, 114.1, 55.4, 21.3.
N-(2-Methoxyphenyl)-3-methylbenzamide (3e): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 8.53 (d, J = 6.6 Hz, 2H), 7.75–7.69 (m, 1H), 7.66 (d, J = 6.8 Hz, 1H), 7.37 (d, J = 7.3 Hz, 2H), 7.12–6.96 (m, 2H), 6.92 (d, J = 7.9 Hz, 1H), 3.93 (s, 3H), 2.44 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 165.5, 148.1, 138.6, 135.3, 132.4, 128.6, 127.8, 127.8, 123.9, 123.8, 121.2, 119.8, 109.9, 55.8, 21.4.
N-(2,5-Dimethoxyphenyl)-3-methylbenzamide (3f): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 8.56 (s, 1H), 8.29 (d, J = 3.0 Hz, 1H), 7.78–7.62 (m, 2H), 7.37 (d, J = 7.0 Hz, 2H), 6.83 (d, J = 8.9 Hz, 1H), 6.61 (dd, J = 8.9, 3.0 Hz, 1H), 3.88 (s, 3H), 3.82 (s, 3H), 2.44 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 165.4, 153.9, 142.3, 138.7, 135.2, 132.5, 128.6, 128.5, 127.8, 123.9, 110.7, 108.8, 105.9, 56.3, 55.8, 21.4.
3-Methyl-N-(3-nitrophenyl)benzamide (3g): Pale yellow solid. 1H-NMR (400 MHz, Chloroform-d) δ 8.49 (t, J = 2.1 Hz, 1H), 8.22 (s, 1H), 8.11 (d, J = 8.2 Hz, 1H), 7.98 (d, J = 8.2 Hz, 1H), 7.74–7.62 (m, 2H), 7.52 (t, J = 8.2 Hz, 1H), 7.37 (d, J = 5.3 Hz, 2H), 2.42 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 166.2, 148.6, 139.1, 138.9, 133.9, 133.2, 129.9, 128.8, 127.8, 125.9, 124.1, 119.0, 114.9, 21.3.
3-Methyl-N-(naphthalen-1-yl)benzamide (3h): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 8.20 (s, 1H), 8.03 (d, J = 7.5 Hz, 1H), 7.90 (dt, J = 6.5, 2.9 Hz, 2H), 7.84–7.70 (m, 3H), 7.52 (td, J = 8.0, 7.3, 4.4 Hz, 3H), 7.41 (d, J = 6.0 Hz, 2H), 2.46 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 166.5, 138.6, 134.7, 134.1, 132.6, 132.4, 128.7, 128.6, 128.0, 127.6, 126.2, 126.0, 125.9, 125.7, 124.1, 121.4, 120.9, 21.3.
2-Methyl-N-phenylbenzamide (3i): Pale yellow oil. 1H-NMR (400 MHz, Chloroform-d) δ 7.65 (d, J = 7.9 Hz, 2H), 7.57 (s, 1H), 7.50 (d, J = 7.6 Hz, 1H), 7.39 (t, J = 8.0 Hz, 3H), 7.29 (t, J = 5.3 Hz, 2H), 7.18 (t, J = 7.5 Hz, 1H), 2.53 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 168.2, 138.0, 136.4, 131.2, 130.2, 129.1, 126.6, 125.9, 124.5, 119.9, 19.8.
N-(4-Isopropoxyphenyl)-2-methylbenzamide (3j): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 7.84–7.61 (m, 3H), 7.54 (d, J = 8.4 Hz, 2H), 7.44–7.32 (m, 2H), 6.92 (d, J = 8.4 Hz, 2H), 4.63–4.47 (m, 1H), 2.45 (s, 3H), 1.36 (d, J = 6.0 Hz, 6H). 13C-NMR (101 MHz, CDCl3) δ 166.2, 154.7, 138.4, 134.9, 132.3, 131.1, 128.4, 127.9, 124.1, 122.3, 116.3, 70.2, 22.0, 21.3.
N-(3-Nitrophenyl)-2-phenoxybenzamide (3k): Yellow solid. 1H-NMR (400 MHz, Chloroform-d) δ 9.90 (s, 1H), 8.50 (d, J = 2.8 Hz, 1H), 8.35 (d, J = 7.9 Hz, 1H), 7.98 (dd, J = 14.1, 8.4 Hz, 2H), 7.47 (td, J = 10.7, 9.1, 5.7 Hz, 4H), 7.29 (d, J = 7.5 Hz, 2H), 7.16 (d, J = 8.0 Hz, 2H), 6.90 (d, J = 8.3 Hz, 1H). 13C-NMR (101 MHz, CDCl3) δ 163.1, 155.6, 154.9, 148.6, 139.2, 133.7, 132.6, 130.5, 129.7, 126.0, 125.4, 124.0, 123.0, 119.8, 118.9, 118.2, 115.1.
N-(2-Fluorophenyl)-4-methylbenzamide (3l): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 8.40 (d, J = 15.6 Hz, 1H), 8.24–8.12 (m, 1H), 7.60–7.46 (m, 3H), 7.31 (t, J = 7.6 Hz, 1H), 7.23–7.12 (m, 3H), 2.35 (s, 3H). 13C-NMR (101 MHz, Chloroform-d) δ 161.2, 160.4 (d, J = 246.2 Hz), 135.1, 134.4, 133.6 (d, J = 9.4 Hz), 132.3 (d, J = 2.0 Hz), 129.5, 125.0 (d, J = 3.3 Hz), 121.4 (d, J = 11.1 Hz), 120.5, 116.1 (d, J = 25.1 Hz).
N-Mesitylquinoline-2-carboxamide (3m): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 9.67 (s, 1H), 8.41 (q, J = 8.6 Hz, 2H), 8.20 (d, J = 8.5 Hz, 1H), 7.95 (d, J = 8.2 Hz, 1H), 7.83 (t, J = 7.8 Hz, 1H), 7.68 (t, J = 7.6 Hz, 1H), 6.99 (s, 2H), 2.34 (s, 3H), 2.32 (s, 6H). 13C-NMR (101 MHz, CDCl3) δ 162.7, 149.7, 146.5, 137.6, 136.8, 135.2, 131.2, 130.2, 129.8, 129.4, 128.9, 128.0, 127.8, 119.0, 21.0, 18.6.
N-Phenylquinoline-3-carboxamide (3n): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 10.27 (s, 1H), 8.41 (q, J = 8.5 Hz, 2H), 8.22 (d, J = 8.5 Hz, 1H), 8.00–7.78 (m, 4H), 7.68 (t, J = 7.6 Hz, 1H), 7.45 (t, J = 7.8 Hz, 2H), 7.21 (t, J = 7.4 Hz, 1H). 13C-NMR (101 MHz, CDCl3) δ 162.1, 149.6, 146.3, 137.9, 137.8, 130.3, 129.7, 129.4, 129.1, 128.2, 127.8, 124.3, 119.7, 118.7.
2-(4-Isobutylphenyl)-N-(4-methoxyphenyl)propenamide (3o): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 7.31 (d, J = 8.6 Hz, 2H), 7.26 (d, J = 7.2 Hz, 2H), 7.15 (d, J = 7.7 Hz, 2H), 6.97 (s, 1H), 6.80 (d, J = 8.6 Hz, 2H), 3.76 (s, 3H), 3.67 (q, J = 7.2 Hz, 1H), 2.47 (d, J = 7.1 Hz, 2H), 1.95–1.79 (m, 1H), 1.58 (d, J = 7.2 Hz, 3H), 0.91 (d, J = 6.6 Hz, 6H). 13C-NMR (101 MHz, CDCl3) δ 172.5, 156.3, 140.9, 138.2, 131.1, 129.7, 127.4, 121.6, 114.0, 55.4, 47.4, 45.0, 30.1, 22.3, 18.5.
N-(4-Methoxyphenyl)-2-methyl-2-phenylpropanamide (3p): White solid. 1H-NMR (400 MHz, DMSO-d6) δ 9.00 (s, 1H), 7.47 (d, J = 8.5 Hz, 2H), 7.42–7.30 (m, 4H), 7.24 (dt, J = 6.4, 3.1 Hz, 1H), 6.84 (d, J = 8.8 Hz, 2H), 3.70 (s, 3H), 1.55 (s, 6H). 13C-NMR (101 MHz, DMSO) δ 174.7, 155.7, 146.5, 132.7, 128.7, 126.7, 126.1, 122.3, 113.9, 55.5, 47.5, 27.3.
N-Benzyl-3-methylbenzamide (3q): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 7.61 (s, 1H), 7.57 (s, 1H), 7.39–7.26 (m, 7H), 6.56 (s, 1H), 4.61 (d, J = 5.7 Hz, 2H), 2.37 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 167.6, 138.4, 138.3, 134.3, 132.2, 128.7, 128.4, 127.9, 127.7, 127.5, 123.9, 44.1, 21.3.
N-Hexyl-3-methylbenzamide (3r): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 7.51 (s, 1H), 7.49–7.42 (m, 1H), 7.20 (d, J = 4.7 Hz, 2H), 6.30 (s, 1H), 3.44–3.27 (m, 2H), 2.29 (s, 3H), 1.58–1.44 (m, 2H), 1.32–1.16 (m, 6H), 0.87–0.75 (m, 3H). 13C-NMR (101 MHz, CDCl3) δ 167.8, 138.2, 134.8, 131.9, 128.3, 127.7, 123.8, 40.1, 31.5, 29.6, 26.6, 22.5, 21.3, 14.0.
N-(Benzo[d][1,3]dioxol-5-yl)-3-methylbenzamide (3s): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 7.54 (s, 1H), 7.49–7.42 (m, 1H), 7.28–7.24 (m, 2H), 6.81–6.60 (m, 3H), 6.26 (s, 1H), 3.64 (q, J = 6.6 Hz, 2H), 2.83 (t, J = 6.9 Hz, 2H), 2.37 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ 167.7, 147.9, 146.2, 138.4, 134.6, 132.6, 132.1, 128.4, 127.6, 123.7, 121.7, 109.1, 108.3, 100.9, 41.3, 35.4, 21.3.
N-Cyclohexyl-3-methylbenzamide (3t): White solid. 1H-NMR (400 MHz, Chloroform-d) δ 7.57 (s, 1H), 7.55–7.48 (m, 1H), 7.35–7.27 (m, 2H), 5.93 (s, 1H), 4.05–3.90 (m, 1H), 2.40 (s, 3H), 2.10–1.96 (m, 2H), 1.84–1.56 (m, 4H), 1.52–1.35 (m, 2H), 1.29–1.18 (m, 2H). 13C-NMR (101 MHz, CDCl3) δ 166.8, 138.2, 135.1, 131.8, 128.3, 127.6, 123.8, 48.6, 33.1, 25.5, 24.9, 21.3.
3-Methyl-N-(octan-2-yl)benzamide (3u): Colorless oil. 1H-NMR (400 MHz, Chloroform-d) δ 7.59 (s, 1H), 7.54 (t, J = 4.6 Hz, 1H), 7.26 (d, J = 4.6 Hz, 2H), 6.53 (s, 1H), 3.36 (td, J = 6.2, 2.0 Hz, 2H), 2.35 (s, 3H), 1.65–1.48 (q, J = 6.1 Hz, 1H), 1.42–1.23 (m, 8H), 0.98–0.80 (m, 6H). 13C-NMR (101 MHz, CDCl3) δ 167.9, 138.2, 134.9, 131.9, 128.3, 127.7, 123.8, 43.0, 39.4, 31.0, 28.9, 24.3, 23.0, 21.3, 14.0, 10.8.
Tert-Butyl quinolin-8-ylcarbamate (3v): Brown solid. 1H-NMR (400 MHz, Chloroform-d) δ 9.05 (s, 1H), 8.82 (dd, J = 4.1, 2.1 Hz, 1H), 8.44 (d, J = 7.6 Hz, 1H), 8.16 (d, J = 8.3 Hz, 1H), 7.54 (t, J = 8.0 Hz, 1H), 7.45 (d, J = 7.8 Hz, 2H), 1.60 (s, 9H).13C-NMR (101 MHz, CDCl3) δ 152.94, 148.00, 138.24, 136.30, 135.18, 128.07, 127.38, 121.56, 120.18, 114.42, 80.45, 28.43.
8-Aminequinoline (3x): Pale yellow solid. 1H-NMR (400 MHz, DMSO-d6) δ 8.73 (dt, J = 3.7, 1.8 Hz, 1H), 8.18 (dt, J = 8.3, 1.8 Hz, 1H), 7.46 (ddd, J = 8.3, 4.2, 1.9 Hz, 1H), 7.30 (td, J = 7.9, 1.8 Hz, 1H), 7.06 (dd, J = 8.1, 2.2 Hz, 1H), 6.87 (d, J = 7.6 Hz, 1H), 5.94 (s, 2H). 13C-NMR (101 MHz, DMSO) δ 147.43, 145.68, 137.84, 136.31, 129.02, 128.07, 121.91, 114.12, 109.09.

5. Conclusions

In summary we reported a mild, one-pot Pd catalyzed transamidation of 8-aminoquinoline. The mind and facile Boc protection activate the amide C(acyl)–N bond by twisting its geometry to lower the amidic resonance energy for facile Pd oxidative addition. This strategy gives a new choice in removal of directing groups after the C-H functionalization.

Supplementary Materials

Supplementary Materials are available online.

Author Contributions

J.Y. and R.Y. conceived and designed the experiments; W.W., H.X., and S.L. performed the experiments; W.W. and J.Y. checked and analyzed the data; J.Y. wrote the paper; R.Y. revised the manuscript; all authors read and approved the final manuscript.

Funding

This research was funded by the National Natural Science Foundation of China (Grant No. 21602017), the Natural Science Foundation of Jiangsu Province (Grant No. BK20160405), the University Science Research Project of Jiangsu Province (16KJB150001), and the Research Start-up Fund of Changshu Institute of Technology (No. XZ1508).

Conflicts of Interest

The authors declare no conflict of interests.

References

  1. Shilov, A.E.; Shul’pin, G.B. Activation of C-H bonds by metal complexes. Chem. Rev. 1997, 97, 2879–2932. [Google Scholar] [CrossRef]
  2. He, J.; Wasa, M.; Chan, K.S.L.; Shao, Q.; Yu, J.-Q. Palladium Catalyzed Transformations of Alkyl C−H Bonds. Chem. Rev. 2017, 117, 8649–8709. [Google Scholar] [CrossRef] [PubMed]
  3. Park, Y.; Kim, Y.; Chang, S. Transition Metal-Catalyzed C−H Amination: Scope, Mechanism, and Applications. Chem. Rev. 2017, 117, 9247–9301. [Google Scholar] [CrossRef] [PubMed]
  4. Dong, Z.; Ren, Z.; Thompson, S.J.; Xu, Y.; Dong, G. Transition-Metal-Catalyzed C−H Alkylation Using Alkenes. Chem. Rev. 2017, 117, 9333–9403. [Google Scholar] [CrossRef] [PubMed]
  5. Chen, M.S.; White, M.C. A predictably selective aliphatic C-H oxidation reaction for complex molecule synthesis. Science 2007, 318, 783–787. [Google Scholar] [CrossRef]
  6. Qin, Y.; Zhu, L.; Luo, S. Organocatalysis in Inert C−H Bond Functionalization. Chem. Rev. 2017, 117, 9433–9520. [Google Scholar] [CrossRef]
  7. Abrams, D.J.; Provenchera, P.A.; Sorensen, E.J. Recent applications of C–H functionalization in complex natural product synthesis. Chem. Soc. Rev. 2018, 47, 8925–8967. [Google Scholar] [CrossRef]
  8. Shi, H.; Herron, A.N.; Shao, Y.; Shao, Q.; Yu, J.-Q. Enantioselective remote meta-C-H arylation and alkylation via a chiral transient mediator. Nature 2018, 558, 581–585. [Google Scholar] [CrossRef]
  9. Murai, S.; Kakiuchi, F.; Sekine, S.; Tanaka, Y.; Kamatani, A.; Sonoda, M.; Chatani, N. Efficient catalytic addition of aromatic carbon-hydrogen bonds to olefins. Nature 1993, 366, 529–531. [Google Scholar] [CrossRef]
  10. Kimura, N.; Kochi, T.; Kakiuchi, F. Iron-Catalyzed Regioselective Anti-Markovnikov Addition of C–H Bonds in Aromatic Ketones to Alkenes. J. Am. Chem. Soc. 2017, 139, 14849–14852. [Google Scholar] [CrossRef]
  11. Xiao, B.; Gong, T.-J.; Xu, J.; Liu, Z.-J.; Liu, L. Palladium-Catalyzed Intermolecular Directed C−H Amidation of Aromatic Ketones. J. Am. Chem. Soc. 2011, 133, 1466–1474. [Google Scholar] [CrossRef] [PubMed]
  12. Xiao, B.; Fu, Y.; Xu, J.; Gong, T.-J.; Dai, J.-J.; Yi, J.; Liu, L. Pd(II)-Catalyzed C−H Activation/Aryl−Aryl Coupling of Phenol Esters. J. Am. Chem. Soc. 2010, 132, 468–469. [Google Scholar] [CrossRef] [PubMed]
  13. Trost, B.M.; Imi, K.; Davies, I.W. Elaboration of Conjugated Alkenes Initiated by Insertion into a Vinylic C-H Bond. J. Am. Chem. Soc. 1995, 117, 5371–5372. [Google Scholar] [CrossRef]
  14. Li, G.; Wan, L.; Zhang, G.; Leow, D.; Spangler, J.; Yu, J.-Q. Pd(II)-Catalyzed C–H Functionalizations Directed by Distal Weakly Coordinating Functional Groups. J. Am. Chem. Soc. 2015, 137, 4391–4397. [Google Scholar] [CrossRef] [Green Version]
  15. Huang, L.; Hackenberger, D.; Goossen, L.J. Iridium-Catalyzed ortho-Arylation of Benzoic Acids with Arenediazonium Salts. Angew. Chem. Int. Ed. 2015, 54, 12607–12611. [Google Scholar] [CrossRef]
  16. Biafora, A.; Krause, T.; Hackenberger, D.; Belitz, F.; Goossen, L.J. ortho-C−H Arylation of Benzoic Acids with Aryl Bromides and Chlorides Catalyzed by Ruthenium. Angew. Chem. Int. Ed. 2016, 55, 14752–14755. [Google Scholar] [CrossRef] [PubMed]
  17. Dastbaravardeh, N.; Toba, T.; Farmer, M.E.; Yu, J.-Q. Monoselective o-C–H Functionalizations of Mandelic Acid and α-Phenylglycine. J. Am. Chem. Soc. 2015, 137, 9877–9884. [Google Scholar] [CrossRef]
  18. Gao, P.; Guo, W.; Xue, J.J.; Zhao, Y.; Yuan, Y.; Xia, Y.Z.; Shi, Z.Z. Iridium(III)-Catalyzed Direct Arylation of C-H Bonds with Diaryliodonium Salts. J. Am. Chem. Soc. 2015, 137, 12231–12240. [Google Scholar] [CrossRef] [PubMed]
  19. Yang, W.; Ye, S.; Fanning, D.; Coon, T.; Schmidt, Y.; Krenitsky, P.; Stamos, D.; Yu, J.-Q. Orchestrated Triple C-H Activation Reactions Using Two Directing Groups: Rapid Assembly of Complex Pyrazoles. Angew. Chem. Int. Ed. 2015, 54, 2501–2504. [Google Scholar] [CrossRef] [PubMed]
  20. Boerth, J.A.; Ellman, J.A. A Convergent Synthesis of Functionalized Alkenyl Halides through Cobalt(III)-Catalyzed Three-Component C–H Bond Addition. Angew. Chem. Int. Ed. 2017, 56, 9976–9980. [Google Scholar] [CrossRef]
  21. Ikemoto, H.; Kanai, M.; Tanaka, R.; Yoshino, T.; Matsunaga, S.; Sakata, K.; Sakata, K.; Yoshino, T.; Matsunaga, S. Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*CoIII-Catalyzed C–H Alkenylation/Directing Group Migration Sequence. Angew. Chem. Int. Ed. 2017, 56, 7156–7160. [Google Scholar] [CrossRef] [PubMed]
  22. Tran, L.D.; Daugulis, O. Nonnatural Amino Acid Synthesis by Using Carbon–Hydrogen Bond Functionalization Methodology. Angew. Chem. Int. Ed. 2012, 51, 5188–5191. [Google Scholar] [CrossRef]
  23. Zaitsev, V.G.; Shabashov, D.; Daugulis, O. Highly Regioselective Arylation of sp3 C−H Bonds Catalyzed by Palladium Acetate. J. Am. Chem. Soc. 2005, 127, 13154–13155. [Google Scholar] [CrossRef] [PubMed]
  24. Feng, Y.; Chen, G. Total Synthesis of Celogentin C by Stereoselective C–H Activation. Angew. Chem. Int. Ed. 2010, 49, 958–961. [Google Scholar] [CrossRef]
  25. Shabashov, D.; Daugulis, O. Auxiliary-Assisted Palladium-Catalyzed Arylation and Alkylation of sp2 and sp3 Carbon−Hydrogen Bonds. J. Am. Chem. Soc. 2010, 132, 3965–3972. [Google Scholar] [CrossRef] [PubMed]
  26. Ano, Y.; Tobisu, M.; Chatani, N. Palladium-Catalyzed Direct Ethynylation of C(sp3)–H Bonds in Aliphatic Carboxylic Acid Derivatives. J. Am. Chem. Soc. 2011, 133, 12984–12986. [Google Scholar] [CrossRef]
  27. Gutekunst, W.R.; Gianatassio, R.; Baran, P.S. Sequential Csp3–H Arylation and Olefination: Total Synthesis of the Proposed Structure of Pipercyclobutanamide A. Angew. Chem. Int. Ed. 2012, 51, 7507–7510. [Google Scholar] [CrossRef]
  28. Shibata, K.; Chatani, N. Rhodium-catalyzed regioselective addition of the ortho C–H bond in aromatic amides to the C–C double bond in α,β-unsaturated γ-lactones and dihydrofurans. Chem. Sci. 2016, 7, 240–245. [Google Scholar] [CrossRef] [PubMed]
  29. Shibata, K.; Natsui, S.; Chatani, N. Rhodium-Catalyzed Alkenylation of C–H Bonds in Aromatic Amides with Alkynes. Org. Lett. 2017, 19, 2234–2237. [Google Scholar] [CrossRef]
  30. Yang, Y.; Hou, W.; Qin, L.; Du, J.; Feng, H.; Zhou, B.; Li, Y. Rhodium-Catalyzed Directed Sulfenylation of Arene C–H Bonds. Chem.–Eur. J. 2014, 20, 416–420. [Google Scholar] [CrossRef]
  31. Shan, C.; Luo, X.; Qi, X.; Liu, S.; Li, Y.; Lan, Y. Mechanism of Ruthenium-Catalyzed Direct Arylation of C–H Bonds in Aromatic Amides: A Computational Study. Organometallics 2016, 35, 1440–1445. [Google Scholar] [CrossRef]
  32. Aihara, Y.; Tobisu, M.; Fukumoto, Y.; Chatani, N. Ni(II)-Catalyzed Oxidative Coupling between C(sp2)–H in Benzamides and C(sp3)–H in Toluene Derivatives. J. Am. Chem. Soc. 2014, 136, 15509–15512. [Google Scholar] [CrossRef]
  33. Aihara, Y.; Chatani, N. Nickel-Catalyzed Direct Arylation of C(sp3)–H Bonds in Aliphatic Amides via Bidentate-Chelation Assistance. J. Am. Chem. Soc. 2014, 136, 898–901. [Google Scholar] [CrossRef] [PubMed]
  34. Aihara, Y.; Chatani, N. Nickel-Catalyzed Direct Alkylation of C–H Bonds in Benzamides and Acrylamides with Functionalized Alkyl Halides via Bidentate-Chelation Assistance. J. Am. Chem. Soc. 2013, 135, 5308–5311. [Google Scholar] [CrossRef] [PubMed]
  35. Wu, X.; Zhao, Y.; Ge, H. Direct Aerobic Carbonylation of C(sp2)–H and C(sp3)–H Bonds through Ni/Cu Synergistic Catalysis with DMF as the Carbonyl Source. J. Am. Chem. Soc. 2015, 137, 4924–4927. [Google Scholar] [CrossRef]
  36. Wu, X.; Zhao, Y.; Ge, H. Nickel-Catalyzed Site-Selective Alkylation of Unactivated C(sp3)–H Bonds. J. Am. Chem. Soc. 2014, 136, 1789–1792. [Google Scholar] [CrossRef] [PubMed]
  37. Yi, J.; Yang, L.; Xia, C.; Li, F. Nickel-Catalyzed Alkynylation of a C(sp2)–H Bond Directed by an 8-Aminoquinoline Moiety. J. Org. Chem. 2015, 80, 6213–6221. [Google Scholar] [CrossRef] [PubMed]
  38. Kubo, T.; Chatani, N. Dicumyl Peroxide as a Methylating Reagent in the Ni-Catalyzed Methylation of Ortho C–H Bonds in Aromatic Amides. Org. Lett. 2016, 18, 1698–1701. [Google Scholar] [CrossRef] [PubMed]
  39. Zhang, J.; Li, D.; Chen, H.; Wang, B.; Liu, Z.; Zhang, Y. Copper(II)/Silver(I)-Catalyzed Sequential Alkynylation and Annulation of Aliphatic Amides with Alkynyl Carboxylic Acids: Efficient Synthesis of Pyrrolidones. Adv. Synth. Catal. 2016, 358, 792–807. [Google Scholar] [CrossRef]
  40. Takamatsu, K.; Hirano, K.; Masahiro, M. Copper-Mediated Decarboxylative Coupling of Benzamides with ortho-Nitrobenzoic Acids by Directed C–H Cleavage. Angew. Chem. Int. Ed. 2017, 56, 5353–5357. [Google Scholar] [CrossRef]
  41. Liu, J.; Yu, L.; Zhuang, S.; Gui, Q.; Chen, X.; Wang, W.; Tan, Z. Copper-mediated ortho C–H sulfonylation of benzoic acid derivatives with sodium sulfinates. Chem. Commun. 2015, 51, 6418–6421. [Google Scholar] [CrossRef] [PubMed]
  42. Williamson, P.; Galvan, A.; Gaunt, M.J. Cobalt-catalysed C–H carbonylative cyclisation of aliphatic amides. Chem. Sci. 2017, 8, 2588–2591. [Google Scholar] [CrossRef] [PubMed]
  43. Zhang, J.; Chen, H.; Lin, C.; Liu, Z.; Wang, C.; Zhang, Y. Cobalt-Catalyzed Cyclization of Aliphatic Amides and Terminal Alkynes with Silver-Cocatalyst. J. Am. Chem. Soc. 2015, 137, 12990–12996. [Google Scholar] [CrossRef]
  44. Zhang, Z.-Z.; Han, Y.-Q.; Zhan, B.-B.; Wang, S.; Shi, B.-F. Synthesis of Bicyclo[n.1.0]alkanes by a Cobalt-Catalyzed Multiple C(sp3)–H Activation Strategy. Angew. Chem. Int. Ed. 2017, 56, 13145–13149. [Google Scholar] [CrossRef]
  45. Shang, R.; Ilies, L.; Nakamura, E. Iron-Catalyzed Directed C(sp2)–H and C(sp3)–H Functionalization with Trimethylaluminum. J. Am. Chem. Soc. 2015, 137, 7660–7663. [Google Scholar] [CrossRef]
  46. Shang, R.; Ilies, L.; Asako, S.; Nakamura, E. Iron-Catalyzed C(sp2)–H Bond Functionalization with Organoboron Compounds. J. Am. Chem. Soc. 2014, 136, 14349–14352. [Google Scholar] [CrossRef] [PubMed]
  47. Ilies, L.; Matsubara, T.; Ichikawa, S.; Asako, S.; Nakamura, E. Iron-Catalyzed Directed Alkylation of Aromatic and Olefinic Carboxamides with Primary and Secondary Alkyl Tosylates, Mesylates, and Halides. J. Am. Chem. Soc. 2014, 136, 13126–13129. [Google Scholar] [CrossRef] [PubMed]
  48. Shang, R.; Ilies, R.; Matsumoto, A.; Nakamura, E. β-Arylation of Carboxamides via Iron-Catalyzed C(sp3)–H Bond Activation. J. Am. Chem. Soc. 2013, 135, 6030–6032. [Google Scholar] [CrossRef] [PubMed]
  49. Trost, B.M.; Fleming, I. Comprehensive Organic Synthesis; Pergamon Press: Oxford, UK, 1991. [Google Scholar]
  50. Zhang, S.-Y.; Li, Q.; He, G.; Nack, W.A.; Chen, G. Stereoselective Synthesis of -Alkylated -Amino Acids via Palladium-Catalyzed Alkylation of Methylene C(sp3)−H Bonds. J. Am. Chem. Soc. 2013, 135, 12135–12141. [Google Scholar] [CrossRef]
  51. Deguchi, T.; Xin, H.-L.; Morimoto, H.; Ohshima, T. Direct Catalytic Alcoholysis of Unactivated 8-Aminoquinoline Amides. ACS Catal. 2017, 7, 3157–3161. [Google Scholar] [CrossRef]
  52. He, G.; Zhang, S.-Y.; Nack, W.A.; Chen, G. Use of a Readily Removable Auxiliary Group for the Synthesis of Pyrrolidones by the Palladium-Catalyzed Intramolecular Amination of Unactivated C(sp3)−H Bonds. Angew. Chem. Int. Ed. 2013, 52, 11124–11128. [Google Scholar] [CrossRef] [PubMed]
  53. Spletstoser, J.T.; White, J.M.; Tunoori, A.R.; Georg, G.I. Mild and Selective Hydrozirconation of Amides to Aldehydes Using Cp2Zr(H)Cl:  Scope and Mechanistic Insight. J. Am. Chem. Soc. 2007, 129, 3408–3419. [Google Scholar] [CrossRef]
  54. Boit, T.B.; Weires, N.A.; Kim, J.; Garg, N.K. Nickel-Catalyzed Suzuki–Miyaura Coupling of Aliphatic Amides. ACS Catal. 2018, 8, 1003–1008. [Google Scholar] [CrossRef]
  55. Dander, J.E.; Baker, E.L.; Garg, N.K. Nickel-Catalyzed Transamidation of Aliphatic Amide Derivatives. Chem. Sci. 2017, 8, 6433–6438. [Google Scholar] [CrossRef] [PubMed]
  56. Weires, N.A.; Caspi, D.D.; Garg, N.K. Kinetic Modeling of the Nickel-Catalyzed Esterification of Amides. ACS Catal. 2017, 7, 4381–4385. [Google Scholar] [CrossRef]
  57. Medina, J.M.; Moreno, J.; Racine, S.; Du, S.; Garg, N.K. Mizoroki–Heck Cyclizations of Amide Derivatives for the Introduction of Quaternary Centers. Angew. Chem. Int. Ed. 2017, 56, 6567–6571. [Google Scholar] [CrossRef] [PubMed]
  58. Dander, J.E.; Garg, N.K. Breaking Amides Using Nickel Catalysis. ACS Catal. 2017, 7, 1413–1423. [Google Scholar] [CrossRef] [PubMed]
  59. Hie, L.; Baker, E.L.; Anthony, S.M.; Desrosiers, J.-N.; Senanayake, C.; Garg, N.K. Nickel-Catalyzed Esterification of Aliphatic Amides. Angew. Chem. Int. Ed. 2016, 55, 15129–15132. [Google Scholar] [CrossRef] [Green Version]
  60. Dander, J.E.; Weires, N.A.; Garg, N.K. Benchtop Delivery of Ni(cod)2 using Paraffin Capsules. Org. Lett. 2016, 18, 3934–3936. [Google Scholar] [CrossRef] [PubMed]
  61. Baker, E.L.; Yamano, M.M.; Zhou, Y.; Anthony, S.M.; Garg, N.K. A Two-Step Approach to Achieve Secondary Amide Transamidation Enabled by Nickel Catalysis. Nat. Commun. 2016, 7, 1–5. [Google Scholar] [CrossRef]
  62. DerivativesSimmons, B.J.; Weires, N.A.; Dander, J.E.; Garg, N.K. Nickel-Catalyzed Alkylation of Amide. ACS Catal. 2016, 6, 3176–3179. [Google Scholar]
  63. Weires, N.A.; Baker, E.L.; Garg, N.K. Nickel-Catalysed Suzuki–Miyaura Coupling of Amides. Nat. Chem. 2016, 8, 75–79. [Google Scholar] [CrossRef]
  64. Hie, L.; Nathel, N.F.F.; Shah, T.K.; Baker, E.L.; Hong, X.; Yang, Y.-F.; Liu, P.; Houk, K.N.; Garg, N.K. Conversion of Amides to Esters by the Nickel-Catalysed Activation of Amide C–N Bonds. Nature 2015, 524, 79–83. [Google Scholar] [CrossRef]
  65. Ra Liu, C.; Shi, S.; Liu, Y.; Liu, R.; Lalancette, R.; Szostak, R.; Szostak, M. The Most Twisted Acyclic Amides: Structures and Reactivity. Org. Lett. 2018, 20, 7771–7774. [Google Scholar] [CrossRef]
  66. Shi, S.; Nolan, S.P.; Szostak, M. Well-Defined Palladium(II)-NHC (NHC = N-Heterocyclic Carbene) Precatalysts for Cross-Coupling Reactions of Amides and Esters by Selective Acyl CO–X (X = N, O) Cleavage. Acc. Chem. Res. 2018, 51, 2589–2599. [Google Scholar] [CrossRef]
  67. Li, G.; Szostak, M. Highly Selective Transition-Metal-Free Transamidation of Amides and Amidation of Esters at Room Temperature. Nature Commun. 2018, 9, 4165. [Google Scholar] [CrossRef] [PubMed]
  68. Liu, C.; Li, G.; Shi, S.; Meng, G.; Lalancette, R.; Szostak, R.; Szostak, M. Acyl and Decarbonylative Suzuki Coupling of N-Acetyl Amides: Electronic Tuning of Twisted, Acyclic Amides in Catalytic Carbon−Nitrogen Bond Cleavage. ACS Catal. 2018, 8, 9131–9139. [Google Scholar] [CrossRef]
  69. Li, G.; Lei, P.; Szostak, M. Transition-Metal-Free Esterification of Amides via Selective N−C Cleavage under Mild Conditions. Org. Lett. 2018, 20, 5622–5625. [Google Scholar] [CrossRef] [PubMed]
  70. Szostak, R.; Szostak, M. N-Acyl-Glutarimides: Resonance and Proton Affinities of Rotationally-Inverted Twisted Amides Relevant to N−C(O) Cross-Coupling. Org. Lett. 2018, 20, 1342–1345. [Google Scholar] [CrossRef] [PubMed]
  71. Meng, G.; Shi, S.; Lalancette, R.; Szostak, R.; Szostak, M. Reversible Twisting of Primary Amides via Ground State N−C(O) Destabilization: Highly Twisted Rotationally Inverted Acyclic Amides. J. Am. Chem. Soc. 2018, 140, 727–734. [Google Scholar] [CrossRef]
  72. Meng, G.; Szostak, M. Site-Selective C−H/C−N Activation by Cooperative Catalysis: Primary Amides as Arylating Reagents in Directed C−H Arylation. ACS Catal. 2017, 7, 7251–7256. [Google Scholar] [CrossRef]
  73. Shi, S.; Szostak, M. Pd–PEPPSI: A General Pd–NHC Precatalyst for Buchwald–Hartwig Cross-Coupling of Esters and Amides (Transamidation) under the Same Reaction Conditions. Chem. Commun. 2017, 53, 10584–10587. [Google Scholar] [CrossRef] [PubMed]
  74. Lei, P.; Meng, G.; Shi, S.; Ling, Y.; An, J.; Szostak, R.; Szostak, M. Suzuki–Miyaura Cross-Coupling of Amides and Esters at Room Temperature: Correlation with Barriers to Rotation around C–N and C–O Bonds. Chem. Sci. 2017, 8, 6525–6530. [Google Scholar] [CrossRef] [PubMed]
  75. Meng, G.; Szostak, R.; Szostak, M. Suzuki−Miyaura Cross-Coupling of N-Acylpyrroles and Pyrazoles: Planar, Electronically Activated Amides in Catalytic N–C Cleavage. Org. Lett. 2017, 19, 3596–3599. [Google Scholar] [CrossRef] [PubMed]
  76. Meng, G.; Lei, P.; Szostak, M. A General Method for Two-Step Transamidation of Secondary Amides Using Commercially Available, Air- and Moisture-Stable Palladium/NHC (N-Heterocyclic Carbene) Complexes. Org. Lett. 2017, 19, 2158–2161. [Google Scholar] [CrossRef]
  77. Liu, Y.; Shi, S.; Achtenhagen, M.; Liu, R.; Szostak, M. Metal-Free Transamidation of Secondary Amides via Selective N–C Cleavage under Mild Conditions. Org. Lett. 2017, 19, 1614–1617. [Google Scholar] [CrossRef]
  78. Lei, P.; Meng, G.; Szostak, M. General Method for the Suzuki-Miyaura Cross-Coupling of Amides Using Commercially Available, Air- and Moisture-Stable Palladium/NHC (NHC = N-Heterocyclic Carbene) Complexes. ACS Catal. 2017, 7, 1960–1965. [Google Scholar] [CrossRef]
  79. Shi, S.; Szostak, M. Nickel-Catalyzed Diaryl Ketone Synthesis by N–C Cleavage: Direct Negishi Cross-Coupling of Primary Amides by Site- Selective N,N-Di-Boc Activation. Org. Lett. 2016, 18, 5872–5875. [Google Scholar] [CrossRef] [PubMed]
  80. Meng, G.; Shi, S.; Szostak, M. Palladium-Catalyzed Suzuki−Miyaura Cross-Coupling of Amides via Site-Selective N−C Bond Cleavage by Cooperative Catalysis. ACS Catal. 2016, 6, 7335–7339. [Google Scholar] [CrossRef]
  81. Pace, V.; Holzer, W.; Meng, G.; Shi, S.; Lalancette, R.; Szostak, R.; Szostak, M. Structures of Highly Twisted Amides Relevant to Amide N−C Cross-Coupling: Evidence for Ground-State Amide Destabilization. Chem. Eur. J. 2016, 22, 14494–14498. [Google Scholar] [CrossRef] [PubMed]
  82. Shi, S.; Meng, G.; Szostak, M. Synthesis of Biaryls via Nickel Catalyzed Suzuki–Miyaura Coupling of Amides by Carbon–Nitrogen Cleavage. Angew. Chem. Int. Ed. 2016, 55, 6959–6963. [Google Scholar] [CrossRef] [PubMed]
  83. Meng, G.; Szostak, M. Sterically-Controlled Pd-Catalyzed Chemoselective Ketone Synthesis via N–C Cleavage in Twisted Amides. Org. Lett. 2015, 17, 4364–4367. [Google Scholar] [CrossRef]
  84. Di Gioia, M.L.; Gagliardi, A.; Leggio, A.; Leotta, V.; Romio, E.; Liguori, A. N-Urethane protection of amines and amino acids in an ionic liquid. RSC Adv. 2015, 5, 63407–63420. [Google Scholar] [CrossRef]
  85. Nardi, M.; Cano, N.H.; Costanzo, P.; Oliverio, M.; Sindona, G.; Procopio, A. Aqueous MW eco-friendly protocol for amino group protection. RSC Adv. 2015, 5, 18751. [Google Scholar] [CrossRef]
  86. Durga, T.V.; Rambabu, A.; Reddy, M.S.; Babu, B.H. Ionic Liquid as Efficient Reaction Medium for N-tert-Boc Protection of Amines. Asian J. Chem. 2017, 29, 1313–1316. [Google Scholar]
  87. Sunitha, S.; Kanjilal, S.; Reddy, P.S.; Prasad, R.B.N. An efficient and chemoselective Brønsted acidic ionic liquid-catalyzed N-Boc protection of amines. Tetrahedron Lett. 2008, 49, 2527–2532. [Google Scholar] [CrossRef]
  88. Schwarzer, M.C.; Konno, R.; Hojo, T.; Ohtsuki, A.; Nakamura, K.; Yasutome, A.; Takahashi, H.; Shimasaki, T.; Tobisu, M.; Chatani, N.; et al. Combined Theoretical and Experimental Studies of Nickel-Catalyzed Cross-Coupling of Methoxyarenes with Arylboronic Esters via C–O Bond Cleavage. J. Am. Chem. Soc. 2017, 139, 10347–10358. [Google Scholar] [CrossRef] [PubMed]
  89. Schaub, T.; Fischer, P.; Steffen, A.; Braun, T.; Radius, U.; Mix, A. C−F Activation of Fluorinated Arenes using NHC-Stabilized Nickel(0) Complexes: Selectivity and Mechanistic Investigations. J. Am. Chem. Soc. 2008, 130, 9304–9317. [Google Scholar] [CrossRef] [PubMed]
Sample Availability: All samples are available from authors.
Molecules 24 01234 sch001 550
Scheme 1. Amide directing groups (DGs) in C–H activation, removal methods, and our design.
Scheme 1. Amide directing groups (DGs) in C–H activation, removal methods, and our design.
Molecules 24 01234 sch001
Molecules 24 01234 g001 550
Figure 1. New strategy to remove 8-aminoquinoline (8-AQ).
Figure 1. New strategy to remove 8-aminoquinoline (8-AQ).
Molecules 24 01234 g001
Molecules 24 01234 g002 550
Figure 2. Scope of the transamidation reaction. Conditions: see Supplementary Materials for details.
Figure 2. Scope of the transamidation reaction. Conditions: see Supplementary Materials for details.
Molecules 24 01234 g002
Molecules 24 01234 g003 550
Figure 3. Scope of alkyl amines. a Reaction temperature 25 °C, b 80 °C.
Figure 3. Scope of alkyl amines. a Reaction temperature 25 °C, b 80 °C.
Molecules 24 01234 g003
Molecules 24 01234 sch002 550
Scheme 2. Gram-scale reaction and recovery of 8-AQ.
Scheme 2. Gram-scale reaction and recovery of 8-AQ.
Molecules 24 01234 sch002
Table
Table 1. Optimization of removal of 8-AQ.
Table 1. Optimization of removal of 8-AQ.
Molecules 24 01234 i001
a Conditions: amide (0.2 mmol), amine (1.5 equiv), yield determined by mesitylene as an internal standard. b 8-AQ amide (0.2 mmol), 4-dimethylaminopyridine (DMAP) (1.1 equiv), di-tert-butyl decarbonate (Boc2O) (1.2 equiv), and CH3CN (0.1 M) were reacted for 12 h. c Isolated yield.

Share and Cite

MDPI and ACS Style

Wu, W.; Yi, J.; Xu, H.; Li, S.; Yuan, R. An Efficient, One-Pot Transamidation of 8-Aminoquinoline Amides Activated by Tertiary-Butyloxycarbonyl. Molecules 2019, 24, 1234. https://doi.org/10.3390/molecules24071234

AMA Style

Wu W, Yi J, Xu H, Li S, Yuan R. An Efficient, One-Pot Transamidation of 8-Aminoquinoline Amides Activated by Tertiary-Butyloxycarbonyl. Molecules. 2019; 24(7):1234. https://doi.org/10.3390/molecules24071234

Chicago/Turabian Style

Wu, Wengang, Jun Yi, Huipeng Xu, Shuangjun Li, and Rongxin Yuan. 2019. "An Efficient, One-Pot Transamidation of 8-Aminoquinoline Amides Activated by Tertiary-Butyloxycarbonyl" Molecules 24, no. 7: 1234. https://doi.org/10.3390/molecules24071234

APA Style

Wu, W., Yi, J., Xu, H., Li, S., & Yuan, R. (2019). An Efficient, One-Pot Transamidation of 8-Aminoquinoline Amides Activated by Tertiary-Butyloxycarbonyl. Molecules, 24(7), 1234. https://doi.org/10.3390/molecules24071234

Article Metrics

Back to TopTop