Asosiy tarkibga oʻtish Elsevier logotipi
Download 24.06 Kb.
|
Document(5)-WPS Office
|
Asosiy tarkibga oʻtish Elsevier logotipi Fenilpiridin Sianobifenil birligi piridin guruhining 4-pog'onasida bog'langan modifikatsiyalangan 2-fenilpiridin hosilalari yordamida yangi orto-platinlangan metallomozogenlar 105 olindi. Kimdan: Kimyo, molekulyar fanlar va kimyo muhandisligi bo'yicha mos yozuvlar moduli , 2021 Tegishli shartlar:
8.17.2.3.2 Gomoleptik va geteroleptik Iridium (III) komplekslarining barqarorligi va izomeriyasi Ppy tipidagi ligandlar assimetrik bo'lgani uchun ularning iridiy (III) komplekslari ikkita izomerga ega bo'lishi mumkin - yuz ( fac ) va meridional ( mer ). Bu izomerlar turli xil fotofizik xususiyatlarga ega. Masalan, [ fac -Ir(ppy) 3 ] yuqori emissiya kvant rentabelligi 40% ni tashkil etadi, mer -[Ir(ppy) 3 ] esa 3,6% emissiya kvant rentabelligini, 87 va ularning emissiya l max va emissiya muddatini ko'rsatadi. har xil. Shunga o'xshash topilmalar ppy tipidagi ligandlarni o'z ichiga olgan ko'pgina iridiy (III) komplekslarining izomerlari uchun ham xabar qilingan. 88Hozirgacha OLED-larda ishlatiladigan siklometallangan iridiy (III) komplekslarining aksariyati yuz izomerlaridir. Yuz izomeri termodinamik mahsulot, meridional izomer esa kinetik mahsulot bo'lib, merdan fak-izomerga o'tishga yuqori haroratlarda (> 200 °C) 87-89 yoki fotoreaktsiya 43 orqali erishish mumkin ( 4-rasm ). Biroq, sof yuz heteroleptik iridiy (III) komplekslarini oddiy vositalar bilan tayyorlash qiyin. 90 Geteroleptik iridiy (III) komplekslarining ba’zi cis-mer-izomerlari ularning N , N ga qaraganda kamroq emissiya kvant hosildorligini ko‘rsatadi.-trans-mer-izomer analoglari. Sis-mer-izomer yanada barqaror tur bo'lganligi sababli, izomerlar aralashmasi odatda vakuum-cho'ktirish usuli yordamida ishlab chiqarilgan OLED-larda mavjud; sof N , N -trans-mer-izomer ishlatilganda ham ( 5-rasm ). 91 , 92 Bu muhim masala bo'lib, iridiy (III) komplekslari bilan ishlab chiqarilgan OLEDlar uchun eritmani vakuumda cho'ktirishdan ko'ra yaxshiroq ishlov berishni hisobga oladi. Toʻliq oʻlchamdagi rasmni yuklab olish uchun tizimga kiring 4-rasm . Iridium (III) ppy tipidagi komplekslarning meridional va yuz izomerlarining tuzilishi va fotoreaktsiya yo'li bilan meridional izomerni yuz izomeriga aylantirish reaktsiyasi sxemasi. Reprinted with permission from Ragni, R.; Plummer, E. A.; Brunner, K.; Hofstraat, J. W.; Babudri, F.; Farinola, G. M.; Naso, F.; Cola, L. D. J. Mater. Chem. 2006, 16, 1161–1170. Copyright 2006, Royal Society of Chemistry. Sign in to download full-size image
Recently, Baranoff et al. reported a study on the stability of the blue phosphorescent [FIrPic] (41) and related iridium(III) complexes.93 They found that picolinate or acetylacetonate ligands can be easily detached from iridium(III) in solution upon the addition of Lewis acids. As protons could be present in the emissive layer, their study gave a possible rationale for the observed degradation of phosphorescent iridium(III) dopant in OLEDs (Figure 6). Sign in to download full-size image Figure 6. Acid-induced degradation of iridium(III) complexes in solution. Reprinted with permission from Baranoff, E.; Curchod, B. F. E.; Frey, J.; Scopelliti, R.; Kessler, F.; Tavernelli, I.; Rothlisberger, U.; Grätzel, M.; Nazeeruddin, M. K. Inorg. Chem. 2012, 51, 215–224. Copyright 2012, American Chemical Society. Six-membered Rings with One Heteroatom and Fused Carbocyclic Derivatives Nicholas Dennis, in Comprehensive Heterocyclic Chemistry II, 1996 5.03.3.2 Aryl Groups A review of the nitration of phenyl-substituted heterocycles has been published 〈93AHC(58)215〉. Electrophilic substitution of phenylpyridines occurs exclusively in the phenyl ring, as expected. 4-Phenylpyridine, for example, yields mononitration products in the ratio o : m : p, 20 : 33 : 47 〈68JCS(B)862, 71JCS(B)712〉. However, the 4-phenyl-1,4-dihydropyridine (84) on nitration with sulfuric acid and sodium nitrate yields exclusively the 4-nitrophenyl derivative in 56–72% yield (Equation (35)) 〈87KGS68〉. The nitration, sulfonation, and bromination of 1-phenylpyridinium cations occurs in the meta-position of the 1-phenyl group 〈86H(24)2545〉. 2-Phenylquinoline-8-carboxylic acid (85) is nitrated with fuming nitric acid to produce the 2-(4-nitrophenyl) derivative, which crystallizes from solution (Equation (36)) 〈89JMC396〉. The charged quinolinium system exhibits a marked electron-withdrawing power, as shown by the nitration of 1-methyl-2-phenylquinolinium metho-sulfate (86) by nitric acid to yield the 1-methyl-2-(3-nitrophenyl)quinolinium salt (97%) (Equation (37)) 〈30JCS2236〉. The activating and para-directing influence of an N-oxide group toward electrophilic substitution does not extend to phenyl substituents; thus, 2-phenylpyridine 1-oxide (87) is nitrated primarily in the meta-position (Equation (38)) 〈58JCS1754〉 as is 2-phenylquinoline N-oxide 〈77CPB1256〉. (35)
(39)
Six-membered Rings with One Heteroatom, and their Fused Carbocyclic Derivatives V. Caprio, in Comprehensive Heterocyclic Chemistry III, 2008 7.03.3.2 Aryl Groups Much of the recent research on phenylpyridines has focused on studying the regioselective functionalization of the phenyl ring via pyridine-directed ortho-lithiation and C–H bond activation. 2-Phenylpyridine undergoes nucleophilic attack of the organolithium when using n-BuLi or t-BuLi while lithiation at C-2 occurs using the superbase n-BuLi-lithium dimethylaminoalkoxide (LiDMAE) <2003JOC2028>. Lithiation at the phenyl ring does occur when the C-2 position of the pyridine moiety is blocked with a chlorine atom. Lithiation of 2-chloro-6-phenylpyridine using t-BuLi in Et2O/cumene at −78 °C leads to selective lithiation at the C-2′ position of the phenyl ring <2003JOC4918>. No lithium–chlorine exchange or lithiation ortho to the chlorine atom is observed. Treatment of 2-chloro-6-phenylpyridine with t-BuLi results in ortho-lithiation via coordination of the pyridine nitrogen and chlorine atom with the lithiating reagent. The metallated species is stabilized by chelation with nitrogen and reacts with a variety of electrophiles. For instance, quenching the reaction with Bu3SnCl gives stannane 62 in 51% yield (Scheme 12). Sign in to download full-size image Scheme 12. Regioselective lithiation at the phenyl group of 2-phenylpyridines is also possible in the presence of unsubstituted pyridine rings when there are additional directing groups on the phenyl ring. Lithiation of 2(3-fluorophenyl)pyridines and 2(3-chlorophenylpyridines) at C-2 of the phenyl ring occurs under kinetic control using n-BuLi in THF at −75 °C and also be can effected under thermodynamic control on the corresponding bromide, albeit in low yield, using lithium 2,2,6,6-tetramethylpiperidide (LTMP) in THF at −75 °C <2004JOC6766>. In the latter example, the stabilizing effect of the nitrogen atom prevents the elimination of lithium bromide to give a benzyne. In this study the directing effect of the pyridine moiety was shown to be weaker than that of a fluorine atom. Lithiation of 2-(3-fluorophenyl)pyridine with n-BuLi followed by quenching with iodine gives the C-2′ iodinated product (Equation 43) while lithiation of 2(4-fluorophenyl)pyridine with the superbase n-BuLi-t-BuOK (LICKOR) followed by an iodine quench results in iodination at the C-3′ position (Equation 44). (43)
The 2-pyridyl moiety can be used to direct regioselective catalytic C–H bond activation. Chelate-directed electrophilic aromatic substitution of 2-phenylpyridine with 5 mol% Pd(OAc)2 leads to the formation of a palladacycle 63 that undergoes oxidation with PhI(OAc)2 followed by carbon–heteroatom bond formation and reductive elimination to give acetylated phenol 64 <2004JA2300> (Scheme 13). Use of 2.3–2.5 equiv of oxidant leads to dioxygenation in 83% yield. This palladium-catalyzed C–H bond activation can also be applied to the formation of C–C bonds ortho to the 2-pyridyl moiety. Treatment of palladacycle 63 with [Ph2I]BF4 leads to arylation at the C-2′-position of the benzene ring <2005JA7330>. The 2-quinolyl group also functions as a directing group in this transformation. Sign in to download full-size image Scheme 13. These palladacycles also undergo addition to iodobenzenes. 2-Phenylpyridine is arylated at the ortho-position with para-substituted iodobenzenes in good yield in the presence of 5 mol% Pd(OAc)2 and stoichiometric amounts of AgOAc <2005OL3657>. The 2-pyridyl substituent also directs C–H bond cleavage by rhodium and ruthenium complexes to give cyclometallated hydride complexes that undergo further organometallic reactions. Reaction of 2-phenylpyridine with the rhodium complex formed in situ from [(C8H14)2RhCl]2 and tricyclohexylphosphine proceeds via insertion of rhodium across the ortho C–H bond to give a hydride complex 65. Hydrometallation of alkenes followed by reductive elimination gives alkylated products in moderate to good yield (Scheme 14).
Sign in to download full-size image Scheme 14. A similar process, performed using the ruthenium complex Ru3(CO)12 in the presence of ethene and carbon monoxide, leads to the formation of C-2′ propionylated products <1997JOC2604>. This process fails when applied to the coupling of other alkenes and, at present, is limited to the use of ethene. Arylation ortho to the pyridyl group in 2-phenylpyridines and 2-naphthylpyridines occurs in the presence of 2.5 mol% [RuCl2(ή6-C6H6)]2 and aryl bromides to give ortho aryl products in high yield. In this case the reaction is postulated to proceed via SEAr reaction of an arylated ruthenium(iv) complex, formed in situ, to give a ruthenacycle that undergoes reductive elimination to yield the product. The 2-pyridyl group also directs activation of neighboring benzylic C–H bonds. Treatment of 2-(2,6-dimethylphenyl)pyridines with Ru3(CO)12 and triethylsilane in the presence of norbornene as a hydrogen acceptor in toluene leads to silylation at the benzylic position. The reaction is enhanced by the presence of electron-donating groups on the pyridine ring. For example, 2-(2,6-dimethylphenyl)-4-methoxypyridine undergoes silylation at both benzylic positions to give the product in 85% yield (Equation 45). (45)
(46)
Sign in to download full-size image Scheme 15. Microbial oxidation of phenylpyridines and phenylquinolines occurs selectively at the benzene ring to give catechols. Treatment of 2-phenylpyridine, 2-benzylpyridine, and 2-phenylquinoline with Escherichia coli cells expressing genes for biphenyl dioxygenase and dihydrodiol dehydrogenase results in oxidation of the benzene ring to give the 2,3-diol in low yield <2005T195>. Ring Synthesis
2,4-Diphenylpyridine187 To a solution of 2-phenylpyridine-N-oxide (100 mg, 0.58 mmol) in dry THF (20 mL) was added dropwise PhMgCl (0.35 mL, 0.7 mmol) at −78 °C. The resulting red mixture was stirred at −78 °C for 10 min, whereupon MeOH (35 μL, 0.87 mmol) was added resulting in a change of colour to yellow. After warming up the reaction mixture to rt, trifluoroacetic anhydride (TFAA) was added and stirred for 20 min at rt. The reaction was quenched with aqueous NaOH (1 M, 3 mL), extracted twice with mixture of heptane/Et2O/EtOAc (8:3:2) and once with brine, dried (Na2SO4) and concentrated. The residue was subjected to column chromatography and elution with ethyl acetate/heptane (1:9) gave, after co-concentration from CH2Cl2 2,4-diphenylpyridine as a yellowish oil (102 mg, 76%). Possible Anti-Parkinson’s Disease Therapeutics From Nature: A Review Abhijit Dey, ... Jitendra Nath De, in Studies in Natural Products Chemistry, 2015 Chrysanthemum morifolium (Ramat.) Tzvel., Chrysanthemum indicum L. (Asteraceae) The water extract of C. morifolium inhibited MPP+-induced cytotoxicity in human SH-SY5Y neuroblastoma cells by reducing ROS and elevating Bax/Bcl-2 ratio [258]. Methanol extract of another species C. indicum has shown its potential anti-PD activity by protecting MPP+-induced damage in SH-SY5Y cells and LPS-stimulated BV-2 microglial cells possibly by preventing neuronal apoptosis and neuroinflammatory NF-κB/IκB-α signaling [259]. Furthermore, anti-inflammatory activity of C. indicum was ascribed to its ability to inhibit NO, PGE2, TNF-α, and IL-1β, MAPKs, and NF-κB signaling pathways [260]. Experiments for Introduction of Mechanochemistry in the Undergraduate Curriculum Davor Margetić, Vjekoslav Štrukil, in Mechanochemical Organic Synthesis, 2016 9.2.2.2 2-(2,6-Diiodophenyl)pyridine (8) Procedure: A mixture of 2-phenylpyridine (6) (54.3 mg, 0.349 mmol), N-iodosuccinimide (7) (172.8 mg, 0.768 mmol), AgSbF6 (48.07 mg, 0.139 mmol, 0.4 equiv.), and [Cp∗RhCl2]2 (5) (10.81 mg, 0.017 mmol, 5.0 mol%) was milled in a 10 mL stainless steel milling jar with one 10 mm stainless steel ball in a Retsch MM400 mixer mill at 30 Hz for 3 h. After the milling was completed, the product was isolated by column chromatography using silica and a mixture of pentane:EtOAc (v:v = 15:1) as eluent (Scheme 9.3). Sign in to download full-size image Scheme 9.3. Csingle bondH functionalization of 2-phenylpyridine. Off-white solid, m.p. > 123–125°C; 1H NMR (600 MHz, CDCl3): δ = 8.75 (ddd, 1H, J = 4.8, 1.1, 1.0 Hz), 7.92 (d, 2H, J = 8.1 Hz), 7.81 (dt, 1H, J = 7.7, 1.8 Hz), 7.34 (ddd, 1H, J = 7.7, 5.0, 1.1 Hz), 7.25 (dt, 1H, J = 7.8, 1.0 Hz), 6.74 (t, 1H, J = 8.0 Hz); 13C NMR (150 MHz, CDCl3): δ = 164.4, 149.5, 148.4, 139.2, 136.7, 131.3, 124.2, 123.4, 97.0; IR (KBr): ν = 2923, 2328, 1748, 1560, 1405, 1265, 1179, 991, 757 cm−1. Introduction of Water-Solubility in Palladacycles and Their Catalytic Applications
2.3 2-Arylheterocycle-Derived Palladacycles 2-Arylheterocycles, such as 2-phenylpyridine, are common ligands for palladacyclic complexes. This class of palladacycles are easily prepared and highly robust. The 2-arylheterocycle provides a modular base for introducing water-solubilizing functionality. Wu reported a palladacycle derived from a sulfonated 2-arylnaphthoxazole ligand (8, Fig. 4.2) (14). The 2-arylnaphthoxazole ligand is easily prepared by condensation of benzaldehyde derivatives with 1-amino-2-naphthol (Scheme 4.15) (35). Complex 8 (0.1 mol%) is an effective catalyst for the Suzuki coupling of aryl bromides in water at room temperature. Moderate to good yields were achieved with challenging heteroaryl bromide substrates. Complex 8 shows low activity for coupling of unactivated aryl chlorides. The authors did not report efforts to recycle the aqueous catalyst solution or the level of palladium leaching into the organic products. Scheme 4.15 Sign in to download full-size image Scheme 4.15. Synthesis of sulfonated 2-arylnaphthoxazole palladacycle 8. Copper-catalyzed cycloaddition of PEG azide and an aryl alkyne provides an efficient entry to PEG-modified 4-aryltriazole ligands (Scheme 4.16) (15). Metalation with palladium affords complex 9, which showed high productivity for Suzuki couplings of aryl iodides, bromides, and chlorides in water at 100°C. High conversion is achieved with palladium loadings as low as 1 × 10–4 mol% (9.8 × 105 turnovers). Addition of elemental mercury completely deactivated the catalyst, suggesting that complex 9 decomposes to palladium nanoparticles, which act as the active catalyst. A wide range of aryl bromides were coupled with TONs ranging from 103 to 105. Notably, 2- and 3-bromopyridine was coupled using 1 × 10–3 mol% palladium. Complex 9 (1 × 10–4 mol% Pd) showed modest recyclability. Yields above 90% were achieved for three cycles, after which they dropped dramatically. Reaction times were doubled with each cycle indicating a loss of activity with each cycle. Although only a few cycles were achieved, the catalyst loading was much lower than other systems that report high yields over more cycles. Complex 9 also showed good activity for the Sonogashira coupling of aryl bromides and phenylacetylene in refluxing water. Scheme 4.16
Hydroxymethyl-substituted 2-arylpyrazine-derived palladacycles complexed to PPh3 (3, Fig. 4.2) or S-Phos (27, Scheme 4.17) are reported to be water-soluble (9). No data regarding the water-solubility is provided, however. The hydroxymethyl substituent would be expected to provide limited hydrophilic character, particularly with highly hydrophobic phosphine ligands coordinated. S-Phos-coordinated complex 27 (0.2 mol%) is effective for the Suzuki coupling of unactivated aryl chlorides in water. In contrast, Pd(OAc)2/S-Phos gave little conversion under the same conditions. Complex 27 is the only palladacycle system that has shown broad applicability to aryl chlorides in water. Complex 27 is also an effective catalyst for the Hartwig-Buchwald coupling of aryl chlorides and aniline derivatives in water at 100°C. Buchwald has reported on-water amination of aryl chlorides using a hydrophobic palladacycle coordinated to X-phos (36). Scheme 4.17
4-Ferrocenylpyridimine-based palladacycle 14 (Fig. 4.4) does not have any hydrophilic substituents on the organic ligand (19). Rather the water-solubility is provided by the charge separated cationic palladium center. Complex 14 (0.5 mol%) is an effective catalyst for the Suzuki coupling of aryl bromides in water at 100°C. Unactivated aryl chlorides give low conversion unless tricyclohexylphosphine (PCy3) is added to the reaction system. The combination of 14 and PCy3 affords a 78% yield for the coupling of 4-chlorotoluene and 4-hydroxymethylphenylboronic acid. Other Five-membered Rings with Three or more Heteroatoms, and their Fused Carbocyclic Derivatives
6.12.5.8 Reaction with radicals, transition-metal complexes and reduction Reaction of organoiridium(III)-2-phenylpyridine complex, [Ir(ppy)2(μ-Cl)]2 (ppy = 2-phenylpyridinato-C2,N), with 4-(2-bromophenyl)-1,2,3-selenadiazole (179b) in CH2Cl2 yields [Ir(ppy)2Cl(179b)] (189) in 61% yield (Scheme 48). The intramolecular Se ⋯ Cl types of chalcogen bond was found in the structure of 189.103 Scheme 48 Sign in to download full-size image Scheme 48. Kinzhalov, M. A.; Popova, E. A.; Petrov, M. L.; Khoroshilova, O. V.; Pombeiro, A. J. L. Inorg. Chim. Acta 2018, 477, 31–33. A Ru(II) complex, [Ru(bpy)2L](ClO4)2 (bpy = 2,2′-bipyridine, L = 93) 190 was synthesized in 15% yield by reacting 93 with Ru(bpy)2Cl2·2H2O in (CH)2(OH)2/H2O (9:1 v/v) at 130 °C (Scheme 49).104,105 Its G-quadruplex DNA-binding properties were investigated. Scheme 49 Sign in to download full-size image Scheme 49. Yuan, F.; Chen, X.; Zhou, Y.; Yang, F.; Zhang, Q.; Liu, J. J. Coord. Chem. 2012, 65, 1246–1257; Li, Q.; Sun, D.; Zhou, Y.; Liu, D.; Zhang, Q.; Liu, J. Inorg. Chem. Commun. 2012, 20, 142–146. A selenium-containing ruthenium complex Ru(phtpy)(L)Cl(ClO4) (phtpy = 4-phenyl-2,2′:6′,2″-terpyridine, L = 93) 191 has been synthesized and found to be able to enhance radiation-induced DNA damage through superoxide overproduction.106 Complex 191 was synthesized by refluxing the same quantity of Ru(phtpy)Cl3 with ligand 93 in ethanol for 6 h (Scheme 50). Scheme 50 Sign in to download full-size image Scheme 50. Deng, Z.; Yu, L.; Cao, W.; Zheng, W.; Chen, T. Chem. Commun. 2015, 51, 2637–2640. A mutifunctional ruthenium (Ru)-based conjugate was designed and synthesized. The Ru complex with favorable bioimaging function was covalently linked with a cancer-targeted molecule that could be effectively internalized by the tumor to realize enhanced theranostic effects.107 Cis-[Ru(II) (L)2Cl2] 192 was prepared by reacting RuCl3·3H2O with L (93) in DMF at 140 °C for 6 h in 59% yield. [Ru(II)(L)2(L1)](ClO4)2 193 and [Ru(II)(L)2(Bioben)](ClO4)2 194 were prepared by the reaction of ligand L1 (2-pyridin-2-yl-1H-benzoimidazol) or Bioben (1 equiv) with cis-[Ru(II)(L)2Cl2] 192 (1 equiv) in deoxygenated solution (2-methoxyethanol/H2O = 3:1), under reflux for 6 h, in 44% and 37% yields, respectively (Scheme 51). Scheme 51 Sign in to download full-size image Scheme 51. Zhao, Z.; Gao, P.; You, Y.; Chen, T. Chem. Eur. J. 2018, 24, 3289–3298. Reaction of chloro-bridged dimer Ir2(btp)4Cl2 with 1 equiv. of 93 in a 2:1 solution of methanol/CH2Cl2, followed by the addition of a methanol NH4PF6 solution, iridium(III) complex [Ir(btp)2(L)]+·PF6− (195, where btp = 2-(2-pyridyl)benzothiophene and L = 93) was obtained in 66% yield (Scheme 52).108 The single crystal of 195 was obtained and analyzed to study the molecular packing structure. The aggregation-induced phosphorescent emission (AIPE) properties of 195 was described. Moreover, the use of an AIPE iridium(III) complex for specific mitochondrial imaging and tracking in living cells was demonstrated. Scheme 52 Sign in to download full-size image Scheme 52. Chen, Y.; Qiao, L.; Yu, B.; Li, G.; Liu, C.; Ji, L.; Chao, H. Chem. Commun. 2013, 49, 11095. The complex tris-(thenoyltrifluoroacetonate)([1,2,5]selenadiazolo[3,4-f][1,10] phenanthroline) europium(III) acetonitrile solvate, [Eu(TTA)3L]1.5CH3CN (L = 93) 196 was synthesized from Eu(NO3)3·5H2O, 2-thenoyltrifluoroacetone (TTA) and 93, in the presence of sodium hydroxide in ethanol, at 50 °C, in 87% yield.50 The Eu(III) ion reacted with 2-thenoyltrifluoroacetone (TTA) in a reaction of 1:3 and one molecule of the bidentate nitrogen donor ligand (93) and the structure established by single-crystal X-ray diffraction (Scheme 53). The complex 196 emits the characteristic red light, both in solution and in thermally evaporated films. Scheme 53 Sign in to download full-size image Scheme 53. Gallardo, H.; Braga, H. C.; Tuzimoto, P.; Bortoluzzi, A.; Salla, C. A. M.; Bechtold, I. H.; Martins, J. S.; Legnani, C.; Quirino, W. G. Inorg. Chim. Acta 2018, 473, 75–82. As described in CHEC-II2 and CHEC-III,3 reduction of 2,1,3-benzoselenadiazoles was widely used to obtain o-phenylenediamines. 1,2-Diamino-4-[(4′-hydroxymethyl)-phenyl]-benzene 198 was obtained by reduction of 5-[(4′-hydroxymethyl)-phenyl]-benzo[1,2,5]selenadiazole (197) by zinc and acetic acid (Scheme 54).109 Scheme 54
Li, M.; Lincoln, P. J. Inorg. Biochem. 2009, 103, 963–970. A highly selective ratiometric fluorescent probe 199, which contains an aminonaphthalimide fluorophore, a self-immolative spacer and 2,1,3-benzoselenadiazol for 1,4-dithiothreitol (DTT) detection was designed.110 The probe 199 displays a 66 nm red-shift of fluorescence emission and the color changes from colorless to jade-green upon reaction with 1,4-dithiothreitol (DTT). The reaction mechanism was suggested as shown in Scheme 55. Scheme 55 Sign in to download full-size image Scheme 55. Zhu, B.; Zhang, X.; Jia, H.; Li, Y.; Liu, H.; Tan, W. Org. Biomol. Chem. 2010, 8, 1650–1654. An electrochemical probe of benzo[1,2,5]selenadiazole 45 containing a Se − N bond was developed for the determination of glutathione (GSH) (Scheme 56).111 The cyclic voltammogram of the scanned at 100 mV/s displayed an irreversible reduction peak at − 0.106 V (vs Ag/AgCl electrode) and a significant peak current decrease could be further provoked with the addition of GSH into the solution of 45. The relatively low detection limit and a broad dynamic range were achieved. Scheme 56 Sign in to download full-size image Scheme 56. Wang, W.; Li, L.; Liu, S. F.; Ma, C. P.; Zhang, S. S. J. Am. Chem. Soc. 2008, 130, 10846–10847. A naphthalene derivate containing [1,2,5]selenadiazole 200 has been developed as an example of colorimetric and ratiometric fluorescent probes for glutathione (GSH) at physiologically relevant concentration (Scheme 57).112 Scheme 57 Sign in to download full-size image Scheme 57. Zeng, X.; Zhang, X.; Zhua, B.; Jia, H.; Yang, W.; Li, Y.; Xue, J. Sens. Actuators B 2011, 159, 142–147. Reductive deselenation of 5,6,8,9,11,12-hexakis(4-tert-butylphenyl)-[1,2,5]selenadiazolo[3,4-b]porphyrazine H2PASe (201) by addition of hydrogen sulfide with formation of vicinal diamino porphyrazine was studied by spectral and kinetic methods (Scheme 58), and a mechanism involving two hydrosulfide ions was proposed.113 Scheme 58 Sign in to download full-size image Scheme 58. Kozlov, A. V.; Stuzhin, P. A. Russ. J. Org. Chem. 2013, 49, 913–921. Chemical reduction of 45 and 15 was performed, and thermally stable radical anion (RA) salts [K(THF)]+[45] •− (202) and [K(18-crown-6)]+[45] •− (203) were isolated (Scheme 59).114 On contact with air, RA [45]•− underwent fast decomposition in solution with the formation of anion [SeCN]−, which were isolated in the form of a salt [K(18-crown-6)]+[SeCN]− 204 (Scheme 60). In the case of 15, RA [15] •− was detected by EPR spectroscopy but not isolated. Instead, salt [K(18-crown-6)]22 +[15-Te2]2− (205) featuring an anionic complex with coordinate Te–Te bond was obtained. On contact with air, salt 205 was transformed to salt [K(18-crown-6)]22 +[15-Te4-15]2 − (206) containing an anionic complex with two coordinate Te–Te bonds (Scheme 61). Compound 206 was also obtained by treatment of 15 with [K(18-crown-6)]22 +[Te4]2 in 46% yield. The structures of 202–206 were confirmed by X-ray diffraction, and the nature of the Te–Te coordinate bond in [15-Te2]2− and [15-Te4-15]2 − was studied by DFT calculations and QTAIM analysis. Scheme 59 Sign in to download full-size image Scheme 59. Pushkarevsky, N. A.; Chulanova, E. A.; Shundrin, L. A.; Smolentsev, A. I.; Salnikov, G. E.; Pritchina, E. A.; Genaev, A. M.; Irtegova, I. G.; Bagryanskaya, I. Y.; Konchenko, S. N.; Gritsan, N. P.; Beckmann, J.; Zibarev. A. V. Chem. Eur. J. 2019, 25, 806–816. Scheme 60 Sign in to download full-size image Scheme 60. Pushkarevsky, N. A.; Chulanova, E. A.; Shundrin, L. A.; Smolentsev, A. I.; Salnikov, G. E.; Pritchina, E. A.; Genaev, A. M.; Irtegova, I. G.; Bagryanskaya, I. Y.; Konchenko, S. N.; Gritsan, N. P.; Beckmann, J.; Zibarev. A. V. Chem. Eur. J. 2019, 25, 806–816. Scheme 61 Sign in to download full-size image Scheme 61. Pushkarevsky, N. A.; Chulanova, E. A.; Shundrin, L. A.; Smolentsev, A. I.; Salnikov, G. E.; Pritchina, E. A.; Genaev, A. M.; Irtegova, I. G.; Bagryanskaya, I. Y.; Konchenko, S. N.; Gritsan, N. P.; Beckmann, J.; Zibarev. A. V. Chem. Eur. J. 2019, 25, 806–816. High-Valent Cobalt-Catalyzed CH Bond Functionalization Tatsuhiko Yoshino, Shigeki Matsunaga, in Advances in Organometallic Chemistry, 2017 2.2.1 Addition to Polar Unsaturated Bonds Matsunaga and Kanai reported an addition reaction of 2-phenylpyridine to sulfonyl-protected imines using [Cp*Co(C6H6)](PF6)2 as a catalyst (Scheme 6).60 The same reaction was reported by the Ellman group and the Shi group using Cp*Rh(III) catalysts,68–71 and the catalytic cycle was proposed based on the Cp*Rh(III)-catalyzed reaction (Fig. 4). The coordinated benzene dissociates and is replaced with 2-phenylpyridine to afford I. Csingle bondH metalation is assumed to proceed via aromatic electrophilic substitution or CMD mechanism assisted by another 2-phenylpyridine as a base (II). Coordination of an imine (III), insertion of the Csingle bondN double bond (IV), and subsequent protonation of V by another 2-phenylpyridine or a pyridinium salt liberates the product. The scope of this reaction was expanded to 2-pyrimidyl-protected indoles (Scheme 7).72 The addition of a catalytic amount of KOAc improved the yield in this case. The addition to the Csingle bondN double bond of ketenimines was also achieved by Lu and Wang (Scheme 8).73 The products are easily converted to pyrroloindolones by treatment with EtONa. Ackermann reported aminocarbonylation directed by pyrazoles (Scheme 9A).74 In situ generation of isocyanates using acylazides as a reactant affords the same products. Ellman independently reported the same reaction under slightly different reaction conditions (Scheme 9B).75 Scheme 6
Scheme 6. Csingle bondH bond addition of 2-phenylpyridine to sulfonyl-protected imines. Fig. 4
Fig. 4. Proposed catalytic cycle for Csingle bondH bond addition of 2-phenylpyridine to sulfonyl-protected imines. Scheme 7
Scheme 7. Csingle bondH bond addition of pyrimidyl-protected indoles to imines. Scheme 8
Scheme 8. Csingle bondH bond addition to ketenimines. Scheme 9
Scheme 9. Csingle bondH bond addition to isocyanates. In contrast to Csingle bondN double bonds, Csingle bondH bond addition reactions to Csingle bondO double bonds of aldehydes are rather difficult because such reactions are thermodynamically unfavorable unless destabilized and highly electrophilic aldehydes are used.76 Li reported the addition of pyrimidyl-protected indoles and pyrroles to ethyl glyoxylate (Scheme 10),77 which is the only example of a simple Csingle bondH bond addition reaction to a Csingle bondO double bond under Cp*Co(III) catalysis. Scheme 10
The reversibility and thermodynamic problems are overcome by a cascade reaction. Ellman reported Csingle bondH bond addition/dehydrative cyclization cascade reactions using aldehydes.63 Azobenzenes afford indazoles (Scheme 11A), and α,β-unsaturated oxime ethers afford furans (Scheme 11B) in the presence of aldehydes, [Cp*Co(C6H6)][B(C6F5)4]2, and AcOH. Zeng reported a similar dehydrative condensation that affords indolizines (Scheme 11C).78 Csingle bondH bond addition products, secondary alcohols, are transient reaction intermediates in these reactions, and dehydrative cyclization proceeds under acidic reaction conditions. Scheme 11
A 1,4-addition to α,β-unsaturated carbonyl compounds is thermodynamically more favorable than 1,2-addition and thus is expected to be more successful under proton-transfer, reversible reaction conditions. Matsunaga and Kanai reported addition reactions of 2-phenylpyridines to enones and α,β-unsaturated N-acylpyrroles (Scheme 12A).60 The products of α,β-unsaturated N-acylpyrroles are converted to corresponding esters and an amide. Li reported addition reactions of indoles, pyrroles, and other aromatic Csingle bondH bonds to enals and enones under mild reaction conditions (Scheme 12B).77 Maleimides also work as electrophiles, as reported by Zhang (Scheme 12C).79 Scheme 12
In the 1,4-addition reactions to α,β-unsaturated carbonyl compounds, oxa-π-allylcobalt species would be generated as intermediates, and they would be in equilibrium with nucleophilic cobalt enolates. Ellman achieved diastereoselective three-component reactions in which the enolates generated after 1,4-addition work as nucleophiles to aldehydes and chiral sulfinylimines (Scheme 13).80 Cp*Rh(III)-catalyzed conditions produced only the 1,4-addition product, indicating higher reactivity of the cobalt enolate compared with that of the rhodium enolate. Scheme 13
Pyridines and their Benzo Derivatives: (v) Synthesis G. Jones, in Comprehensive Heterocyclic Chemistry, 1984 2.08.3.3.3 Pyrroles, indoles and carbazoles Pyrolysis of alkylpyrroles gives pyridines. Pictet obtained 3-phenylpyridine (702) from N-benzylpyrrole, quinoline from 2-methylindole (703), isoquinoline from N-methylisoindolin-1-one (704), and phenanthridine (705) from N-methylcarbazole 〈05CB1946〉. Flash vacuum pyrolysis of the oxindoles (706) gives quinol-2-ones; the mechanism suggested involves homolytic cleavage 〈73AJC369〉. Radicals are also thought to be involved in the pyrolytic conversion of methyl- and benzyl-indoles to quinolines 〈75JOC1511〉. More generally useful are the reactions of pyrroles or of indoles with carbenes to give pyridines or quinolines. The mechanism of addition of dichlorocarbene is illustrated in the formation of the pyridines (707). References to earlier work on additions to pyrroles are given in a paper that illustrates the greatly improved yields of 3-chloropyridines (707; equation 78a) that can be obtained if neutral (thermal decomposition of trichloroacetate) rather than strongly basic conditions are used for the dichlorocarbene generation 〈69JCS(C)2249〉. Sign in to download full-size image (78a) The mechanism of formation of quinolines from indoles is similar (equation 79) 〈64JCS938〉. The byproduct is an indolenine (708), thought to arise by reaction between the indolyl anion and dichlorocarbene. The phase transfer catalyzed procedure for generating carbenes can be applied to the reaction with pyrroles 〈76S798〉 and to indoles 〈76S249, 76S798〉. The reaction has been performed with chloroform and with bromoform (to give 3-bromoquinolines); chlorodifluoromethane gives mixtures of 3-chloro- and of 3-fluoro-quinolines although in reasonable yield only for the synthesis of compound (709) 〈79LA1456〉. A review lists other carbenes which have been used in attempted quinoline syntheses 〈77HC(32-1)232〉; monohalocarbenes obviously give quinolines without a 3-substituent. There is one example of the use of 18-crown-6 in the carbene preparation with an increase in yield over the phase transfer catalyst 〈76S249〉; in other cases there was no advantage. (79)
Sign in to download full-size image The 2-dichloromethylpyrrolenines (710) can be converted into pyridines by strong bases 〈69JCS(C)2555〉. The mechanism shown in equation (80) allows formation of 2- or of 4-ethoxymethylpyridines if a methyl group is available in position 2 or 4 of the pyrrole. The benzindoline (711) gives a mixture of benzo[h]quinoline and its tetrahydro derivative when heated in concentrated hydrochloric acid, presumably via the carbenium ion and a dihydrobenzoquinoline 〈72KGS1121〉. (80)
Sign in to download full-size image Ring expansion by diazoalkanes could involve carbene intermediates, but most mechanisms involve addition of the intact diazoalkane. The substrates are pyrrolones, indolones, isatins, or closely related species. The reactions can give mixtures, as in the reaction of pyrrole-2,3-diones where 3-hydroxypyrid-2-ones (719) and 4-hydroxypyrid-2-ones (720) are obtained 〈76LA1023〉. A number of examples of quinoline synthesis by diazoalkane ring expansion are given in a review 〈77HC(32-1)230〉; the suggested mechanism for expansion of oxindolylidene cyanoacetate is given in equation (81) 〈78JOC4383〉. Isatins can also give mixtures; 1-acetoxyisatin gives 3-hydroxyquinol-2-ones (721) with diazomethane or diazoethane, but a 4-hydroxyquinol-2-one (722) with diazopropane 〈69LA(725)37〉. Isatins react with enamino esters by the mechanism shown in equation (82) to give derivatives (723) of quinoline-3,4-dicarboxylic acid 〈71CB3341〉. The condensation products (724) from isatin and active methylene derivatives, react with alcohols in an acid- or base-catalyzed reaction, giving 3-cyanoquinoline-4-carboxylates (725) 〈76YZ33, 76CB723〉. The Pfitzinger synthesis (Section 2.08.2.2.2) is also relevant here, since isatins can be used to generate isatoic acids in situ. Sign in to download full-size image (81) Sign in to download full-size image (82) Sign in to download full-size image Some oxygenated indoles, and other indoles by oxidative procedures, can be transformed into quinolones. The hydroxyoxindole (726) is photochemically transformed into a 4-hydroxyquinol-2-one 〈70TL3163〉; a homolytic ring cleavage and recyclization is invoked. In the compounds (727) a carbenium ion site is generated by loss of nitrogen, then ring expansion gives the quinolylphosphine oxide 〈76LA225〉. From a 3-hydroxyindolin-2-one a 4-phosphoryl-3-hydroxypyrid-2-one is obtained in a similar reaction. A number of reactions are known in which an indole ring is oxidatively cleaved, then recyclized to a quinolone. Many of these reactions involve compounds with additional fused heterocyclic rings; the production of the 3-aminoquinol-2-one (728) provides a less complex example 〈79CPB551〉. Hypochlorite converts the tryptophan derivative (729) into 4-acetylquinol-2-one 〈67T687〉. When the dihydroxyindoline (730) is reduced a quinol-4-one is formed, via a spiro intermediate (731) 〈72BCJ2590〉. Treatment of the hydroxyisoindolones (732) with a diamine gives a 1-oxo-isoquinolin-3-carboxamide which can further cyclize to give an imidazoline or tetrahydropyrimidine substituent 〈71USP3594380〉. Isatins with imino ethers give 2-methoxyquinoline-4-carboxamides (733) as shown in equation (83), while amidines give 2-amino-4-carboxamides (734) 〈67LA(707)242〉. Isatogens react with phenylacetylenes to give quinol-4-ones, as shown in equation (84) 〈69JCS(C)2453〉. Sign in to download full-size image Sign in to download full-size image
Organometall kimyo jurnali Journal of Organometallic Chemistry Journal Koordinatsion kimyo sharhlari Coordination Chemistry Reviews Journal Organik elektronika Organic Electronics Journal Tetraedr Tetrahedron Journal Boshqa nashriyotlardan Tabiiy mahsulotlar tadqiqoti Tabiiy mahsulotlar tadqiqoti Jurnal Oltingugurt kimyosi jurnali Oltingugurt kimyosi jurnali Jurnal Polisiklik aromatik birikmalar Polisiklik aromatik birikmalar Jurnal Fizikaviy organik kimyo jurnali Fizikaviy organik kimyo jurnali Jurnal So'z belgisi bilan Elsevier logotipi ScienceDirect haqida Masofaviy kirish Xarid savati Reklama Aloqa va qo'llab-quvvatlash Foydalanish shartlari Maxfiylik siyosati Biz xizmatimizni taqdim etish va yaxshilash, kontent va reklamalarni moslashtirish uchun cookie-fayllardan foydalanamiz. Davom etish orqali siz cookie-fayllardan foydalanishga rozilik bildirasiz . Mualliflik huquqi © 2023 Elsevier BV yoki uning litsenziya egalari yoki hissa qo'shuvchilari. ScienceDirect® Elsevier BVning roʻyxatdan oʻtgan savdo belgisidir RELX guruhining bosh sahifasi Download 24.06 Kb. Do'stlaringiz bilan baham: 
|