carbon carbon bond formation friedel crafts alkylation

... the formation of a benzoylpalladium intermediate which either reacts with the alkynol or liberates benzoic acid; hence the formation of considerable amounts of the latter Carbon- carbon bond formation ... made with (Scheme 6.26) Carbon- carbon bond formation 227 Chemically modified were successfully used to accelerate the deprotection of various water insoluble allylic carbonates in genuine two-phase ... interest Carbon- carbon bond formation 221 Aqueous palladium-catalyzed Sonogashira coupling reactions were also applied for the preparation of polymers (see Chapter 7) 6.4 Allylic alkylations...

Ngày tải lên: 23/12/2013, 07:19

... phosphorus -carbon (P-C) bonds, which was a convenient method to generate structurally diversified organophosphorus compounds, provided many model reactions to develop the asymmetric P-C bonds formation ... acid 12 or under microwave conditions; 13 Among various methods to generate P-C bonds, the direct addition of P(O)-H bonds (dialkyl phosphonate [(RO)2P(O)H] or dialkyl phosphine oxides [R2R(O)H]) ... the asymmetric P-C bonds formation reactions There are several general methods to generate P-C bonds: (a) addition to unactivated olefins promoted by radical initiators or transition metals (b)...

Ngày tải lên: 14/09/2015, 08:38

... and Hb had a closer orientation in the stable conformation The conformation A was determined to be the major diastereoisomer Similar, the conformation B was determined to be the minor diastereoisomer ... phosphonates to α,β-unsaturated carbonyl compounds Tetramethylguanidine (TMG, 83) was found to be a good catalyst for the addition of dialkyl phosphonates to α,β-unsaturated carbonyl compounds (Scheme ... 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD, 92) provided a mild, rapid and efficient protocol to generate phosphorus carbon bonds The convenient procedure allowed a series of dialkyl alkylphosphonates (Scheme 2.2A) and...

Ngày tải lên: 14/09/2015, 08:38

... Chapter 3.1 Hydrogen bond donors catalyzed asymmetric reactions Electrophilic activation by small-molecule hydrogen bond donors has provided an important paradigam ... of this type of proton catalyst was that the bisamidine 148 cannot bind a single carbonyl group by two hydrogen bonds simultaneously because of the large distance between the amidinium groups ... found to increase the reaction rate of a series of reactions like Diels-Alder reaction and Friedel- Crafts reaction (Scheme 3.2) Enantioselectivities, however, remained constantly low even at...

Ngày tải lên: 14/09/2015, 08:38

Ngày tải lên: 14/09/2015, 08:38

... gained widespread application as efficient Lewis acid catalysts for carbon- carbon bond formation and organic synthetic transformations.42 40 For Reviews , see (a) Roush, W R Comprehensive Organic ... especially the design of novel chiral indium(III) complexes for catalytic enantioselective carbon- carbon bond formation and their application to the synthesis of bioactive molecules In this part of ... 1970s, considerable synthetic interest began to surface in the stereochemical control of carbon- carbon bond formation in the reactions of allylmetals with aldehydes and ketones This widespread use...

Ngày tải lên: 30/09/2015, 06:07

... dạng phản ứng Friedel Crafts hydrocarbon thơm với acid chloride anhydride Tác nhân điện tử acyl caton R-C+=O, sinh tác dụng acid lewis, tác nhân điện tử mạnh Phản ứng acyl hóa friedel- crafts xảy ... dò thêm hoạt tính xúc tác IRMOF-8 phản ứng acyl hóa Đây hướng đề tài 1.4.2 Phản ứng acyl hóa Friedel- Crafts Phản ứng acyl hóa có ý nghĩa thương mại quan trọng ngành sản xuất công nghiệp bước quan ... 2008 Michael A Miller cộng nghiên cứu khả hấp thụ khí H2 Pt/AC/BC/IRMOF-8, (AC activated carbon, BC amorphous carbon) , hình 1.37 [24] Hình 1.37: Hấp thụ khí H2 đẳng nhiệt Pt/AC/BC/IRMOF-8 298K [24]...

Ngày tải lên: 10/12/2013, 16:01

... PIId structure As mentioned, disulfide bond formation typically occurs prior to proteolytic processing in the trans-Golgi or secretory vesicles Thus, if disulfide bond pairing to form a heterodimeric ... under reducing and nonreducing conditions, Serrano et al [15] clearly demonstrated that disulfide bond formation among venom proteins, leading to multimeric structures, has a profound effect on venom ... two to three disulfide bonds being reported (Fig 3) (see also table of [5]) However, the PI adamalysin contains five cysteinyl residues, four of which are involved in disulfide bonds, leaving one free...

Ngày tải lên: 18/02/2014, 18:20

... Ile341–Arg347 peptide being involved in a disulfide bond The three peaks represent CID-based cleavage events at the cysteine b carbon sulfur bond, with double bond formation between the FEBS Journal 278 ... disulfide bond with free PDI cysteines Fig Disulfide bond formation between bacitracin and Cys345 on PDI (A) Scheme of thiol formation of the thiazoline ring of bacitracin A with subsequent formation ... disulfide bond formation We hypothesized that bacitracin may react with cysteines on PDI to form a disulfide bond Using MALDI-TOF ⁄ TOF MS analysis, we were able to show that disulfide bond formation...

Ngày tải lên: 14/03/2014, 23:20

... government works 2701 Cytoglobin conformations and disulfide bond formation heterogeneity of kinetics After breaking the S–S bond, the histidine relaxes towards a stable conformation, and kinetic curves ... government works 2697 Cytoglobin conformations and disulfide bond formation but not in a symmetrical way, as only one extremity is well defined in each subunit Thus, the conformational flexibility of both ... namely the role of the disulfide bond in protein function and its involvement in the tertiary and quaternary structures Cytoglobin conformations and disulfide bond formation A Results and Discussion...

Ngày tải lên: 15/03/2014, 11:20

... extend the information potential of the genetic code Thus, one genome can generate many – epigenomes – as the fertilized egg progresses through development and translates its information into ... equivalent increase in the number of protein coding genes Mechanisms other than DNA sequence information have been adopted during evolution to better index and regulate the various developmental ... utilized b-lactam antibiotics, and identifies features important for high affinity binding This information has been used in structure-based inhibitor design strategies aiming to combat MRSA resistance...

Ngày tải lên: 16/03/2014, 22:20

... trimer is stabilized through non-covalent interactions, and the formation of hexamer from trimer is facilitated by the disul®de bond formation between the subunits Sequence analysis con®rms the ... was examined by pore-limiting PAGE to examine the role of the metal ion, if any, in disul®de bond formation Native, cysteine-modi®ed and HgCl2-treated HABP1 were separated, transferred to nitrocellulose ... atmosphere of the experiment, in which unfolded monomer becomes dimer- ized through cysteine disul®de bond formation On the other hand, under reducing nondenaturing conditions, it is predominantly present...

Ngày tải lên: 17/03/2014, 17:20

... requiring conformational rearrangements in order to participate in peptide bond formation [3,5,6] These rearrangements are bound to consume time, which might explain the low rate of peptidyl bond formation ... flexibility The formation of the peptide bond The most significant biological implication of the two-fold rotation of the tRNA-3¢ end is the resulting geometry that should lead to peptide bond formation ... derived P-site, in green (Right) The chemical formulation of peptide bond formation Bottom: Our proposed mechanism for peptide bond formation Left: The 3¢ end of ASM (in blue) and the derived P-site...

Ngày tải lên: 23/03/2014, 17:22

... disulfide bond formation, with the resultant transfer of electrons to cytochrome c, generating water from oxygen through the action of cytochrome c oxidase This formation of disulfide bonds drives ... should be given to whether significant Protein folding and disulfide formation peroxide generation occurs during disulfide bond formation, an issue that has implications for cellular stress and hypoxia ... its domains [9] Calcium seems to compete with disulfide bond formation in the LDLR, and in the presence of this cation, non-native disulfide bonds predominate LDLR mutants that cause familial hypercholesterolaemia...

Ngày tải lên: 29/03/2014, 22:21

... organic transformations such as Knoevenagel condensation, aldol condensation, oxidation, epoxidation, hydrogenation, Suzuki cross-coupling, transesterification reaction, Friedel- Crafts alkylation, ... metal sites during the formation of MOF structures 3.2 Catalytic studies 3.2.1 Friedel- crafts acylation reaction CH3 CH3 CH3 O COCl + IRMOF-8 + O p-isomer o-isomer Scheme 3.1 Friedel- Craft acylation ... further research in the near future 1.3 Aim and objectives of the study The Friedel Craft acylation reaction Friedel Crafts acylation reactions of aromatic compounds with acid chlorides are considered...

Ngày tải lên: 10/05/2014, 21:59

... ‘‘direct’’ Friedel Crafts acylation reaction between acylium ion (Ph–C?=O) of TMPBA and sp2C–H of pyrene to give pyrene-g-(TMPBA)n (Scheme 1b) FT-IR was used as convenient tool to identify chemical bonds ... poly(phosphoric acid)/phosphorous pentoxide at 130 °C; b proposed mechanism of a ‘‘direct’’ Friedel Crafts acylation reaction between acylium ion (Ph–C?=O) of TMPBA and sp2C–H of pyrene 123 Nanoscale ... bisubstitution of TMPBA onto pyrene could be most likely occurred to pyrene via ‘‘direct’’ Friedel Crafts acylation reaction Although the mixture of pyrene-g-(TMPBA)n contains pyrene-g-(TMPBA)2...

Ngày tải lên: 21/06/2014, 17:20

... nghiên cứu đầy đủ hoạt tính xúc tác triflat kim loại với phản ứng Friedel- Crafts thơng thường, xúc tác cho phản ứng sulfonil hóa FriedelCrafts nghiên cứu, xoay quanh cation kim loại có hoạt tính biết ... 89  Khảo sát hoạt tính xúc tác triflat đất phản ứng sulfonil hóa Friedel- Crafts TỔNG QUAN 2.1 PHẢN ỨNG SULFONIL HĨA FRIEDEL- CRAFTS HỢP CHẤT HƯƠNG PHƯƠNG 2.1.1 Cơ chế phản ứng Hợp chất hương ... sulfonil hóa Friedel- Crafts 2.2.2 Phản ứng sulfonil hóa với xúc tác triflat O O S Cl + O M(OTf)n M(OTf)n O M(OTf)n S Cl S Cl O O O S + M(OTf)nCl O Phản ứng sulfonil hóa Friedel- Crafts có chất...

Ngày tải lên: 09/10/2014, 21:01

... ứng Friedel – Crafts ứng dụng MỤC LỤC PHẢN ỨNG ALKYL HÓA FRIEDEL – CRAFTS 1.1 1.2 Các yếu tố ảnh hưởng đến phản ứng alkyl hóa Friedel – Crafts 1.3 Cơ chế phản ứng alkyl hóa Friedel ... Friedel – Crafts Đặc điểm phản ứng alkyl hóa theo Friedel – Crafts PHẢN ỨNG ACYL HÓA FRIEDEL – CRAFTS 2.1 2.2 Các yếu tố ảnh hưởng đến phản ứng acyl hóa Friedel – Crafts ... ứng alkyl hóa Friedel – Crafts Khác với phản ứng alkyl hóa Friedel – Crafts, phản ứng acyl hóa Friedel – Crafts khả tạo sản phẩm nhiều lần Nguyên nhân sản phẩm phản ứng có chứa nhóm carbonyl hút...

Ngày tải lên: 12/04/2015, 14:26

... Tổng Quan Giới thiệu phản ứng Friedel- Crafts cổ điển Giới thiệu Hóa học Xanh Giới thiệu xúc tác triflat kim loại ứng dụng triflat kim loại vào phản ứng acil hóa Friedel- Crafts Giới thiệu vi sóng, ... trên, đề xuất mục tiêu nghiên cứu cho luận án tiến sĩ: Mục tiêu 1: Khảo sát phản ứng acil hóa Friedel- Crafts với nhiều tác chất khác - Tác chất clorur acid - Tác chất anhidrid acid - Tác chất acid ... xúc tác điều khảo sát thu hồi tái sử dụng Trong nội dung luận án nghiên cứu phản ứng acil hóa FriedelCrafts bao gồm loại phản ứng benzoil hóa, acetil hóa, propionil hóa butiril hóa Các sản phẩm...

Ngày tải lên: 28/05/2015, 16:17

... Ullmann reaction and decarboxylative cross-coupling reactions are green alternatives for the formation of C-C bonds between aromatic compounds These methods not require preformed organometallic reagents ... Pd-catalysed formation of benzene byproduct 88   XXII     of aryl catalysed halides       Scheme 3.9 Proposed mechanism for Pd-PEG-EG catalysed homocoupling of bromobenzene for formation of ... protodecarboxylation XXIII     of     Scheme 6.6 Proposed mechanism for formation of 3-NBP 208 Scheme 6.7 Proposed mechanism for formation of DNBP 209   XXIV           LIST OF JOURNAL PUBLICATIONS...

Ngày tải lên: 10/09/2015, 09:07