SACHARIDY (CUKRY) II.
|
|
- Lewis Fleming
- 5 years ago
- Views:
Transcription
1 SACARIDY (CUKRY) II. 1
2 Reakcie monosacharidov xidácie Alifatické aldehydy v miernych podmienkach ľahko oxidujú na karboxylové kyseliny, zatiaľ čo ketóny sú rezistentné. Slabo kyslé vodné roztoky halogénov transformujú aldózy na aldónové kyseliny. Ich izolácia je však problematická, lebo dehydratáciou okamžite cyklizujú na príslušné aldonolaktóny. Vo vodných roztokoch sa ustáli medzi laktónom a kyselinou rovnováha v závislosti od štruktúry a p. X 2, 2, p D-glukóza (X = Cl 2, Br 2, I 2 ) 87% D-glukonolaktón - 2 (Alkoholy a ketóny nepodliehajú oxidácii X 2!) Kyselina D-glukónová (Aldónová kyselina) Silné oxidačné činidlá (N 3 ) oxidujú okrem aldehydu aj primárne alkoholy za vzniku aldárových kyselín. Z D-glukózy tak vzniká kyselina D-glukárová, ktorá in situ dehydratáciou poskytne laktóny. N 3 1 C C C 2 2 D-glukóza Kyselina D-glukárová (Aldárová kyselina) 1,4-Laktón 6,3-Laktón 2 C 1 2
3 Reakcie monosacharidov xidácie Využitie Aldózy (ketózy ťažšie) poskytujú reakciou s Tollensovým činidlom príslušné aldónové kyseliny. xidantom je diamino-strieborný katión, ktorý sa redukuje na metalické striebro. Test všeobecne dokazuje prítomnosť voľných -C skupín oxidovateľných na príslušné karboxylové kyseliny. R [Ag(N 3 ) 2 ] + (R Me) + Ag 0 D-manóza (R=) Kyselina D-manónová "Strieborné zrkadlo" Tollensovo činidlo: kvalitatívny dôkaz redukujúcich cukrov Roztok CuS 4 (modrej skalice) v komplexe s vínanom (Fehling) resp. citrátom (Benedict) oxiduje alifatické aldehydy na príslušné aldónové kyseliny za vzniku červeno-hnedého precipitátu Cu 2. R D-galaktóza (R=) Cu 2+ vínan draselný (R Me) Kyselina D-galaktónová + Cu 2 Fehlingovo činidlo: klinický test diabetu - (ne)prítomnosť glukózy v moči 3
4 Reakcie monosacharidov xidácie Štiepenie diolov Reakcia vicinálnych diolov s kyselinou jodistou ( 5 I 6 ) alebo jej soľami poskytne cyklický esterový intermediát, ktorý sa štiepi za vzniku dvoch molekúl aldehydu. Tento typ oxidácie monosacharidov sa často využíva ako analyticky, tak aj synteticky. Napríklad z ochráneného D-manitolu sa oxidáciou s jodistanom sodným pripravuje bisacetonid D-glyceraldehydu ako užitočný chirálny medziprodukt. NaI 4 - Na + I + NaI acetón 2 S 4 NaI 4 Me/ 2 0 C 2 x D-manitol Bisacetonid D-manitolu Bisacetonid D-glyceraldehydu 4
5 Reakcie monosacharidov Redukcie Aldózy a ketózy sú hydridmi redukovateľné na príslušné alditoly za vzniku novej hydroxyskupiny. Zatiaľ čo aldóza poskytuje redukciou 1 produkt (glukóza glucitol), ketóza dáva diastereomérne alditoly (fruktóza glucitol + manitol). Dôvodom je diastereotopia karbonylovej skupiny ketóz. NaB 4 Et ( 2, Pd/C) NaB 4 Et NaB 4 Et D-glukóza (aldóza) D-glucitol (alditol) D-fruktóza (ketóza) D-manitol (alditol) Významným stereochemickým dôsledkom redukcie manózy na manitol je zmena symetrie produktu. Nakoľko D-manitol má oba konce reťazca identické (-C 2 ), vykazuje molekula C 2 -os symetrie. 5
6 Reakcie monosacharidov Redukcie furanose 6
7 Reakcie monosacharidov Redukcie 7
8 Reakcie monosacharidov Redukcie Alditoly ako sladidlá Redukciou niektorých cukrov sa dajú pripraviť achirálne alditoly, nakoľko majú rovinu symetrie. Xylóza poskytuje redukciou alkohol xylitol, ktorý napriek prítomnosti 3 stereogénnych centier neotáča rovinu polarizovaného svetla. Ide o tzv. mezo-zlúčeninu, ktorá je zrkadlovo symetrická. Xylitol je približne rovnako sladký ako sacharóza, pričom nesladká xylóza sa extrahuje v značných množstvách z rastlinného odpadu ako sú piliny alebo kukuričné šúľky. Xylitol sa používa ako relatívne lacné sladidlo, navyše nespôsobuje zubný kaz, nakoľko mliečne baktérie ho nie sú schopné metabolizovať na príslušné kyseliny. Cicavce však xylitol na rozdiel od baktérií čiastočne metabolizujú, preto môže slúžiť ako zdroj energie. Väčšie množstvá však majú na tráviaci systém laxatívny účinok. 8
9 Reakcie monosacharidov v bázickom prostredí Zriedené roztoky Aldózy (ale aj ketózy) podliehajú v zriedených bázických roztokoch epimerizačným prešmykom. D-glukóza v prítomnosti 0.035% Na poskytuje zmes D-fruktózy, D-manózy a pôvodnej D-glukózy. Interkonverzia D-glukóza D-manóza je epimerizáciou a kompletný prešmyk sa nazýva Lobry de Bruin-van Ekensteinova reakcia. Kľúčovým krokom je enolizácia D-glukózy na éndiol, ktorý následne ketonizuje 3 rôznymi spôsobmi na finálnu D-fruktózu, D-manózu a D-glukózu. D-glukóza (57%) 0.035% Na 35 C, 100 h éndiol D-glukózy D-fruktózy D-manózy Epimerizácia a aldózovo-ketózový prešmyk (Lobry de Bruin-van Ekensteinova reakcia) D-fruktóza (28%) D-manóza (3%) 9
10 Reakcie monosacharidov v bázickom prostredí Koncentrované roztoky Koncentrovanejšie bázické roztoky transformujú aldózy na príslušné 3-deoxyaldónové kyseliny. Prvým krokom je priama b-eliminácia vody z voľného monosacharidu za vzniku 1,2-dikarbonylovej zlúčeniny. Nasleduje adícia - nukleofilu a hydridový prešmyk poskytne finálnu aldónovú kyselinu. Nakoľko v bázickom prostredí sú hydroxylové skupiny monosacharidov čiastočne deprotonované, rýchlosť určujúcim (t. j. najpomalším) krokom celého mechanizmu je iniciálna b-eliminácia vody. Ako katalytická báza sa najčastejšie používa Ca() 2, nakoľko Ca 2+ ióny efektívne komplexujú enol. 1% Ca() C 2 D-allóza Kyselina 3-deoxyallónová 10
11 Reakcie monosacharidov v kyslom prostredí D-glukóza 2M 2 S C pomaly DEGRADÁCIA 2M 2 S C rýchlo polysacharid Kyslo-katalyzovaná dehydratácia (- 3 2 ) monosacharidov poskytuje 5-hydroxymetylfurfural (MF). ALDalebo KET- EXÓZA hydroxymetylfurán-2-karbaldehyd (5-MF) Výroba a využitie MF 11
12 Mechanizmus vzniku MF z D-fruktózy D-fruktopyranóza (1) ekvilibruje na D-fruktofuranózu (2), ktorá iniciálnou dehydratáciou poskytuje enol (3). Následnou dehydratáciou jeho oxo-formy vzniká a,b-nenasýtený aldehyd (4), ktorý podlieha finálnej dehydratácii za vzniku 5-hydroxymetylfurfuralu (MF) ako stabilného a konečného produktu. Nakoľko enolizácia je rýchlosť určujúci krok vzniku MF, D-fruktóza reaguje rýchlejšie ako D-glukóza enolizáci a 1. Tautomerizácia
13 Mechanizmus vzniku MF z D-glukózy Reaktivita D-glukózy (aldózy) je značne vyššia ako D-fruktózy (ketózy), čoho prejavom je oveľa menšie zastúpenie acyklickej glukózy v porovnaní s rovnovážnou koncentráciou otvorenej formy D-fruktózy. Avšak nakoľko D-glukóza tvorí stabilné cyklické štruktúry, jej enolizácia je pomalšia ako u D-fruktózy. Alternatívnym mechanizmom je iniciálna izomerizácia D-glukózy na D-fruktózu, ktorá sa už následne transformuje na finálny 5-hydroxymetylfurfural vyššie uvedenou kyslo-katalyzovanou transformáciou. D-glukóza Éndiol ydroxyketón D-fruktóza 13
14 Využitie 5-hydroxymetylfurfuralu (MF) 5-ydroxymetylfurfural (MF) je kľúčovým medziproduktom syntézy mnohých užitočných zlúčenín: - biopaliva 2,5-dimetylfuránu (DMF) ako alternatívy k (bio)etanolu, - fotosenzitizéru kyseliny levulínovej na fotodynamickú onkoterapiu, - monoméru FDA ako alternatívy kyseliny tereftalovej na prípravu plastov. 14
15 Kyslo-katalyzovaná hydrolýza celulózy Intra- a intermolekulové vodíkové väzby spôsobujú extrémnu stabilitu a nerozpustnosť celulózy. Výzvou je selektívna a zároveň efektívna chemodegradácia celulózy na využiteľné monosacharidy. Kyslá hydrolýza celulózy na monosacharidy je známa od roku 1819 (Braconnot), pričom charakter produktov závisí od typu a koncentrácie Brønstedovej kyseliny, rozpúšťadla, teploty a reakčného času. Zahrievanie celulózy v konc. roztoku 2 S 4 pri ~100 C počas 5-7 h poskytne >80% výťažok D-glukózy. 15
16 Kyslo-katalyzovaná hydrolýza celulózy Významnou nevýhodou štandardného technického prevedenia hydrolýzy celulózy koncentrovanou Brønstedovou kyselinou (napr. 2 S 4 ) je korózia aparatúry a generovanie značne kyslého odpadu. Riešením je použitie imobilizovaného heterogénneho kyslého katalyzátora, ktorý je navyše ľahko odstrániteľný z reakčnej zmesi po ukončení hydrolýzy - napr. vo forme magnetických nanočastíc. Katalyzátor pozostáva z polymérnej matrice na báze silánov obsahujúcich terminálne -S 3 skupiny. Kombináciou polyméru s nanočasticami Fe 3 4 sa získa tuhá magnetická kyselina s definovanou mezoporéznou mikroštruktúrou. Pripravený heterogénny katalyzátor je tepelne stabilný a recyklovateľný. (Lai et al.: ChemSusChem 2011, 4, 55) 16
17 Katalytické one-pot transformácie celulózy 17 17
18 Využitie lignocelulózy na výrobu chemikálií a palív 18
19 Reakcie monosacharidov Degradácie Ruff Ruffova degradácia využíva peroxid vodíka v prítomnosti železitanov na premenu vápenatých solí hexónových kyselín na pentózy. Tentatívne sa predpokladá vznik komplexu cukor/fe 3+ / (Ca 2+ ) 1/ Fe 3+ + C 2 D-Glukonát vápenatý (exóza) D-Arabinóza (Pentóza) tto Ruff ( ) Mechanisticky predstavuje Ruffova degradácia dvojnásobnú (jedno)elektrónovú oxidáciu. V prvom kroku je aldonát (1) oxidovaný na acyloxy radikál (2), ktorý po eliminácii C 2 a následnej oxidácii poskytne karbkatión (3). Ten je finálne atakovaný 2 za vzniku gem-diolu. 19
20 Reakcie monosacharidov Degradácie unsdiecker unsdieckerova degradácia zahŕňa bromáciu striebornej soli karboxylovej kyseliny s následnou termickou dekarboxyláciou za vzniku o uhlík kratšieho alkylhalidu. Ten sa finálnou reakciou s AgAc prevedie na maskovaný aldehyd, ktorý sa izoluje vo forme diesteru terminálneho acetálu. Ac - Ag + Ac Ac Ac Ac Br 2, CCl 4 80 C, 4 h Ac Br Ac Ac Ac Ac - C 2 Ac Br Ac Ac Ac Ac AgAc Ac Ac Ac Ac Ac Ac D-gluko (exóza) D-arabino (Pentóza) einz unsdiecker & Cläre unsdiecker ( ) ( ) University of Göttingen 20
21 Reakcie monosacharidov omologácie Kiliani-Fischer Kyanidový anión reprezentuje dostupnú formu nukleofilného uhlíka, ktorý reaguje s aldehydmi a ketónmi za vzniku kyánhydrínov. Tie obvykle nie sú izolované, ale priamo hydrolyzované na príslušné aldónové kyseliny. Z nich sa finálne aldózy dajú pripraviť totálnou redukciou s LiAl 4. CN C 2 D-Arabinóza (Pentóza) NaCN 2 p 9 + CN + / 2 + / 2 + C 2 Kyselina D-glukónová Kyselina D-manónová Kyánhydríny (exózy) 21
22 (BI)SYNTÉZA MNSACARIDV 22
23 Najdôležitejšia (bio)chemická reakcia na Zemi Fotosyntéza 6 C chlorofyl C nm ( = 2870 kj/mol) 23
24 Formose reaction Background The self-condensation of formaldehyde is a one-pot reaction resulting in a complex mixture of sugars. Usually, an alkaline environment (p~11) and the presence of catalytically active species are required. The formose reaction was previously considered as a prebiotic source for carbohydrates generation. owever, due to the fast degradation of sugars and the missing selectivity, this hypothesis is doubtful. Alexander Michailovič Butlerov ( ) 24
25 Formose reaction Mechanism Formaldehyde usually does not react with itself establishing a C C bond, so that the simplest sugar glycolaldehyde is formed slowly. owever, as soon as some condensation product is present, a cascade of reactions is initiated, ultimately leading to the formation of various straight/branched carbohydrates. Elongation of the carbohydrate backbone occurs via base-catalysed aldol condensation with C, accompanied by isomerisations. In alkaline medium retro-aldol reactions take place as well, whereupon both resulting fragments can act as initiators again, thus leading to an autocatalytic system. Due to their relative stability pentoses and hexoses are the main products. For prolonged reaction times however they decompose, recognisable by the yellowing / darkening of the reaction mixture. 25
26 ydrothermal formose reaction abitats with superheated water are available in submarine areas with volcanic activity and such hydrothermal vents with temperatures around 200 C at a pressure of 20 bar are present in oceans. In order to mimic such a demanding conditions, a continuous flow-reactor was designed and tested. Thus, a 0.5 M formaldehyde solution was heated to 200 C under a pressure of 100 bar. (It should be noted, however, that such a high concentration of C is not along with prebiotic conditions.) To vary the p and to probe for the potential catalysis of simple ions (Na, K, Ca) salts were added. Contrary to the formose reaction at ambient temperatures, where hexoses are the main products, here the shorter carbohydrates (tetroses and pentoses) are preferentially formed. Despite the high stability that is in principle expected for hexoses, their amount is insignificant at 200 C. Thus, these results do not show the formose reaction as a player in the prebiotic formation of carbohydrates. ydrothermal vent (Black smoker) (D. Kopetzki et al.: New J. Chem., 2011, 35, 1787) 26
27 Biosyntéza kyseliny L-askorbovej Esenciálny vitamín Má antioxidačné vlastnosti D-enantiomér je neaktívny 27
28 Biosyntéza kyseliny L-askorbovej [] 28
CHEMISTRY MIDTERM # 2 November 02, The total number of points in this midterm is 100. The total exam time is 120 min (2 h). Good luck!
CEMISTRY 314-01 MIDTERM # 2 November 02, 2009 Name... The total number of points in this midterm is 100. The total exam time is 120 min (2 h). Good luck! 1. (8 pts) Mark as true (T) or false (F) the following
More informationChemistry 3720, Spring 2004 Exam 3 Name:
Chemistry 3720, Spring 2004 Exam 3 Name: This exam is worth 100 points out of a total of 600 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam and you may use the spectroscopy data
More informationChem 263 Nov 19, Cl 2
Chem 263 Nov 19, 2013 eactions of Enolates: X X alogenation X C 2 Alkylation C Aldol eaction X C Acylation Example: halogenation LDA 2 Chloroacetone is used in tear gas. chloroacetone In this reaction,
More informationLoudon Chapter 24 Review: Carbohydrates CHEM 3331, Jacquie Richardson, Fall Page 1
CEM 3331, Jacquie Richardson, Fall 2010 - Page 1 This chapter is about carbohydrates molecules with the general formula of C n ( 2 ) n, or in other words C n 2n n. This is a very common formula for sugars
More informationORGANIC - BRUICE 8E CH THE ORGANIC CHEMISTRY OF CARBOHYDRATES
!! www.clutchprep.com CONCEPT: INTRODUCTION TO CARBOHYDRATE MONOSACCHARIDES Sugars or saccharides are also referred to as carbo-hydrates, implying that carbon has been combined with Monosaccharides are
More informationORGANIC - CLUTCH CH CARBOHYDRATES.
!! www.clutchprep.com CONCEPT: INTRODUCTION TO CARBOHYDRATE MONOSACCHARIDES Sugars or saccharides are also referred to as carbo-hydrates, implying that carbon has been combined with Monosaccharides are
More informationAldehydes and Ketones : Aldol Reactions
Aldehydes and Ketones : Aldol Reactions The Acidity of the a Hydrogens of Carbonyl Compounds: Enolate Anions Hydrogens on carbons a to carbonyls are unusually acidic The resulting anion is stabilized by
More informationAldehydes and Ketones Reactions. Dr. Sapna Gupta
Aldehydes and Ketones Reactions Dr. Sapna Gupta Reactions of Aldehydes and Ketones Nucleophilic Addition A strong nucleophile attacks the carbonyl carbon, forming an alkoxide ion that is then protonated.
More informationSyntetické štúdie prípravy fluórovaných TEMPO analógov
SLOVENSKÁ TECHNICKÁ UNIVERZITA V BRATISLAVE FAKULTA CHEMICKEJ A POTRAVINÁRSKEJ TECHNOLÓGIE Syntetické štúdie prípravy fluórovaných TEMPO analógov BAKALÁRSKA PRÁCA FCHPT-13569-44025 Bratislava, 2015 Martin
More informationHomework Problem Set 11 Iverson CH320N Due Friday, May 5
omework Problem Set 11 Iverson 320 Due Friday, May 5 AME (Print): SIGATURE: hemistry 320 Dr. Brent Iverson Problem Set 11 April 28, 2017 Please print the first three letters of your last name in the three
More informationMARK SCHEME for the October/November 2014 series 9701 CHEMISTRY
CAMBRIDGE INTERNATINAL EXAMINATINS Cambridge International Advanced Level MARK SCEME for the ctober/november 204 series 970 CEMISTRY 970/43 Paper 4 (A2 Structured Questions), maximum raw mark 00 This mark
More informationORGANIC - BROWN 8E CH CARBOHYDRATES.
!! www.clutchprep.com CONCEPT: INTRODUCTION TO CARBOHYDRATE MONOSACCHARIDES Sugars or saccharides are also referred to as carbo-hydrates, implying that carbon has been combined with Monosaccharides are
More informationH H H OH OH H OH H O 1 CH 2 OH
Name 215 F07-Exam No. 3 Page 2 I. (29 points) Streptomycetes are soil-dwelling, filamentous, Gram-positive saprophytic bacteria. They are responsible for over 50% of the known microbial metabolites, including
More informationCHEM 203. Final Exam December 16, This a closed-notes, closed-book exam. You may use your set of molecular models
CEM 203 Final Exam December 16, 2014 Your name: This a closed-notes, closed-book exam You may use your set of molecular models This test consists of 10 pages Time: 2h 30 min 1. / 20 2. / 20 3. / 30 4.
More informationTHE UNIVERSITY OF CALGARY FACULTY OF SCIENCE FINAL EXAMINATION CHEMISTRY 350
Page 1 of 16 TE UNIVERSITY F CALGARY FACULTY F SCIENCE FINAL EXAMINATIN CEMISTRY 350 April, 1997 Time: 3 ours PLEASE WRITE YUR NAME, STUDENT I.D. NUMBER AND SECTIN NUMBER (01 for MWF lectures and 02 for
More informationUCSC, Binder. CHEM 8B Organic Chemistry II FINAL EXAM (300 points)
UCSC, Binder Name CEM 8B rganic Chemistry II FINAL EXAM (300 points) In each of the following problems, use your knowledge of organic chemistry conventions to answer the questions in the proper manner.
More informationCHEMISTRY Topic #8: Oxidation and Reduction Reactions Fall 2018 Dr. Susan Findlay
CEMISTRY 2600 Topic #8: xidation and Reduction Reactions Fall 2018 Dr. Susan Findlay xidation States of Carbon Carbon can have any oxidation state from -4 (C 4 ) to +4 (C 2 ). As a general rule, increasing
More informationO H HO H. !-D-galactopyranose
ame Key W06-Exam o. Page I. ( points) A disaccharide is cleaved by a β-glycosidase, an enzyme that specifically hydrolyzes a β- glycosidic linkage. When the disaccharide is treated with excess dimethyl
More informationChemistry 110. Bettelheim, Brown, Campbell & Farrell. Ninth Edition
hemistry 110 Bettelheim, Brown, ampbell & Farrell Ninth Edition Introduction to General, rganic and Biochemistry hapter 17 Aldehydes & Ketones hemistry of the arbonyl Group Aldehydes & Ketones The functional
More informationTest Date: 30th September, 2018 (Sunday) Venue: Lajpat Rai Bhawan, Sector 15-B, Chandigarh
Test Date: 0th September, 2018 (Sunday) Venue: Lajpat Rai Bhawan, Sector 15-B, handigarh Syllabus Physics hemistry Biology 1. Electrostatics 2. apacitors. urrent Electricity 4. Magnetic effects 5. Magnetism
More informationORGANIC CHEMISTRY II 3. CARBONYL COMPOUNDS PREVIOUS EAMCET BITS.
1 RGANIC EMISTRY II. CARBNYL CMPUNDS PREVIUS EAMCET BITS Cl Cl 1. What are the X and Y in the following reaction sequence : X Y (009 E) 1) 5, ), ), CCl 4) 5Cl, CCl Reaction. Cl HCl X Cl CCl. HCl Y. The
More informationTopic 9. Aldehydes & Ketones
Chemistry 2213a Fall 2012 Western University Topic 9. Aldehydes & Ketones A. Structure and Nomenclature The carbonyl group is present in aldehydes and ketones and is the most important group in bio-organic
More informationChem 312 SS05 Page 1 of 6 Kantorowski. 17 August 2005 Name:
Chem 32 SS05 Page of 6 Kantorowski Exam III Key 7 August 2005 Name: This exam contains 5 pages of questions confirm this once you begin. You will have 50 minutes An abbreviated Periodic Table can be found
More informationA. B. C. D. 2. Which compound does not give a stable Grignard reagent when reacting with Mg metal?
Practice Test, Chemistry 2220 Final Exam 1. Which structure has the MST signals for its proton NMR? 2. Which compound does not give a stable Grignard reagent when reacting with Mg metal? 3. Which of these
More informationGrade:12 Chemistry Olympiad Qualifier Set:2
Grade:12 Chemistry Olympiad Qualifier Set:2 ----------------------------------------------------------------------------------------------- Max Marks: 60 Test ID: 13112 Time Allotted : 40 Mins -----------------------------------------------------------------------------------------------
More informationCHEMISTRY 332 FINAL EXAM. December 14, I. (18 points) II. (48 points) III. (50 points) IV. (40 points) V. (26 points) VI.
Seat No. Name (please print and circle your last name) CEMISTRY 332 FINAL EXAM December 14, 2005 I. (18 points) II. (48 points) III. (50 points) IV. (40 points) V. (26 points) VI. (18 points) TTAL (200
More informationChem 30A Winter Mon March 21st
Last Name First Name MI Student ID Number: Total Score / 200 Chem 30A Winter 2005 FINAL (180 Min) Mon March 21st Course Grade ***DO NOT OPEN THIS EXAM UNTIL INSTRUCTED TO DO SO*** ONLY ANSWERS WRITTEN
More informationLecture Notes Chem 51C S. King Chapter 24 Carbonyl Condensation Reactions
Lecture Notes Chem 51C S. King Chapter 24 Carbonyl Condensation Reactions I. Reaction of Enols & Enolates with ther Carbonyls Enols and enolates are electron rich nucleophiles that react with a number
More informationBackground Information
ackground nformation ntroduction to Condensation eactions Condensation reactions occur between the α-carbon of one carbonyl-containing functional group and the carbonyl carbon of a second carbonyl-containing
More informationNucleophilic Heterocyclic Carbene Catalysis. Nathan Werner Denmark Group Meeting September 22 th, 2009
Nucleophilic Heterocyclic Carbene Catalysis Nathan Werner Denmark Group Meeting September 22 th, 2009 Thiamine Thiamine Vitamin B 1 The first water-soluble vitamin described Is naturally synthesized by
More informationChem 215 F11 Notes Dr. Masato Koreeda - Page 1 of 18. Date: November 9, 2011
Chem F Notes Dr. Masato Koreeda - Page of 8. Date: November 9, 0 Chapters.8; -,,, and 7: Carbohydrates Part I Carbohydrate nomenclature: http://www.chem.qmul.ac.uk/iupac/carb/ Carbohydrates: Polyhydroxylated
More informationAnalytická chémia I. Analytické meranie. Princípy analytických meraní 2/13/2018
Analytická chémia I 2017/2018 prof. Ing. Ivan Špánik, DrSc. Ústav Analytickej chémie miestnosťč. 490, 566, 379 Klapka 283 e-mail: ivan.spanik@stuba.sk Analytické meranie Signál Dekódovanie Vzorka Informácia
More informationAnother Equilibrium: Reaction At The α-position
Another Equilibrium: Reaction At The α-position D 3 + D 3 C CD 3 2 C 2 the keto form the enol form chanism: + C 2 C 2 C 2 D D 2 D 2 repeat 5 times D 3 C CD 3 alogenation At The α-position Br 2, 2 C 2 Br
More informationExam III 17 August 2005 Name:
Chem 312 SS05 Page 1 of 6 Kantorowski Exam III 17 August 2005 Name: This exam contains 5 pages of questions confirm this once you begin. You will have 50 minutes An abbreviated Periodic Table can be found
More informationChapter 3: Elements and Compounds. 3.1 Elements
Chapter 3: Elements and Compounds 3.1 Elements An element is a fundamental substance that cannot be broken down by chemical or physical methods to simpler substances. The 118 known elements are nature
More informationFaculty of Science Mid-Term Examination II. Chem 222/234 Introductory Organic Chemistry I
Student Name: Student ID #: Faculty of Science Mid-Term Examination II Chem 222/234 Introductory rganic Chemistry I Examiner: Professor James L. Gleason Tuesday, November 10, 2009 Associate Examiner: Professor
More informationChapter 20: Aldehydes and Ketones
Chapter 20: Aldehydes and Ketones [Chapter 20 Sections: 20.1-20.7, 20.9-10.10, 20.13] 1. Nomenclature of Aldehydes and Ketones ' ketone aldehyde f both aldehydes and ketones, the parent chain is the longest
More informationHomework 5 Organic Chemistry MCAT Review Summer 2012 Brent Iverson
omework 5 rganic Chemistry MCAT Review Summer 2012 ent Iverson 1 1. For the following reactions, draw the predominant product or products. When a new chiral center is created, mark it with an asterisk
More informationWhat is in Common for the Following Reactions, and How Do They Work?
What is in Common for the Following Reactions, and ow Do They Work? You should eventually be able to draw the mechanism for these (and other) reactions 13 Key Intermediate 1 Br-Br Na Br 2 C 3 -I Me NaMe
More informationDetermination of Reducing Sugar Content: Clinitest, Benedict s Solution and the Rebelein Titration
Determination of Reducing Sugar Content: Clinitest, Benedict s Solution and the Rebelein Titration Chemical Concepts and Techniques: The most important sugars present in wine and fruit juice are the hexoses
More informationCEM 252, Fall 2018 Midterm Exam 3, Version A Wednesday, 14 November, 2018, 6:00 PM Room 138, Chemistry Name (print) Signature Student # Key
CEM 252, Fall 2018 Midterm Exam 3, Version A Wednesday, 14 November, 2018, 6:00 PM Room 138, Chemistry Name (print) Signature Student # Key Version Section Number (-2 pts if you don t know this) A Feed
More informationSuggested solutions for Chapter 28
s for Chapter 28 28 PBLEM 1 ow would you make these four compounds? Give your disconnections, explain why you chose them and then give reagents for the. 2 2 Me S Exercises in basic one- group C X disconnections.
More informationAnswers To Chapter 7 Problems.
Answers To Chapter Problems.. Most of the Chapter problems appear as end-of-chapter problems in later chapters.. The first reaction is an ene reaction. When light shines on in the presence of light and
More informationCEM 252, Fall 2018 Midterm Exam 3, Version B Wednesday, 14 November, 2018, 6:00 PM Room 138, Chemistry
CEM 252, Fall 2018 Midterm Exam 3, Version B Wednesday, 14 November, 2018, 6:00 PM Room 138, Chemistry Name (print) KEY VERSIN B Signature Student # Section Number (-2 pts if you don t know this) Feed
More informationI N V E S T I C E D O R O Z V O J E V Z D Ě L Á V Á N Í CARBONYL COMPOUNDS
= substances containing the carbonyl group Aldehydes have the C=O group at the end of the chain, the aldehydic group is then... Naming of aldehydes: In the systematic name there is a suffix after the stem
More informationChemistry 52 Final Exam. Name: 9 March This exam has six questions, two cover pages, seven exam pages, and two scratch pages.
Chemistry 52 Final Exam Name: 9 March 2002 This exam has six questions, two cover pages, seven exam pages, and two scratch pages. Please check before beginning to make sure no questions or pages are missing.
More informationCHEM 203. Final Exam December 15, 2010 ANSWERS. This a closed-notes, closed-book exam. You may use your set of molecular models
CEM 203 Final Exam December 15, 2010 Your name: ANSWERS This a closed-notes, closed-book exam You may use your set of molecular models This test contains 15 pages Time: 2h 30 min 1. / 16 2. / 15 3. / 24
More informationChem 221b. Problem Set 9, Chapter 23. Carbohydrates. Due: Monday, April 18, Last year's PS9 was so good, here it is again.
Chem 221b Problem Set 9, Chapter 23 Carbohydrates Due: Monday, April 18, 2005 Last year's PS9 was so good, here it is again. The graphic on the left was conceived by M. A. Rosanoff in 1906 as a means of
More informationPractice Packet Unit 6: Moles & Stoichiometry
Regents Chemistry: Mr. Palermo Practice Packet Unit 6: Moles & Stoichiometry 1 LESSON 1: Moles and Molar Mass 1. Put an M if the substance is molecular/covalent, an I if ionic under the formula listed.
More informationNew bond. ph 4.0. Fischer esterification. New bond 2 O * New bond. New bond H 2N. New C-C bond. New C-C bond. New C-C bond. O Cl.
Iverson C 0N KRE Table: For use in synthesis problems, count carbons in products and starting materials then identify location(s) of new s, especially C-C or C=C s. With that information, use the following
More informationSupporting Information
Supporting Information Catalytic Reductive Aminolysis of Reducing Sugars: Elucidation of Reaction Mechanism *, a c Laboratory for Chemical Technology, Technologiepark 914, 9052 Gent (Belgium) S1 Table
More informationPeriodic Properties of the Elements. Chapter 7
Periodic Properties of the Elements Chapter 7 The Sizes of Atoms The bond distance: d The covalent radius of the atom Non-bonding atomic radius Atomic size varies consistently through the periodic table.
More informationALDEHYDE, KETONES,& CARBOXYLIC ACID. a) 2-hydroxy-2-methylpropanenitrile
ALDEHYDE, KETNES,& CARBXYLIC ACID 1) C H 3 CH dil.h 2 S 4 HgS 4 A HCN H 2 /Ni B The IUPAC name of B is 2-hydroxy-2-methylpropanenitrile b) 2-hydroxy-2-methylpropanoic acid 2-hydroxypropanoic acid d) 1-amino-2-methylpropanol-2
More informationEXAMINATION 1 Chemistry 3B. Making up an I Grade (If you are, please indicate the semester during which you took previous Chem 3B:
1 EXAMINATIN 1 Chemistry 3B Name: Print first name before second! Use capital letters! SID #: Peter Vollhardt February 23, 2006 Please provide the following information if applicable. Making up an I Grade
More information11/14/2016. NaBH 4. Superimposable on mirror image. (achiral) D-ribose. NaBH 4 NaBH 4. Not superimposable on mirror image.
There are multiple ways to relate the structures of ketoses to aldoses. Reduction of a ketose with NaB 4 forms a new stereocenter and thus forms a mixture of two alditols. An aldopentose forms a chiral
More informationChemistry 39. Final Exam
Chemistry 39 Final Exam Tuesday, May 7, 2005 ame (printed) 11:10 am S.S. # Signature Please show your picture I.D. to a proctor when you hand in your exam. TTAL 1 There are 25 questions on this exam. Check
More information(CHE 325) Organic Chemistry II Spring 2011 EXAM #4
(CE 325) rganic Chemistry II Spring 2011 EXAM #4 ame: KEY ID#: Check your exam to be sure it is complete. There are eight questions in this exam. It is worth 100 points. To receive full credit for your
More informationCHE 232 Organic Chemistry II Exam 4 Name: KEY
CE 232 rganic Chemistry II Exam 4 ame: KEY Student number: Before you begin this exam: First: You are allowed to have a simple model set at your seat. Please put away all other materials. Second: Place
More informationName Date Period Ionic Bonding Puzzle Activity
Name Date Period Ionic Bonding Puzzle Activity Introduction When metals and non-metals chemically react, the atoms will tend to form ions or charged atoms. Ions form because electrons are either gained
More informationImportance of Carbohydrates
Chapter 25 Importance of Carbohydrates Distributed widely in nature Key intermediates of metabolism (sugars) Structural components of plants (cellulose) Central to materials of industrial products: paper,
More informationLecture Notes Chem 51C S. King. Chapter 20 Introduction to Carbonyl Chemistry; Organometallic Reagents; Oxidation & Reduction
Lecture Notes Chem 51C S. King Chapter 20 Introduction to Carbonyl Chemistry; rganometallic Reagents; xidation & Reduction I. The Reactivity of Carbonyl Compounds The carbonyl group is an extremely important
More informationKapitola S5. Skrutkovica na rotačnej ploche
Kapitola S5 Skrutkovica na rotačnej ploche Nech je rotačná plocha určená osou rotácie o a meridiánom m. Skrutkový pohyb je pohyb zložený z rovnomerného rotačného pohybu okolo osi o a z rovnomerného translačného
More informationCHEM J-14 June 2014
CHEM1101 2014-J-14 June 2014 An electrochemical cell consists of an Fe 2+ /Fe half cell with unknown [Fe 2+ ] and a Sn 2+ /Sn half-cell with [Sn 2+ ] = 1.10 M. The electromotive force (electrical potential)
More informationCarbonyl groups react via nucleophilic addition, with the mechanism being represented as follows:
Aldehydes and Ketones Introduction Aldehydes and ketones are two similar homologous groups both having the carbonyl group: The Carbon on the carbonyl group is slightly positive wince the Oxygen is pulling
More informationCHE 113 MIDTERM EXAMINATION October 25, 2012
CHE 113 MIDTERM EXAMINATION October 25, 2012 University of Kentucky Department of Chemistry READ THESE DIRECTIONS CAREFULLY BEFORE STARTING THE EXAMINATION! It is extremely important that you fill in the
More information(please print and circle your last name) CHEMISTRY 332 FINAL EXAM. December 11, 2006
Seat No. Name (please print and circle your last name) CEMISTRY 332 FINAL EXAM December 11, 2006 I. (18 points) II. III. IV. (48 points) (50 points) (40 points) V. (26 points) VI. (18 points) TTAL (200
More informationI. Write Structures for the compounds named below: (12 points) H 2 N NH 2. Acetone Hydrazine Cyclohexane carbaldehyde H 3 C
I. Write Structures for the compounds named below: (12 points) 3 2 N N 2 Acetone ydrazine yclohexane carbaldehyde N P( 6 5 ) 3 3 An ethyl ylide of Any imine 3-xo-6-phenylhexanal triphenylphosphine II.
More informationChapter 24 Carbohydrates
hapter arbohydrates Review of oncepts Fill in the blanks below. To verify that your answers are correct, look in your textbook at the end of hapter. Each of the sentences below appears verbatim in the
More informationChemistry 39. Exam 3
Chemistry 39 Exam 3 Wednesday, April 0, 005 Name (printed) 6:30-7:45 p.m. S.S. # Signature Please show your picture I.D. to a proctor when you hand in your exam. TTAL 1 There are 5 questions on this exam.
More informationTHE UNIVERSITY OF CALGARY FACULTY OF SCIENCE FINAL EXAMINATION CHEMISTRY 351 READ ALL THE INSTRUCTIONS CAREFULLY
TE UNIVERSITY F CALGARY FACULTY F SCIENCE FINAL EXAMINATIN CEMISTRY 351 DECEMBER 22nd 1999 Time: 3 ours READ ALL TE INSTRUCTINS CAREFULLY PLEASE WRITE YUR NAME, STUDENT I.D. NUMBER N BT YUR EXAM ANSWER
More informationChemistry 121(V84) Winter 2016
Chemistry 121(V84) Winter 2016 Introduction to Organic Chemistry and Biochemistry Instructor Dr. Upali Siriwardane (Ph.D. Ohio State) E-mail: upali@latech.edu Office: 311 Carson Taylor Hall ; Phone: 318-257-4941;
More informationSAMPLE PAPER-1 Q 1. Q 2. Q 3. Write IUPAC name of: C 6H 5 NHCOCH 3 1. Q 4. What is Kraft temperature? 1
Q. Q. SAMPLE PAPER- Class-XII Sub-Chemistry Time : hrs. M.M.70 Instructions:-. All Questions are compulsory. Question No to 8 are very short answer questions carrying mark each.. Question No 9 to 8 are
More informationChem 232. Problem Set 4. Table. Substrate Types and the Choice of S N 1 of S N 2
Chem 232 D. J. Wardrop wardropd@uic.edu Problem et 4 Does the nucleophilic substitution of substrate X proceed via an N 2 or N 1 mechanism? is a perennial question in rganic Chemistry. Use the table below
More informationCHEM 203. Final Exam December 18, This a closed-notes, closed-book exam. You may use your set of molecular models
CEM 203 Final Exam December 18, 2013 Your name: This a closed-notes, closed-book exam You may use your set of molecular models This test consists of 10 pages Time: 2h 30 min 1. / 20 2. / 20 3. / 30 4.
More informationCHEM 234, Spring 2015 PRINTED FIRST NAME. Final Exam ASU ID or Posting ID. Ian R. Gould PRINTED LAST NAME
CEM 234, Spring 2015 PRINTED FIRST NAME PRINTED LAST NAME Final Exam ASU ID or Posting ID Ian R. Gould Person on your LEFT (or Aisle) Person on your RIGT (or Aisle) 1 /12 2 /20 3 /25 4 /12 5 /20 6 /64
More informationMARK SCHEME for the October/November 2015 series 9701 CHEMISTRY
CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International Advanced Level MARK SCHEME for the October/November 05 series 970 CHEMISTRY 970/43 Paper 4 (A Structured Questions), maximum raw mark 00 This
More informationLife is a chemical process
CHEMISTRY FOR LIFE WHY STUDY CHEMISTRY? Chemistry is the ultimate (basic) cause of all physiological processes Interactions of atoms produce chemical changes Chemical reactions involve a transfer of energy
More informationIONIC CHARGES. Chemistry 51 Review
IONIC CHARGES The ionic charge of an ion is dependent on the number of electrons lost or gained to attain a noble gas configuration. For most main group elements, the ionic charges can be determined from
More information3) Between aldehyde and ketones which one is confirmed using Tollen s reagent.
UNIT ALDEHYDES KETONES AND CARBOXYLIC ACIDS ) What are aldehydes? Aldehydes are the organic compounds containing carbonyl group,linked with one hydrogen and one alkyl /aryl group. ) What are carboxylic
More informationThe Carbohydrates [C(H 2 O)] n. Emil Hermann Fischer ( )
The Carbohydrates [C(H 2 )] n Emil Hermann Fischer (1852-1919) The Fischer-Rosanoff Convention C C C H H C 2 - H H C 3 - H H C 4 - H H C 5 - CH 2 Fischer Projections CH 2 C 6 -CH 2 Rosanoff Modification
More informationAldehydes and Ketones
9 Aldehydes and Ketones hapter Summary The carbonyl group, =, is present in both aldehydes (=) and ketones ( 2 =). The IUPA ending for naming aldehydes is -al, and numbering begins with the carbonyl carbon.
More informationChemistry Questions ans Answers BASED ON HIGH ORDER THINKING SKILL (HOTS) UNIT- 12 ALDEHYDES, KETONES AND CARBXYLIC ACID
Chemistry Questions ans Answers BASED N IG RDER TINKING SKILL (TS) UNIT- 12 ALDEYDES, KETNES AND CARBXYLIC ACID 1 MARK QUESTINS Q. 1. Name the reaction and the reagent used for the conversion of acid chlorides
More information12. Aldehydes & Ketones (text )
2009, Department of Chemistry, The University of Western ntario 12.1 12. Aldehydes & Ketones (text 13.1 13.11) A. Structure and Nomenclature The carbonyl group is present in aldehydes and ketones and is
More informationThe Final Learning Experience
Chemistry 212 Fall Semester 1996 The Final Learning Experience University of Missouri Columbia, Prof. Rainer Glaser Monday, December 9, 1996, 103 Schlundt all, 12:40-2:30 Your Name: Max. Question 1 (Sugars)
More informationEXAMINATION 2 Chemistry 3A
1 EXAMINATIN 2 Chemistry 3A Name: KEY Print first name before second! Use capital letters! SID #: Peter Vollhardt April 11, 2017 GSI (if you are taking Chem 3AL): Please provide the following information
More informationCSUS Department of Chemistry Experiment 2 Chem. 1A EXPERIMENT 2: HYDRATE PRE-LABORATORY ASSIGNMENT
Name: Lab Section: EXPERIMENT 2: HYDRATE PRE-LABORATORY ASSIGNMENT 1. A student obtains the following data: Mass of test tube: Mass of test tube and hydrate: Mass of test tube and anhydrous residue after
More informationPRACTICAL NUMBER 1 TESTS FOR METAL IONS IN SOLUTION
PRACTICAL NUMBER 1 TESTS FOR METAL IONS IN SOLUTION INTRODUCTION Most common metals have insoluble hydroxides. They can be precipitated from solution by the addition of either ammonia solution (often referred
More informationH CH 2 -OH (4) H b. (5) H H. (6) a. b.
ame Key 15 F010-Exam o. Page I. (15 points) For each of the following pairs of compounds, predict which compound is more acidic. Compare the two underlined s for each pair and circle the compound that
More informationSECTION 12. «POT-POURRI» in Organic Synthesis (2018)
SECTIN 12 «PT-PURRI» in rganic Synthesis (2018) 1 Total Synthesis of Erythromycin A via a Spiroketal ERYTRMYCIN A DESLNGCAMPS et al. Can. J. Chem. 1985, 63, 2810-2820. 2 Tetrahydropyran Derivative as Starting
More information3 A (aq) + 2 D (aq) + 5 C (s) <==> 3 B (aq) + 4 E (aq) + 2 G (ppt)
AP Chemistry Test (Chapter 13) Multiple Choice (30%) 1) Which one best describes the K C for this reaction? 3 A (aq) + 2 D (aq) + 5 C (s) 3 B (aq) + 4 E (aq) + 2 G (ppt) A) K c = [A] 3 [D] 2 B) K
More informationMassachusetts Institute of Technology Organic Chemistry Problem Set 1. Functional Group Transformations Study Guide
Massachusetts Institute of Technology rganic Chemistry 5.511 Problem Set 1 September, 2007 Prof. Rick L. Danheiser Functional Group Transformations Study Guide The purpose of this three-part study guide
More informationMark Scheme Page 1 of 8 Unit ode 2814 Session Jan Year 2004 Qu. Expected answers: Marks: 1 (a) (i) (relative) molecular mass / M r (ii) right / highest m /e / highest mass / second highest mass etc AW
More informationEnols and Enolates. A type of reaction with carbonyl compounds is an α-substitution (an electrophile adds to the α carbon of a carbonyl)
Enols and Enolates A type of reaction with carbonyl compounds is an α-substitution (an electrophile adds to the α carbon of a carbonyl) E+ E In the preceding chapters, we primarily studied nucleophiles
More informationPractice Problems December 4, 2000
Practice Problems December, 000 ) Propose sequences of reactions that could accomplish each of the following transformations. Starting from N a) C Starting from Starting from c) ) Propose detailed, stepwise
More informationScore: Homework Problem Set 9 Iverson CH320N Due Monday, April 17. NAME (Print): Chemistry 320N Dr. Brent Iverson 9th Homework April 10, 2017
omework Problem Set 9 Iverson C0N Due Monday, April 7 NAME (Print): SIGNATURE: Chemistry 0N Dr. ent Iverson 9th omework April 0, 07 Please print the first three letters of your last name in the three boxes
More informationChapter 4 Chemical Formulas, Reactions, Redox and Solutions
Terms to Know: Solubility Solute Solvent Solution Chapter 4 the amount of substance that dissolves in a given volume of solvent at a given temperature. a substance dissolved in a liquid to form a solution
More informationCHEM J-14 June 2014
CHEM1101 2014-J-14 June 2014 An electrochemical cell consists of an Fe 2+ /Fe half cell with unknown [Fe 2+ ] and a Sn 2+ /Sn half-cell with [Sn 2+ ] = 1.10 M. The electromotive force (electrical potential)
More informationFirst Year Organic Chemistry THE CHEMISTRY OF THE CARBONYL GROUP: CORE CARBONYL CHEMISTRY
First Year rganic Chemistry TE CEMISTY F TE CABNYL GUP: CE CABNYL CEMISTY Professor Tim Donohoe 8 lectures, T, weeks 1-4, 2015 Wednesdays at 9am; Fridays at 10am (Dyson Perrins) andout A You will be able
More informationCHEMISTRY. ion is : 62. Which of the following salts is the most basic in aqueous solution?
JEE MAIN-018 CHEMISTRY This section contains 0 multiple choice questions. Each question has choices, (), () and for its answer, out of which Only One is correct. 61. Total number of lone pair of electrons
More informationChem 101 Review. Fall 2012
Chem 101 Review Fall 2012 Elements, Atoms, Ions Elements in nature symbols Constant composition chemical formula Dalton s atomic theory Atomic structure what makes up the atom ions isotopes Periodic table
More information