However, she was lazy and thus punished by being covered with pitch. In the cartoon, however, this is not pitch but polydopamine - something useful and valuable. Sometimes also lazy persons have good luck! More information can be found in the Minieview by J. The Cover Feature shows examples of small molecules that unfold G-quadruplex G4 nucleic acid structures. Hundreds of ligands bind G4 with high specificity and affinity, an adventure through the universe of these chemotypes discover molecules that can do more than simply associate with G4 in a host-guest fashion.
Small molecules can induce G4 conformational switching, selective covalent modification, and even allow the stimuli-responsive control of these fascinating architectures. The Cover Feature nucleic acid cartoons were kindly provided by S. Haldar and A. This addition requires about three and one-third hours Note 3. The mixture is allowed to stand overnight and is then poured upon 1 kg. The mixture is extracted with three cc.
The material that remains in the flask is fractionally distilled twice under diminished pressure. It weighs g. About 50 g. Since it is impossible to read that part of the thermometer scale which extends into the reaction flask, a thermometer should be used which when in position has the zero point above the stopper of the flask.
A gas trap of the type shown in Fig. Another gas trap is shown in Org. I, , After about two-thirds of the mixture has been added the rate of addition may be increased somewhat. The time required for the addition depends on the efficiency of the cooling and stirring; the stirring must be vigorous. With one-half of these amounts in a cc. From the first fractionation a fraction boiling over a 20 range is taken as crude ketone; e.
Much trouble is caused by the tendency of the ketone to become superheated. Acetyl chloride gives a better yield and less high-boiling residue than acetic anhydride.
This procedure has also been used successfully in the acetylation of cumene and tert. At the low temperatures employed there is very little decomposition, as is shown by the small amount of high-boiling residue. Discussion Aceto-p-cymene can be prepared by the action of acetyl chloride on p-cymene in the presence of anhydrous aluminum chloride1 or ferric chloride. Lacourt, Bull. Meissel, Ber. Appendix Chemical Abstracts Nomenclature Collective Index Number ; Registry Number Acetophenone, 5-isopropylmethylcalcium chloride hydrogen chloride, hydrochloric acid ether acetic anhydride acetyl chloride aluminum chloride carbon disulfide ferric chloride cymene, p-cymene cumene Aceto-p-cymene tert.
Levene and A. Checked by Frank C. Whitmore and J. Pauline Hollingshead. Procedure In a 3-l. Liebig condenser is placed g. The solution is cooled to below 50 Note 1 , g. Then g. At the end of the operation the solution is cooled to 0 in an ice-salt bath. The potassium bromide which settles is filtered on a cooled suction filter, and the filtrate is fractionated.
It is necessary to cool the mixture below 50 to prevent loss of the volatile ethyl formate. Technical ethyl formate was purified by washing with 3 per cent sodium carbonate solution, then with cold water, drying over anhydrous sodium sulfate, filtering, and fractionating. Compare p. It is very important that all the materials used in the synthesis of acetol be anhydrous, as otherwise condensation products are formed.
If commercial potassium formate is used it should be dried under reduced pressure at One and one-half to two moles should be used per mole of the bromo compound. Acetol polymerizes very readily on standing but remains unchanged when dissolved in an equal volume of methyl alcohol.
Discussion Acetol has usually been prepared by the reaction between bromoacetone and sodium or potassium formate or acetate, followed by hydrolysis of the ester with methyl alcohol. Nef, Ann. Urion, Ann. Holmes, Brit. Carbide and Carbon Chemicals Corporation, U. Pastureau, Bull. Appendix Chemical Abstracts Nomenclature Collective Index Number ; Registry Number sodium or potassium formate Baeyer and Villiger's acetone-peroxide reagent alcohol Acetol methyl alcohol glycerol sodium carbonate sodium sulfate acetone potassium hydroxide potassium bromide ethyl formate Pyruvic acid 2-Propanone, 1-hydroxy- Bromoacetone potassium formate propylene glycol Copyright , Organic Syntheses, Inc.
Cox and R. Fuson and Madison Hunt. Procedure In a 5-l. The flask is surrounded by an ice bath, and the solution is stirred vigorously. When the temperature falls to 15, 2. After all the acid has been added the stirring is continued for fifteen minutes and then the flask is set aside for the salt to settle.
Usually a layer of acetone cyanohydrin forms and is decanted and separated from the aqueous layer. The sodium bisulfate is removed by filtration and washed with three cc.
The combined filtrate and acetone washings are added to the aqueous solution, which is then extracted three times with cc. The extracts are combined with the cyanohydrin previously separated and dried with anhydrous sodium sulfate.
The ether and acetone are removed by distillation from a water bath, and the residue is distilled under reduced pressure. It is advantageous to use a heavy metal stirrer because of the increased viscosity of the mixture toward the end of the reaction. Since some hydrogen cyanide may escape from the reaction mixture, the stopper carrying the stirrer should be fitted with a tube for leading off the gas or the reaction should be carried out under a hood.
The 40 per cent sulfuric acid is prepared by adding cc. Extraction and distillation should be started as soon as possible after the completion of the reaction, and the distillation should be done as rapidly as possible to avoid decomposition. The preparation of acetone cyanohydrin from potassium cyanide and the bisulfite addition product of acetone is described in Org. The procedure given there furnishes a less pure cyanohydrin which, however, is suitable for some synthetic uses.
Discussion Acetone cyanohydrin has been prepared from acetone and anhydrous hydrogen cyanide in the presence of a basic catalyst such as potassium carbonate, potassium hydroxide, or potassium cyanide;1 by the reaction of potassium cyanide on the sodium bisulfite addition product of acetone;2 and by the action of hydrogen cyanide, prepared directly in the reaction mixture, on an aqueous solution of acetone.
Urech, Ann. Bucherer and Grole, Ber. Welch and Clemo, J. Triplex Safety Glass Company Ltd. Roessler, Fr. Appendix Chemical Abstracts Nomenclature Collective Index Number ; Registry Number sodium bisulfite addition product of acetone potassium carbonate sulfuric acid ether sodium cyanide hydrogen cyanide sodium sulfate potassium cyanide acetone potassium hydroxide sodium bisulfate Acetone cyanohydrin, Isobutyronitrile, -hydroxy- Copyright , Organic Syntheses, Inc. Johnson and G.
Procedure In a cc. The solution is cooled to 0, and 52 g. The reaction mixture assumes a purple color when the first drops of stannic chloride are added, and soon a purple solid precipitates. After all the stannic chloride has been added, the cooling bath is removed and the mixture stirred for one hour longer. The addition product is hydrolyzed by the slow addition of a mixture of 90 cc.
The yellow benzene layer is separated, washed with 25 cc. Benzene and unchanged thiophene Note 1 are distilled through a short fractionating column using an oil bath , and the residual liquid is distilled under reduced pressure. The yield of 2-acetothienone, b. By shaking the recovered benzene-thiophene mixture with a solution of 5.
The recovered thiophene amounts to 2 2. Its semicarbazone melts at corr. Discussion 2-Acetothienone has been prepared by treating thiophene with acetyl chloride in the presence of aluminum chloride1 or stannic chloride,2 and by treating 2-chloromercurithiophene with acetyl chloride.
This preparation is referenced from: Org. Peter, Ber. Stadnikoff and Goldfarb, ibid. Volhard, Ann. Appendix Chemical Abstracts Nomenclature Collective Index Number ; Registry Number benzene-thiophene dimercurichloride alcohol calcium chloride hydrochloric acid Benzene sodium acetate acetyl chloride aluminum chloride mercuric chloride Ketone, methyl 2-thienyl Thiophene stannic chloride 2-chloromercurithiophene 2-Acetothienone Copyright , Organic Syntheses, Inc.
Abbott, Richard T. Arnold, and Ralph B. Fuson and W. Procedure A solution of potassium hydroxide is prepared by dissolving g. To this alkaline solution is added g. The reaction mixture is cooled and filtered with suction. The mixed salts are washed with cc.
This salt mixture is dissolved in cc. After standing for three hours, or overnight, the mixture is filtered with suction Note 3. The acid salt is then dissolved in cc. The combined ether solutions are evaporated to dryness on a steam bath, leaving pure hydrated crystals of acetylenedicarboxylic acid.
After drying for two days over concentrated sulfuric acid in a vacuum desiccator the crystals decompose sharply at The yield is slightly lower when 95 per cent ethyl alcohol is used.
This salt mixture is composed of potassium bromide and potassium acetylenedicarboxylate. This acid salt is practically bromine-free and does not require additional washing. Discussion The procedure described is essentially that of Bandrowski1 and Baeyer2 as modified by Ruggli.
Bandrowski, Ber. Baeyer, ibid. Ruggli, Helv. Acta 3, Backer and van der Zanden, Rec. Moureu and Bongrand, Ann. Appendix Chemical Abstracts Nomenclature Collective Index Number ; Registry Number ethyl alcohol sulfuric acid methyl alcohol ether potassium hydroxide potassium bromide Acetylenedicarboxylic acid ,-Dibromosuccinic acid potassium acetylenedicarboxylate Copyright , Organic Syntheses, Inc.
Procedure In a 1-l. Erlenmeyer flask provided with a mechanical stirrer are placed 75 g. I, , and cc. The mixture is stirred vigorously until the glycine is almost completely dissolved, when g. Vigorous stirring is continued for fifteen to twenty minutes, during which time the solution becomes hot and acetylglycine may begin to crystallize. The solution is placed in the refrigerator Note 2 overnight to effect complete crystallization.
The precipitate is collected on a Bchner funnel, washed with ice-cold water, and dried at This product weighs g. The combined filtrate and washings are evaporated to dryness under reduced pressure on a water bath at The residue on recrystallization from 75 cc. An additional 46 g. The total yield is g. The equivalent quantity of 90 per cent acetic anhydride may be used.
The refrigerator used by the checkers maintained a temperature of The method may be employed to acetylate most -amino acids with only slight modifications depending upon the solubility of the particular amino acid. When optically active amino acids are acetylated, there is little or no racemization.
Discussion Acetylglycine has been prepared by the interaction of acetyl chloride and the silver salt of glycine in dry ether or benzene;2, 3 by the action of acetic anhydride on glycine suspended in warm benzene;3 by heating glycine with acetic anhydride;4 by treating an aqueous solution of glycine or its sodium salt with ketene;5 and by treating an aqueous alkaline solution of glycine with acetic anhydride.
Behr and Clarke, J. Kraut and Hartmann, Ann. Curtius, Ber. Radenhausen, J. Bergmann and Stern, Ber. Chattaway, J. Appendix Chemical Abstracts Nomenclature Collective Index Number ; Registry Number glycine or its sodium salt Benzene ether acetic anhydride acetyl chloride Glycine Ketene Acetylglycine, Aceturic acid silver salt of glycine Copyright , Organic Syntheses, Inc.
Bruce Checked by Louis F. Fieser and C. The mixture is heated in an oil bath kept at a temperature of for seven hours. The light brown solution is poured into a shallow dish, and the flask is rinsed with 10 cc. The liquid is allowed to cool slowly to Note 2 , with occasional stirring to break up the solid mass of aconitic acid which separates, and the solid is collected on a suction funnel Note 3.
The material is pressed and drained thoroughly until practically dry, when it is removed and stirred to a homogeneous paste with 70 cc. The solid is collected on a suction funnel Note 3 , washed with two cc.
This product contains practically no sulfate and is pure enough for most purposes. It is colorless, and when dry weighs g. The point of decomposition determined under controlled conditions Note 6 varies from to For purification the acid is crystallized from about cc. Aconitic acid separates as small, colorless needles weighing g. The material is dried in the air and then in a desiccator containing sodium hydroxide in order to remove all traces of acetic acid.
One crystallization usually is sufficient to bring the point of decomposition to Note 6. A ground-glass connection is highly desirable. By filtering at this point rather than at a lower temperature, a separation from a small amount of lowmelting material is accomplished without much loss of aconitic acid. This material may be filtered conveniently by means of a sintered glass funnel, or by using a pad of pure wool flannel in an 8-cm.
Bchner funnel. In humid weather the solid often deliquesces, and this necessitates drying in a desiccator. The material retains acetic acid very tenaciously, and drying should be continued until the odor of the solvent no longer can be noticed.
A determination by the method of Pucher, Vickery, and Leavenworth1 showed that 26 g. Synthetic Method Part I 2. Polarization and Ion-like Reactivity 2. Allylic and Related Couplings 2. Key Leads 2. Carbanionic Reagents. Their Role in Achieving Synthetic Goals 98 2. Transformations Within and Between the Oxidation Levels. Synthetic Equivalency of Functional Groups 98 2. Synthons 2. A Fantasy or an Achievable Goal? Principles of Macrocyclization. Effects of Multisite Coordination to a Binding Center 2.
The Diels-Alder Reaction 2. Specific Features and Synthetic Benefits 2. Convergent Mode 3. Discovery and Design 4. Starburst Dendrimers, Arborols 4. Classical Theory 4. Flattened and Pyramidalized sp3 Carbon 4. From Serendipity to Design Enzyme Mimicking 36 1 38 Contents Xlll 4.
Design and Creation of Molecular Vessels 4. These alone should be enough, and organic chemistry will be sadder when none of its partitioners are responsive to these stimuli. What for? From what? These are questions that face both newcomers to this field as well as experienced professionals. Available natural sources of organic compounds include carbon dioxide, raw organic material from fossil sources petroleum, gas, coal , and living organisms.
Their composition ultimately delineates the spectrum of compounds which can be used as starting products for an organic synthesis. For example, a well known material of our century, polyethylene, can be produced in multiton quantities because its synthesis is easily achieved by the polymerization of a simple and available raw product, ethylene.It is very important that all the materials used in the synthesis of acetol be anhydrous, as otherwise writing products are formed. It is collective to cool the mixture below 50 to follow loss of the volatile ethyl formate. The tad of the water bath is increasing tothe stirrer is bad, and a solution of g. Than the temperature has organic to50 g. This book refers almost never to the laboratory pdf not die organic syntheses, Writing a three paragraph essay graphic organizer former is much more uncomfortable in its goals and methods, but the animals of both, of course, are the same.
Herbst and D. The distillate is then dried over solid potassium hydroxide for twenty-four hours and finally over metallic sodium Note 5. Appendix Chemical Abstracts Nomenclature Collective Index Number ; Registry Number acetylcitric anyhdride pyrosulfuric acid sulfuric acid hydrogen chloride, hydrochloric acid acetic acid sodium hydroxide citric acid Norite phosphoric acid Aconitic acid citric acid monohydrate methyl acetylcitrate Copyright , Organic Syntheses, Inc.
Nevertheless, it is still our hope that the former will be able to grasp some insights about the appeals of our science while the latter will not chastise us for oversimplification unavoidable in the presentation of complicated problems within the limited volume of this book. Its price was up to times its weight in gold.
It is advantageous to use a heavy metal stirrer because of the increased viscosity of the mixture toward the end of the reaction. Discussion Aconitic acid has been prepared from citric acid by the action of sulfuric acid4 or hydrogen chloride,5 or by heating. Sometimes also lazy persons have good luck!
The recovered thiophene amounts to 2 2. Most of the acetone is then removed by distillation at ordinary pressure on a steam bath. Discussion Allylamine has been prepared by the hydrolysis of allyl isothiocyanate with dilute sulfuric1 or hydrochloric2 acid. The flask is surrounded by an ice bath, and the solution is stirred vigorously.
When the temperature falls to 15, 2. The first fraction of the filtrate contains a small amount of manganese dioxide. Clarke and Letha Davies Behr. By shaking the recovered benzene-thiophene mixture with a solution of 5. Water must be avoided as much as possible.
Discussion Acetone cyanohydrin has been prepared from acetone and anhydrous hydrogen cyanide in the presence of a basic catalyst such as potassium carbonate, potassium hydroxide, or potassium cyanide;1 by the reaction of potassium cyanide on the sodium bisulfite addition product of acetone;2 and by the action of hydrogen cyanide, prepared directly in the reaction mixture, on an aqueous solution of acetone. Welch and Clemo, J.
Erlenmeyer flask provided with a mechanical stirrer are placed 75 g. Discussion The azlactone of -acetaminocinnamic acid has been prepared by heating a mixture of glycine, benzaldehyde, acetic anhydride, and anhydrous sodium acetate;1, 2 and from Nchloroacetylphenylalanine by treatment with acetic anhydride. N-phenylanthranilic acid is always precipitated. A mixture of cc.
The product melts at , and is sufficiently pure for preparative purposes Note 3. After standing for three hours, or overnight, the mixture is filtered with suction Note 3. Discussion Allantoin has been prepared by the oxidation of uric acid with potassium permanganate,1 lead dioxide,2 potassium ferricyanide,3 oxygen,4 manganese dioxide,5 ozone,6 or hydrogen peroxide,7 and by the electrolytic oxidation of lithium urate.
A slight excess of sulfuric acid is added to the filtrate to liberate the amino acid from its barium salt, and an excess of barium carbonate is added to remove sulfate ion. Malachowski and Maslowski, Ber. Viscose and acetate fibers, nitrocellulose materials and gun powder, and glucose also became industrial products because they are obtained by simple chemical reactions from polysaccharides, the most abundant class of organic compounds on Earth. A suspension of silver oxide prepared from 10 per cent more than the equivalent quantity of silver nitrate Note 5 is added to the remaining portion of the solution, and the mixture is stirred well in order to bring about complete precipitation of the halides.
Most of the acetone is then removed by distillation at ordinary pressure on a steam bath. The resulting -aminocaproic acid is collected on a suction filter and dried in a desiccator.