Hey! Finally was able to isolate the dimethly ether of gallacetophenone. Here is what the TLC looked like
Apparently the reactant (right in the tlc) has converted almost completely to the product. The reaction conditions were as follows :
3.36 gm of gallacetophenone(0.02 moles) and 15.8 gm (0.1 mole) was added in 100 ml acetone and refluxed for 20 mins. The reaction mixture was cooled to room temperature. To this, 2.52 grams(0.02 moles) of dimethyl suflate was added and stirred for 3 hours. The reaction did not seem to progress. So the reaction was heated for about 1 hour at reflux. The reaction flask was kept under free stirring for 48 hours and the TLC shown above was taken. Apparently the reaction had proceeded. The spot with the reactant is almost gone. There is a faint spot of the mono methyl ether just below the main dark spot. The trimethyl ether is seen distinctly above the monomethly ether.
Workup : The acetone was distilled off to leave only 10 % of the solution. To this about 50 ml toluene was added and the reaction mixture was washed with almost 100 ml (25ml x 4) of 20% NaOH. This was done so that only the mono and di methly ethers would remain in the solution. These were then to be separated by column chromatography. Hope you guys find it useful 
Hi Friends,
I am getting quite busy with my schedule, which is the reason I am not getting time to write my experiments. I will try to write them as soon as possible. Don’t worry I have them jotted down in my notes, but just not on the mahine. I will hopefully get them typed or probably write it on my own. Things are going good… Had my first chemical kick yesterday… The material frothed out of the condenser . Anyways, wish me luck guys!! Bye!
JPV
Found a convinient methylation process. Going to try out that agaisnt the one with methly iodide… Here is the process…
Gallacetophenone 3,4-dimethyl ether
To a boiling mixture of gallacetophenone (16.8g, 1 mol), benzene (400 mL) and anhydrous K2CO3 (55g) was added methyl sulphate (26.5g, 2.05 mol) in one portion, and the whole refluxed for 6 h with occasional shaking. After the addition of water (750 mL) and shaking, the benzene layer was separated and shaken several times with NaOH solution, and the alkaline extracts solidified. The precipitated gallacetophenone 3,4-dimethyl ether after crystallisation from MeOH had mp 75-77°C (yield 10g) (for previous methods of preparation from gallacetophenone, see Perkin9, Perkin and Wilson10, David and von Kostanecki11).
I found this interesting. I think it should be easier 
. The work up is much easier. No column atleast
Today was a good day! I learned a lot from the research reactions that I have been carrying out. Its really a great learning exprience. Okay, today what I did was methylation of my product that I have synthesized earlier. I have described the product synthesis here. Let me call the reactant “A”. Okay, here is what I did. I took up 5 ml of acetone in a test tube. I took about 0.5 g of “A” in the test tube. The compound got dissolved and formed a light yellow solution. To that, about 0.2 g of K2CO3 was added. This resulted into a little bit of extra K2CO3 remaining undissolved. The test tube was shaked vigorously and I tried to make sure that the K2CO3 dissoved as much in the reaction mixutre as possible. After about 5 minutes of vigorous shaking and breaking of K2CO3 with a glass rod, quite a bit of K2CO3 had dissolved. After that about 0.2 ml of methyl iodide was added to the reaction mixture. This resulted into deepening of the yellow colour of the reaction mixture. The temperature of the test tube rose by about 1 C. I will check the results of the tests by tomorrow. Hopefully, it would give me something to cheer about!
Here pyrogallol reacts with Acetic Anhydride in presence of Zinc Chloride (Lewis Acid) and acetic acid as a solvent.
Pyrogallol:
- IUPAC Name: benzene-1,2,3-triol
- Chemical Formula: C6H6O3
- Exact Mass: 126.03
- Molecular Weight: 126.11
- m/z: 126.03 (100.0%), 127.04 (6.7%)
- Elemental Analysis: C, 57.14; H, 4.80; O, 38.06
- Boiling Point: 309°C
- Melting Point: 131-134 °C
- Critical Temp: 792.92 [K]
- Critical Pres: 99.8 [Bar]
- Critical Vol: 311.5 [cm3/mol]
- Gibbs Energy: -342.18 [kJ/mol]
- Log P: 0.87
- MR: 30.72 [cm3/mol]
- Henry’s Law: 12.61
- Heat of Form: -451.1 [kJ/mol]
- tPSA: 60.69
- CLogP: 0.211
- CMR: 3.1479
Gallacetophenone:
- IUPAC Name: 1-(2,3,4-trihydroxyphenyl)ethanone
- Chemical Formula: C8H8O4
- Exact Mass: 168.04
- Molecular Weight: 168.15
- m/z: 168.04 (100.0%), 169.05 (8.9%), 170.05 (1.2%)
- Elemental Analysis: C, 57.14; H, 4.80; O, 38.06
- Boiling Point: 705.05 [K] (Calc)
- Melting Point: 171-172 °C
- Critical Temp: 828.83 [K]
- Critical Pres: 76.28 [Bar]
- Critical Vol: 429.5 [cm3/mol]
- Gibbs Energy: -463.89 [kJ/mol]
- Log P: 0.18
- MR: 41.97 [cm3/mol]
- Henry’s Law: 15.35
- Heat of Form: -616.43 [kJ/mol]
- tPSA: 77.76
- CLogP: 0.861434
- CMR: 4.1112
Synthetic Procedure:
In a 250-cc. round-bottomed flask, fitted with a reflux condenser, 28 g. (0.21 mole) of freshly fused zinc chloride is dissolved in 38 cc. of glacial acetic acid by heating in an oil bath at 135–140°. Try to make sure that the quality of Zinc Chloride used is good. It is always preferred to freshly fused Zinc Chloride. The temperature of the solution remains close to about 132 °C. Once the temprature reaches this point, forty grams (0.37 mole) of 95 per cent acetic anhydride is then added to the clear, pale brown liquid, followed by the addition in one lot of 50 g. (0.4 mole) of distilled pyrogallol. The addition should be done only after about 30 minutes of free stirring of pale brown liquid. The mixture is heated at 140–145° (Note 3) for forty-five minutes with frequent and vigorous shaking. Once again, due to the acetic acid synthesized in the reaciton, the temprature of the flask should not exceed 138 °C. You can try to maintain the bath temperature at 150°. The unused acetic anhydride and acetic acid are removed by distilling under reduced pressure. The temperature should NOT exceed 150 °C. The red-brown cake is broken up by the addition of 300 cc. of water with mechanical stirring for a few minutes. The mixture is cooled in ice water, filtered with suction, and washed with cold water. The crude material, 45–50 g., is crystallized from 500 cc. of boiling water saturated with sulfur dioxide. The yield of straw-colored needles melting at 171–172° is 36–38 g. (54–57 per cent of the theoretical amount). On saturating the mother liquor with salt and cooling to 10°, 4–5 g. of crude material is obtained, which on recrystallization yields 3–4 g. of pure material.
The method described above is a modification of the process of Nencki and Sieber. Gallacetophenone has also been prepared by treating pyrogallol with acetyl chloride, and from 2-formyl-4-acetylresorcinol by treatment with hydrogen peroxide and alkali.
Related References:
- Witt and Braun, Ber. 47, 3227 (1914).
- Cheema and Venkataraman, J. Chem. Soc. 1932, 919.
- Nencki and Sieber, J. prakt. Chem. (2) 23, 151, 538 (1881);
- Nencki, Ber. 27 2737 (1894).
- Crabtree and Robinson, J. Chem. Soc. 121, 1038 (1922).
- Einhorn and Hollandt, Ann. 301, 107 (1898);
- Fischer, Ber. 42, 1020 (1909).
- Nakazawa, J. Pharm. Soc. Japan 59, 297 (1939) [C. A. 33, 8186 (1939)].
What I am going to do from now on, is probably write down every thing I research. I will try to be as regular as I can be in the course of my writing. Let me begin with writing about the reaction that I carried out the other day. See you soon!
We wish to develop a notation that will permit us to state a generalized selection rule summarizing the conclusions of the pericyclic theory.
Local Symmetry and Interaction Topology
We have taken care to emphasize in the discussion that the important symmetry is the local symmetry of the part of the molecule actually involved in the reaction. We have already given in Section 11.1 a justification for this course; another example is appropriate here, now that we have gained an appreciation of the role of orbital symmetry in pericyclic reactions. In Equation below,
the substitution of a methyl for one hydrogen on the diene 11 destroys the symmetry. Now a mirror plane reflection (for disrotatory closure) or twofold rotation axis (for conrotatory closure) is no longer a symmetry operation. No symmetry element remains to provide a distinction among different orbitals.22 Yet we know fromthe success of ? electron and localized bonding pictures of molecules that the methyl group should have at most a secondary influence. It is clearly the topology of the interactions among the basis orbital functions that should determine the course of the reaction. The inherent symmetry of this topology, shorn of minor disturbances by substituents or by distortion, is the symmetry with which we need be concerned. The examples we have used to illustrate the ideas of orbital symmetry control serve a useful function because they allow us to visualize that inherent symmetry in terms of the molecule as a whole. But we can as well abstract the essential features of the pattern of orbital interaction by discarding altogether the molecular framework and keeping only the pericyclic reacting orbitals. This argument justifies the Woodward and Hoffmann stipulation (p. 586) that a pericyclic process must be reduced to its highest inherent symmetry for analysis.
Interaction Diagrams
In order to develop this idea further, we adopt an approach similar to that of DewarZ3 and introduce the orbital interaction diagram as a topological notation for paths of interaction amongst basis orbitals in pericyclic processes. We depict an orbital system by a schematic drawing of the basis orbitals, and use a short curved line to indicate interaction between two orbitals. When we wish to
distinguish interactions present in starting materials from those in products, we use dotted lines for the former and solid lines for the latter; we call such a picture a directed orbital interaction diagram, or, more briefly, a directed diagram. When the distinction is unimportant, solid lines serve throughout and the result is the orbital interaction diagram or, more simply, the interaction diagram. A closed loop of interconnected orbitals then symbolizes the pericyclic process. By way of example, Structure 12 shows the ethylene .rr bond in this convention; 13 would be hexaInteraction Diagrams In order to develop this idea further, we adopt an approach similar to that of DewarZ3 and introduce the orbital interaction diagram as a topological notation for
paths of interaction amongst basis orbitals in pericyclic processes. We depict an orbital system by a schematic drawing of the basis orbitals, and use a short curved line to indicate interaction between two orbitals. When we wish to distinguish interactions present in starting materials from those in products, we use dotted lines for the former and solid lines for the latter; we call such a picture a directed orbital interaction diagram, or, more briefly, a directed diagram. When the distinction is unimportant, solid lines serve throughout and the result is the orbital interaction diagram or, more simply, the interaction diagram. A closed loop of interconnected orbitals then symbolizes the pericyclic process. By way of example, Structure 12 shows the ethylene .rr bond in this convention; 13 would be hexatriene; 14 a a bond between two centemZ4 We note first that the arrangement of orbitals and their orientations are unimportant; we assume that we have examined
the structures of reactant and product and have determined which basis orbitals to use and what the significant interactions are; thenceforth we need maintain only the topology intact. Thus 15 and 16 are entirely equivalent to 14;
There are several transformations that are conceptually related to carbene reactions but do not involve carbene, or even varbenoid intermediates. Usually these are reactions in which the generation of a carbene is circumcented by a concerted rearrangement process. An important example of this type of reaction is the thermal and photochemical reactions of ?-diazoketons. When ?-diazoketons are decomposed thermally or phtochemically, the usually undergo rearrangement to ketenes. This reaction is known as Wolff Rearrangement.
If this reaction procedes in a concerted fashion, a carbene intermediate is avoided. Mechanistic studies have been aimed at determining if migration is concerted with loss of nitrogen. The conclusion that has emerged is that a carbene is generated in photochemical reactions but the reaction can be concerted under the thermal conditions. A realted issue is weather the carbene, when involved, is in equillibrium with a ring closed isomer, and oxirene. this aspect o the reaction has been probed by isotopic labelling. If a symmetrical oxirene is formed, teh label should be distributed to both the carbony carbon and the ?-carbon. A concerted reaction or a carbene intermediate that did not equillibriate with the oxirene should ahve been only in the carbonyl carbon. The extendt to which teh exorene is formed depends upon the structre of the diazo compound. For diazoacealdehyde, photolysis leads to only 8% migration of label which would correspond to the formation of 16% product through oxirene.
The diphenyl analog shows about 20-30 % rearrangement. ?-Diazocyclohexanone gives no evidence of an oxirene intermediate, since all the label remains at the carbonyl carbon.
The main synthetic application of Wolff rearrangement is for the one-carbon homologation of carboxylic acids. In this procedure, a diazomethyl ketone is syntehsized from an acyl chloride. The rearrangement is then carried out in a nucleophilic solved which traps the ketene to form a carboxylic acid or an ester. Silver oxide is often used as a catalyst because it seems to promote the rearrangement over carbene formation. The photolysis of ?-diazoketons results in ring contraction to a ketene which is usually isolated as the corresponding ester.
The hydrogen atomic orbitals would not do us a great deal of good if orbitals of other atoms were radically different, since in that case different pictures would be required for each atom. But the feature of the hydrogen atom problem that determines the most important characteristics of the hydrogen atom orbitals is the spherical symmetry. Since all the atoms are spherically symmetric, the atomic orbitals of all atoms are similar, the main difference being in their radial dependence, that is, in how rapidly they approach zero as one moves away from the nucleus. Because the radial dependence is of minimal importance in qualitative applications, one may simply use orbitals of the shapes found for hydrogen to describe behavior of electrons in all the atoms.
Ground and Excited States
We know that an electron ina hydrogen atom in a stationary state will be described by one of the atomic orbital functions ?1s, ?2s,?2px and so forth. We can make this statement in a more abbriviated form by saying that the electron is in one of the orbitals ?1s, ?2s,?2px,…, and we use this more economical kind of statement.
The orbital that has associated with the lowest energy is ?1s if the electron is in this orbital, it has the lowest total energy possible, and we say that the atom is in its electronic ground state. If we were to give more energy, say enough to put it to ?2px orbital, the atom would be in an electronic excited state. In general, for any atom or molecule, the state in which all the electrons are in teh possible energy orbitals is the electronic ground state. Any higher energy state is called an electronic excited state.
Lewis structures serve admirably for many aspects of mechanistic organic chemistry. Frequently, however, we need a more accurate bonding model.
Models Based on the Quantum Theory
The description of chemical bonding must ultimately be based on an understanding of the motions of electrons. In order to improve our model, we need to appeal to the quantum theory, which summarizes the current understanding of the behavior of particles of atomic and subatomic size. The quantum theory provides the mathematical framework for describing the motions of electrons in molecules. When several electrons are present, all interacting strongly with each other through their mutual electrostatic repulsion, the complexity is so great that exact solutions cannot be found. Therefore approximate methods must be used even for simple molecules. These methodstake various forms, ranging from complex ab initio calculations, which begin from first principles and have no parameters adjusted to fit experimental data, to highly approximate methods such as the Hiickel theory, which is discussed further in Appendix 2. The more sophisticated of these methods now can give results of quite good accuracy for small molecules, but they require extensive use of computing eq~ipmentS.~uc h methods are hardly suited to day-to-day qualitative chemical thinking. Furthermore, the most generally applicable and therefore most powerful methods are frequently simple and qualitative. Our ambitions in looking at bonding from the point of view of the quantum theory are therefore modest. We want to make simple qualitative arguments that will provide a practical bonding model.
Atomic Orbitals
The quantum theory specifies the mathematical machinery required to obtain a complete description of the hydrogen atom. There are a large number of functions that are solutions to the appropriate equation; they are functions of the x, y, and z coordinates of a coordinate system centered at the nuc l eu~E.~ac h of these functions describes a possible condition, or state, of the electron in the atom, and each has associated with it an energy, which is the total energy (kinetic plus potential) of the electron when it is in the state described by the function in question. The functions we are talking about are the familiar Is, 2s, 2P, 3s,. . . atomic orbitals, which are illustrated in textbooks by diagrams like those in Figure 1.1. Each orbital function (or wave function) is a solution to the quantum mechanical equation for the hydrogen atom called the Schrodinger equation. The functions are ordinarily designated by a symbol such as ?, ?, ?, and so on. We shall call atomic orbitals ?, or ?, and designate by a subscript the orbital meant, as for example ?1s, ?2s, and so on. Later, we may abbreviate the notation by simply using the symbols Is, 2s, . . . , to indicate the corresponding orbital functions. Each function has a certain numerical value at every point in space; the value at any point can be calculated once the orbital function is known. We shall never need to know these values, and shall therefore not give the formulas; they can be found in other source.
The important things for our purposes are, first, that the numerical values are positive in certain regions of space and negative in the other regoins and second, that the value of each function approaches zero as one moves farther from the nucleus. In the figure above the positive regions are shaded and negative ones are unshaded.
Imagine walking around inside an orbital and suppose that there is some was of sensing the value – positive, negative and zero – of the orbital function as you walk from point to point. On moving from a positive region to a negative region, you must pass through some point where the value is zero. The collections of all the adjecent points at which the function is zero are called nodes. They are the surfaces in the three dimensional space ans most important ones for our purposes are like those shown in the figure above for p and d orbitals illustated. Nodes can also be spherical and of other shapes, but these are of less concern to a chemist.
The Physical Significance Of Atomic Orbital Function
The fact that an orbital function ? is of different algebraic sign in different regions has no particular physical significance for the behavior of an electron that finds itself in the state defincd by the orbital. (We shall scc shortly that the significance of the signs comes from the way in which orbitals can be combined with each other.) The quantity that has physical meaning is the value at each point of the function ?2, which is positive everywhere, since the square of a negative number is positive. the squared function, ?2, gives the probability of finding the electron at various points in the space. Diagrams like that in the figure below, with the shading of vairous regions or, more succinictly, the electron distribution or electron density, are actually pictures of ?2, and not ? itself. The general shape of ?2 will be similar to the shape of ?. the orbitals and their shapes have no edges, even though definite outlines are usually drawn in the diagrams. The values merely approach closer and closer to zero as one goes away from the nucleus.
