Constitutional formulas

The presence of alkaloids in Lobelia injlata, Linn., was first recorded by Proctor. Lobeline was prepared by Lewis as a basic oil from which Siebert made and analysed a series of salts and proposed the formula, CigHjsOjN. In 1921 Bohringer and Sohne protected a process for the isolation and separation of three alkaloids, a-, 3 and y-lobelines. In the same year Wieland published the first of a series of papers in which is described the isolation of several groups of alkaloids, to most of which constitutional formulae have been assigned and, in some cases, confirmed... 

The chief descriptive characters and reaction products of the lelobine series are recorded in Table B, and those of the lobinine group in Table C. The constitutional formulas assigned to the principal members of each group are shown on p. 32. 

KETONES OF THE MORPHINE GROUP. As these substances have played an important part in the discussion of constitutional formulae for the morphine group and the allied alkaloids, it is desirable to describe the more important of them. 

ALKALOIDS OF OTHER PAPAVER SPP. For the following papaveraceous alkaloids neither constitutional formulas nor group relation-... 

Geraniol is a colourless liquid of sweet odour, recalling that of the rose, principally, and to a lesser extent the pelargonium. It is an open-chain alcohol, having one of the two following constitutional formulae -t-... 

Camphene hydrate is a tertiary alcohol, and a study of its characters and method of preparation caused Aschan to consider that it is improbable that borneol and isoborneol are stereoisomeric, but that they probably have different constitutional formulae. 

Konstanz, n. constancy, konstatieren, v.t. ascertain, establish, verify. Konstellation, /. constellation configuration, arrangement (as in microstructure), konstituieren, v.t. constitute. Konstitutions-formel, /. constitutional formula. 

Fig. 2.12. Relationship between sample domain and signal domain in element analysis (a) and structure analysis (b). The representation in the sample domains is shown in different forms, as a block diagram and a list in case of (a) and as constitution formula and structure matrix, respectively, in case (b)...

Although many suggestions have been advanced for the structure of lignin (15), establishment of a valid constitutional formula for this substance is still far from realized. It was considered (67) that the building stones of lignin are linked together by a methylene dioxv bridge... 

During the course of the nineteenth century, organic chemists developed a complex and integrated theory of chemical identity and constitution that in eluded theories of chemical atoms and equivalents, radicals, substitution, types, and valence, eventually unified in the so-called structure theory of constitutional formulas. But by midcentury, there was some discontent among chemists about the limitations of the overall theoretical framework within which they were working. 

On this occasion, Brodie clearly interchanged the roles in chemical explanation of the rational or constitutional formula and the molecular model, because the rest of his lecture is a critique of the formula. 

But what is the meaning of this edifice It was easy to deny that constitutional formulas in two dimensions represented chemical "reality." After all, molecules could hardly exist in just two dimensions.93 The French school of chemistry was clear on this point, beginning with Laurent, who wrote, "The formula represents the functions of the compound, "94 a point of view shared by Wurtz and Edouard Grimaux. Wurtz claimed that "these formulas. . . do not give any indication on the form of the molecule in space." 95 Similarly,... 

The constitution is customarily represented by constitutional formulas, i.e. by labelled graphs whose nodes are the atoms, and whose connecting lines are the bonds. Nodes are labelled by chemical element symbols and can carry further symbols for electrons and electrical charges. 

The information contained in a constitutional formula can also be given in terms of a connectivity list. Such a list tells which atom is connected to which (the formal bond orders are indicated, if needed). The statement that a C-atom is connected to another C-atom does not suffice, if there is more than one C—C-bond, but the bonded partners must be indicated individually. The connectivity list of 1 serves as an illustration. 

It is possible to consider first the coordination numbers, and then the atomic numbers, or to proceed in the reverse order. If there are more differences in atomic numbers than in coordination numbers the first mode is more effective, while the existence of many atoms of the same element with different coordination number favors the use of the second. Most atoms of a given chemical element have the same coordination number, particularly in organic compounds. If the H-atoms are, however, disregarded, one obtains constitutional formulas which can be indexed quite well by primary consideration of the degrees of the nodes0), i.e., the number of immediate covalent neighbors. 

The Morgan algorithm 5> is a device used by the Chemical Abstracts Service for assigning indices to the nodes of constitutional formulas whose H-atoms have been omitted, i. e. their reduced graphs. If the indices of all atoms are needed, e.g. for the representation of stereochemistry, an additional procedure is needed for establishing those for the H-atoms. Constitutional symmetry is not indicated directly by Morgan indices. 

An FIEM(A), the family of isomeric ensembles of molecules of A, is the set of all EM(A), Thus, an FIEM is described simply by a gross, empirical formula an EM is described by a list of molecular species in terms of constitutional formulas. The constitutional chemistry of a set of atoms A can be described by the structure of its FIEM(A). 

These syntlieses give no indication as to the structure of aspartic acid, the constitutional formula of which is based upon Kolbe s work, that it is amino-succinic acid the only synthesis of aspartic acid which confirms this constitution appears to be that by Piutti in 1887. Sodium oxalacetic ester, prepared from oxalic ester and acetic ester in the presence of sodium ethylate —... 

FIGURE 32. Constitution formula of triterpene-derived hydroperoxide 78 ... 

FIGURE 33. Constitution formula of the acetogenin oxanthromicin (79) and its tetramethyl derivative 80 ... 

Such, then, being the constitution of ethylidene and ethylene, it follows that the former ought to give rise to an acid of the constitution shown in formula No. 1, whilst ethylene should produce an acid agreeing with formula No. 2. The acids actually produced from these sources are lactic and pandactic adds hence No, 1 is the constitutional formula of lactic acid, and No. 2 that of paralactic acid,—a conclusion which harmo nizes perfectly with all the reactions in which the production... 

The third of the above formula is that of ethyl-glyooUic acid. Of the possible acids containing five atoms of carbon, only two, vis. etbomethoxalio acid and valerolactio acid, are known. The cause of the isomerism of these two acids is seen at once from an inspection of their constitutional formula... 

Jbrmofioa.—-1. By the Mtlon of potassic hydrate uponethy lenic cyanide (p. 289) this reaction proves that sucoinic acid contains ethylene, and that its constitutional formula is as above given but an isosuccinic arid must be capable of formation, though hitherto never obtained. This acid will obviously cont n otbylidene in the place of ethylene mid its fOOHo... 

The following is a list of the names, constitutional formula), and boiling-points of those ketones which are best known... 

In 1893 Werner founded his new constitutional formula for inorganic compounds, applied the theory to the systematic classification of the chromi-ammines, and found that all the chromi-ammines which had been investigated could be fitted in to his system of classification. Since then the chemistry of the chromi-ammines has been further developed hv Werner, Pfeiffer, and many others relationships have been traced between chromi-ammines, complex salts, and chromic salt hydrates, and numerous cases of isomerism have been discovered in this series of ammines. 

As the various theories of the constitution of the metal-ammines have been discussed,1 only the constitutional formulae for these compounds, adopted at the present time, will be used. 

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