Petroleum, natural gas, and coal are presently employed not only as raw materials but primarily as sources of energy. One of the most pressing needs is to disengage this double function and to better utilize fossil resources. Possible solutions are demonstrated by means of plastics (a breakdown of oil consumption in the Federal Republic of Germany in 1976 is shown on the right).

In a stoke of genius, Berzelius created the formula language of chemistry over 100 years ago. This language has hardly changed since then. However, it is just not informatic enough to deal with inorganic solid state compounds, and more recent proposals also appear rather inadequate. The article closes with a call for a new Berzelius.

The first 14-membered ring found in sulfur chemistry is present in S₁₀(CO)₄ (1). This compound is stable at room temperature; it forms yellow crystals and exists in the expected conformation.

1,4-Dioxanes perfluorinated at C² and C³ of type (4) are accessible from dicarbonyl compounds (1), ethylene dimesylate (3), and KF (1:1:2). The synthesis can be generalized (M = methanesulfonyl; R_f, R′_f = F, CF₃).

Reactions of RSH with diketene (1) are highly dependent upon the reaction conditions. Acid-catalyzed reaction of alkanethiols with (1) leads, like the photo or radical reaction, to the lactone (2). This could not be deduced from previous findings. (2) reacts with alcohols to give γ-(alkylthio)crotonic esters.

Reactions of typical transition metals with alkyl halides normally take place only after prior chemical or physical activation of the metals. It is now possible to bring about reaction of commercial grade Fe, Co, and Ni powder with perfluoroalkyl iodides (RI) under mild conditions: In the presence of SO₂, the alkanesulfinates (1) with a dinuclear cation are formed in dimethylformamide at room temperature.

1,5,5-Trifunctionalized pyrrolizidines are formed via ring expansion from the β-lactam (1) in the presence of NaOCH₃. The action of acids produces the salt (2). Sterically uniform 1,5-pyrrolizidinedicarboxylic acid can be obtained from the ester (3).

4,5-Dichlorinated imidazoles (1) having an unsubstituted N atom were not previously accessible by a general synthesis. It has now proved possible to produce numerous derivatives (1) in useful yields by synthesis from aldehydes, cyanogen, and hydrogen chloride, thus permitting a study of their reactions.

β-Substituted acrylonitriles (4) and (5) are formed in a novel reaction from the oxathiazine derivatives (3) via ring opening and elimination of SO₃. The reactants (3) are in turn accessible in several steps from the ketones (1) having an α-CH₂ group. Step (2) → (3) is also new.

Epoxidation of phospholene oxides (1) to give (2) proceeds almost quantitatively by the route shown below, thus superseding previous methods. There is no need to isolate the intermediate (2). An X-ray structure analysis has been performed on one of the stereoisomers of (2a), R¹ = OCH₃, R² = R³ = CH₃.

Alkylphosphonic anhydrides such as (1) are recommended as condensation reagents for peptide synthesis. One advantage of (1) over dicyclohexylcarbodiimide (DCC) is that no sparingly soluble secondary products are formed. With regard to yield and degree of racemization, the new method is just as good as improved DCC techniques, and in some cases superior.

The skeleton (4) of tetrahydrocannabinol having translinked rings A and B can be obtained optically pure from the diketone (1) and (R)-citronellal (2). The key step is intramolecular Diels-Alder reaction (up to 20°C!) of the heterodiene intermediate (3).—Derivatives of (4) are of interest, e.g., in the treatment of glaucoma.

Citrate synthase, an enzyme of the tricarboxylic acid cycle, catalyzes the formation of citrate and coenzyme A from acetyl CoA and oxalacetate. In order to establish whether citryl CoA is formed as a true intermediate on the synthase, the analogue (1), R¹ = CH₂SCoA, R² = H, has been synthesized (citryl CoA contains CO in place of CH₂). Kinetic measurements showed that (1) acts as a strong inhibitor.

A nitrogen analogue of the hitherto unknown cyclobutane tetraone, the title compound (2), is formed as red-violet crystals from the phosphorane (1) and nitrobenzene in a one-pot reaction. The arrangement of phenyl groups indicated in the formula is confirmed by X-ray structure analysis. (2) is reduced, e.g. by phenylhydrazine, to (3), the first amidine of squaric acid whose N atoms are not linked in a ring.

Triazole derivatives (3) having a fungicidal action have been prepared by addition of triazole (2) to the α,β-unsaturated dicarbonyl compounds (1). The corresponding pyrazole derivatives are ineffective.

Tetrachlorovinylcarbene, ClC̈CClCCl₂, is unexpectedly formed on reaction of tetrachlorocyclopropene (1) with alkenes (2), in which the adducts (3) can be isolated. As shown by numerous examples, this type of reaction can be generalized, e.g. for synthesis of acids and esters (3), R¹ = CO₂H and CO₂R, having potential as insecticides.

Reactions of hexahydroporphyrins in the absence of air are strongly influenced by metal ions. Thus the tetrapyrrolic porphyrinogen (1), R = C₂H₅, reacts in the presence of Co²⁺ via several steps, including isobacteriochlorins (2), to give the hemicorrinoid dipyrrolic compounds (3). These are tautomers of (1). In the presence of Ni²⁺, (1) form complexes of the new hemicorrinoid-pyrromethenic system (4). ttct-(4) and tttt-(4) were characterized by their spectra and also by X-ray structure analysis. (The species ttt-(2), ttt-(3), and tttt-(4) likewise formed are not included in the scheme below.)

Reactions of hexahydroporphyrins in the absence of air are strongly influenced by metal ions. Thus the tetrapyrrolic porphyrinogen (1), R = C₂H₅, reacts in the presence of Co²⁺ via several steps, including isobacteriochlorins (2), to give the hemicorrinoid dipyrrolic compounds (3). These are tautomers of (1). In the presence of Ni²⁺, (1) form complexes of the new hemicorrinoid-pyrromethenic system (4). ttct-(4) and tttt-(4) were characterized by their spectra and also by X-ray structure analysis. (The species ttt-(2), ttt-(3), and tttt-(4) likewise formed are not included in the scheme below.)

A model substrate for studies in the hexahydroporphyrin series, i.e. the title compound (1) having C_2v symmetry, has been prepared by a multistep de-novo synthesis from a cyanosubstituted thiolactam. Catalytic hydrogenation of (1) affords the highly O₂-sensitive 2,3,7,8,15,24-hexahydro derivative; attempts to incorporate metal ions into this species lead to complexes of the 1,2,3,7,8,20-hexahydro isomer.

The 1,2-addition of R₂Al groups to diphenylacetylene can also be accomplished as a photoreaction. Depending upon R and the temperature, trialkylaluminum compounds (R₃Al)_n and Ph₂C₂ afford the heterocycle (2) [via (1)] and/or the trans-adduct (3). The photoisomerization (3) → (1) does not occur.