B. Willhalm’s research while affiliated with Ames Research Center and other places

The dye-sensitized photooxygenation of (–)-thujopsene (1) leads to two allyl hydroperoxides 16 and 17 (ratio 2:1). From the structure of the corresponding alcohols 2 and 3 it is possible to demostrate the complete stereospecificity of the addition of 1Δg-oxygen to the acceptor system. In this way it is shown that 1 exists in only one conformation in solution. The production of the rearranged product 23 can be explained by Hock fission from the allyl hydroperoxides 16 or 17 following the Criegee mechanism. Under the epoxidation conditions 1 is converted mainly to the two new odorous substances (–)-3-thujopsanone (4) and (–)-3-isothujopsanone (5). A series of sesquiterpenes with the thujopsane skeleton is also described, all of which have been intercorrelated.

The analysis of a coffee concentrate is described: 202 constituents have been identified, 154 of which for the first time. Some of these compounds are new chemicals; their synthesis is described. Most identifications are based upon mass spectrometry combined in many cases with IR. spectrometry and comparison with reference compounds. MS. and IR. data are given in detail. The analysis shows that a large number of minor constituents is present, many of which could not be identified.

Amino acids devoid of «leaving groups» on their β carbon atom (neither OH: serine, nor SH: cysteine) react with o-methoxycarbonyl-phenyl isothiocyanate (I) in the presence of one equivalent of NaOH, in water-dioxane or in ethanol, to yield the corresponding hydroquinazolinone derivatives II which were isolated as free acids. When treated with CH3COOH + conc. HCl the hydroquinazolinone resulting from the reaction of L-serine with I undergoes a nucleophilic attack of the carbon bearing the leaving group OH by a lone pair of electrons of S; this attack produces the formation of an additional thiazolidine ring, yielding the thiazoloquinazolinone derivative (−)-III. In an analogous reaction DL-serine phosphoric acid treated with I at pH 8–9 yields the corresponding substituted hydroquinazolinone which, boiled in 1N hydrochloric acid, undergoes ring closure to (±)-III by the same mechanism as the serine derivative (leaving group: OPO3H2). L-Cysteine reacted with 2 equiv. of I and then treated with CH3COOH + conc. HCl gives two products: (−)-III produced by the same mechanism as for serine (leaving group: SH), and the quinazolinone derivative IV where the SH group is also thiocarbamoylated.

3-Aminopropanol reacts with aryl(or aralkyl or alkyl)isothiocyanates RNCS to yield the corresponding thio-ureas RNHCSNH(CH2)3OH which, refluxed with hydrochloric acid, are cyclized by elimination of water. The cyclization products are identical with the hydrothiazines resulting by elimination of sulfate or phosphate from the sulfuric or phosphoric monoesters of these thio-ureas. The resulting hydrothiazines are either 2-(R-imino)-tetrahydro-m-thiazines (I) or 2-(R-amino)-dihydro-Δ2-m-thiazines (II). Their structure has been established by comparison of their spectra with those of model compounds in one of which the CN double bond is certainly endocyclic (2-methyl-dihydro-Δ2-m-thiazine), the other presenting an exocyclic CN double bond (3-methyl-2-phenylimino-tetrahydro-m-thiazine). When R is an aryl group, the CN double bond is exocyclic (structure I with >CNAr), and one may presume that this structure is stabilized by resonance. When R is an aralkyl or an alkyl group, the CN double bond is endocyclic (structure II). The nmr spectra were taken with three types of solvent: CDCl3 or CCl4; (CD3)2SO; CF3COOH. In CF3COOH solution the benzylic protons of the hydrothiazine with R = pFC6H4CH2 couple with NH (J=5,5cps) which confirms the endocyclic position of the CN double bond in this case.

In the presence of HCl or BF3 dihydro--ionone undergoes cyclisation. In solutions in primary alcohols ROH, this cyclisation leads to bicyclic ethers V with a semicyclic double-bond. In secondary butyl alcohol the bicyclic alcohol XII is produced. Bicyclic hydro-carbones are formed as byproducts. In benzene solution BF3 forms an unsaturated bicyclic epoxyde XVII. The infrared spectra of some of these substances are discussed.

Die Photolyse der neu untersuchten Ketone (Ib, n: 5, 6, 8) sowie der bereits untersuchten Vergleichsketone (Ib, n: 3, 4, 7) in Cyclohexan bei 15°C liefert die Alkohole (IIb) sowie die entsprechenden Cyclobutanole (III) (beide stereoisomere Formen) und die ungesättigten Ketone (IV).

Als Träger des charakterisitischen Cassis-Flavors werden die zwei Diastereomeren (I) und (II) identifiziert.

The diastereoisomeres of p-menthone-8-thiol, derived from (+)-menthol, are the first ketothiols of the terpene series to have been found in nature. Stereochemistry, methods of preparation and olfactory properties of the new compounds are described.

The photolysis of cyclic ketones from C9 to C16 has been carried out, and formation of cyclobutanols observed in only C11 to C16. Although in the mass spectrometer cyclobutanols are not formed, an initial transfer of a γ-hydrogen atom to the carbonyl group is shown to occur in the mass spectra of all cyclic ketones higher than C10.

Keto-tetrahydrothiophen (I) ergibt in Gegenwart von NaH mit Äthylacetat die beiden Acetyl-Verbindungen (II) und (III) sowie das Isomere (IV).