The Course of the Willgerodt‐Kindler Reaction of Alkyl Aryl Ketones

Abstract

Fig. 12. log k VA. A pK Dependence for base-catalysed decomposition of nitramide at 15 "C (Bronsted and Pedersen [go]. Catalytically active base = Y (conjugate acid HY). The broken iines denote the extrapolated curves with a and P = 0 ar I . Upper curve: diffusion-controlled limiting value. Ordinate: log k. Abscissa: p K~y .sen for the tautomerization equilibrium of nitramide which precedes decomposition. If the rate constant is based on the concentration of the reactive form, then extrapolation to cc = 0 affords exactly the limiting value for diffusion-controlled reactions.In other systems, such as mutarotation of glucose [93], dehydration of acetaldehyde hydrate [94], constancy of the values of CI is observed over a relatively wide pK range. As expected in these cases, k is relatively small over the entire range. Here, the rate-determining step is not a simple proton transfer but the coupling of several intermediate steps. Such events are particularly important with regard to enzymic processes. They will be the main subject of the discussion presented in Part 11.Ketones react with sulfur and NH3 or amines at room temperature to produce A3-thiazolines, 5-alkylidene-A3-thiazolines, A3-imidazoline-5-thiones, hexathiacycloheptane derivatives, u,u'-dioxodisulfideJideS, bis-(I-aralk-I-yl) disulfides, or thiocarboxamides, depending on the coreactant and on the reaction conditions. It was recognized that the formation of all of these numerous types of compounds can be explained basically by primary thiolations and geminal dithio lations, which in conjunction with their reverse reaction (desulfurization) and the assumption of a thioreductone equilibrium permit a new interpretation of the course of the Willgerodt-Kindler reaction of alkyl aryl ketones.Received, September 9th, 1963 [A 336/135 IE] German version: Angew.Lysozymes are widely distributed enzymes. They split the chemical skeleton of bacterial cell walls by hydrolysing the p ( I + 4 ) linkages between N-acetylmuramic acid and N-acetylglucosamine. The amino acid sequence of lysozyme from hen's egg-white is known (129 amino acid residues). Lysozymes of different origins frequently differ in their primary structures although they exhibit qualitatively the same biological activity. The results obtained from investigations with lysozymes allow conclusions to be drawn regarding the chemical structure of the "backbone" of bacterial cell walls.

Reactions of Benzylamine with Sulfur

“…Case (i) Following decomposition according to [6], the reaction of (3a -b) sulfurs with 4 benzylamines according to [13] must be considered. For the values of a, b, and x relevant to this case (a = 2 since the starting material is the disulfide, b --4 and x = 6-7), it is apparent that 3a -b < a + x.…”

“…Therefore, reaction 13 is limited by the quantity of sulfur present and not by the quantity of benzylamine. Multiplying [13] by (3a -b)/(a + x) and adding this result to [6] eliminates the sulfur and leads to [24].…”

“…Before deriving these predic2Frorn the charge balance it is apparent that (8 -a ) / x must equal 1 in this particular equation (i.e., a + x = 8). [13]. Second, since benzyl- absence of benzylamine (alternatively and equally good, equilibrium [7] may lie fairly far to theleft).…”

“…Finally, it should be noted that eliminated by adding eq. 6 to three times [13] to the benzylamine polysulfides formed in [7] have give [17]. The benzylidenimine polysulfides may …”

“…Most of the proposed mechanisms (1,2,9,(13)(14)(15)(16)(17) have considered the first step to be attack either by the amine at the carbonyl carbon or by sulfur at the u-carbon to the carbonyl group. This step is generally thought ried out in the presence of a hydrogen sulfide scavenger (25,27).…”