427. The chemistry of bacteria. Part IV. A C 20-acid from violacein

Abstract

Reductive hydrolytic fission of violacein gives, in high yield, a colourless acid, CzoHlaOaNz, which on the basis of chemical and spectroscopic evidence is formulated as a y-(5-hydroxy-3-indolyl)-a-oxindolyl-y-oxobutyric acid (VII). IN earlier papers of this series it has been argued that violacein, the pigment of Chromobacterium violaceurn, contains a 5-hydroxyindole nucleus, an oxindole nucleus, and probably a hydroxypyrrole residue. The present communication is concerned with the structure of a colourless acidic degradation product, C,,H,,O,N,, obtained from violacein by the action of alkali in the presence of zinc. If, as now seems likely, the molecular formula of violacein proves to be of the type C2~-N, (see Part I11 *), then only one carbon atom and one nitrogen atom are lost in the formation of this C,,-acid, a conclusion which is consistent with the high yield of the acid and with the simultaneous production of ammonia, identified as toluene-9-sulphonamide, during the degradation.The behaviour of the C,,-acid with methylating agents showed that it is a phenolic acid containing two other weakly acidic replaceable hydrogen atoms. Thus with diazomethane the acid gave a phenolic methyl ester (a monomethyl derivative) which, rather surprisingly, was also formed by the action of methyl iodide and potassium carbonate in boiling acetone. With methyl sulphate and an excess of alkali the C,,-acid gave an acidic trimethyl derivative containing one methoxyl group, whilst the use of an excess of methyl sulphate, so that the reaction mixture finally became acidic, yielded a neutral tetramethyl derivative with two methoxyl groups. The latter compound is clearly the methyl ester of the trimethyl derivative, from which it was prepared by methyl iodide-potassium carbonate. The position of the methyl groups in the trimethyl derivative is established by the oxidation with potassium permanganate to l-methylisatin (I; R = H) and 5-methoxy-l-*

Analytical chemistry of synthetic routes to psychoactive tryptamines : Part I. Characterisation of the Speeter and Anthony synthetic route to 5-methoxy-N,N-diisopropyltryptamine using ESI-MS-MS and ESI-TOF-MS

“…Data for 2a: mp 129-131 uC (dec.), lit. : 118-119 uC, 27 123-126 uC, 28 126-127 uC, 29 127-128, 30 130 uC, 31,32 13 C NMR: (75 MHz) 180.8 (CO-b), 165.5 (CO-a), 138.3 (C q -Ph), 128.7 (C-Ph), 128.0 (C-Ph), 127.9 (C-Ph), 70.0 (OCH 2 ).…”

Investigation of Indolglyoxamide and Indolacetamide Analogues of Polyamines as Antimalarial and Antitrypanosomal Agents

“…(lit. [ 31 ] 248 °C); R f = 0.09 (20% MeOH/EtOAc); IR ν max (ATR) 3157, 2918, 1732, 1612, 1475, 1460, 1420, 1438, 1273, 1196, 1166, 913, 818, 809, 760, 709 cm −1 ; 1 H NMR (DMSO- d 6 , 400 MHz) δ H 12.29 (1H, br s, NH), 8.32 (1H, d, J = 3.4 Hz, H-2), 7.67 (1H, d, J = 2.5 Hz, H-4), 7.44 (1H, d, J = 8.8 Hz, H-7), 6.91 (1H, dd, J = 8.8, 2.5 Hz, H-6), 3.79 (3H, s, H 3 -10), OH not observed; 13 C NMR (DMSO- d 6 , 100 MHz) δ C 180.8 (C-8), 165.5 (C-9), 156.2 (C-5), 138.0 (C-2), 131.5 (C-7a), 126.6 (C-3a), 113.6 (C-7), 113.4 (C-6), 112.3 (C-3), 103.2 (C-4), 55.5 (C-10); (−)-HRESIMS m/z 218.0470 [M − H] − (calcd for C 11 H 8 NO 4 , 218.0459).…”

Physiological Aspects of Violacein Biosynthesis in Nonproliferating Cells

“…The chemical synthesis of violacein, a pigment formed by Chromobacterium violaceum, has been reported by Ballantine et al (1958). The biologically formed pigment had been previously suggested to consist of three moieties, 5-hydroxyindole, oxindole, and a 3-hydroxypyrrole (Ballantine et al, 1957a, b). The nutritional requirements and certain physiological factors involved in growth of the organism have been described (DeMoss and Happel, 1959).…”