Tetrahydro-jS-carbolines

Treatment of tetrahydro-/J-carboline 7 with solid potassium permanganate provides imine 8.11,12 The ethyl ester group is stable under these conditions in contrast to the methyl ester 22. 

The characteristic tetrahydro-/ -carboline fragments of mass 156, 169, 170, and 184 are partly shifted if a further ring is fused on at the 5 position, e.g., in akuammidine (204). Alkaloids of this skeleton show the tetrahydro-/J-carboline fragments at mass 156, 168, 169, and 182.92.97 Usually the bridge is lost very easily.92,97-99 The most attractive mechanism for this reaction, in which a hydrogen shift is involved, seems to lead, through the cleavage of the bond between C-5 and C-16, to an intermediate [205], which may decompose further... 

B. Rbnner, H. Lerche, W. Bergmuller, C. Freilinger, T. Severin, and M. Pischetsrieder, Formation of tetrahydro-(J-carbolines and 3-carbolines during the reaction of L-tryptophan with o-glucose, J. Agric. Food Chem., 48 (2000) 2111-2116. 

S-Carboline alkaloids possess the tricyclic ring system shown in the formula below. Often the 6-membered nitrogen-containing ring is hydrogenated (1,2,3,4-tetrahydro-j -carbolines). Most alkaloids carry substituents in position 3. Additional rings may be present (cf. the formulas of the iridoid carbolines in Fig. 259). 

A suspension of l-(4-benzyloxy-3-methoxybenzyl)-l,2,3,4-tetrahydro-) -carboline hydrochloride and 5%-Pd-on-carbon in 50%-ethanol hydrogenated 1 hr. at 60°/ 1.7 atm. 1-(4-hydroxy-3-methoxybenzyl)-1,2,3,4-tetrahydro-j -carboline hydro-... 

Han, QP and Dryhurst, G (1996) Influence of glutathione on the oxidation of l-methyl-6-hydroxy-l,2,3,4-tetrahydro-beta-carboline chemistry of potential relevance to the addictive and neurodegenerative consequences of ethanol use. J. Med. Chem. 39 1494-1508. 

N. Ide, M. Ichikawa, K. Ryu, K. Ogasawara, J. Yoshida, S. Yoshida, T. Sasaoka, S.-I. Sumi, and H. Sumiyoshi, Antioxidants in processed garlic. II. Tetrahydro-b-carboline derivatives identified in aged garlic extract, in G, 2002, 449 150. 

Herraiz, X, Huang, Z.X. Ough, C.S. (1993). l,2,3,4-Tetrahydro-beta-carboline-3-carboxylic acid and 1-methyl-1,2,3,4- tetrahydro-beta carboline-3-carboxylic acid in wines. J. Agric. Food Chem., 41, 455-459. 

Adachi J, Asano M, and Ueno Y (2000) Tetrahydro-beta-carboline-3-carboxylic acids and contaminants on L-try-ptophan. Journal of Chromatography A 881 501-515. 

The factors that control diastereoselection in the construction of 1,3-disubstituted tetrahydro- 3-car-bolines are not, as yet, well understood. With many aldehydes a slight preference for forming the trans diastereomer is observed.34 This preference is somewhat greater when the indole nitrogen (Na) of the tryptamine is alkylated. Pictet-Spengler cyclizations of Mrbenzyltryptophan methyl ester under Cook s aprotic conditions are reported to provide nearly exclusively the fr[Pg.1017]

Adachi, J., Mizoi, Y., Naito, T., Ogawa, Y., Uetani, Y. and Ninomiya, I. (1991a) Identification of tetrahydro-beta-carboline-3-carboxylic acid in foodstuffs, human urine and human milk. J. Nutr. 121 646-652. 

Matsubara, K., Collins, M.A. and Neafsey, E.J. (1992a) Mono-A-methylation of 1,2,3,4-tetrahydro-beta-carbolines in brain cytosol absence of indole methylation. J. Neuro-chem. 59 505-510. 

Gander, J.E. etal 1976. The occurrence of 2-methyl-i,2,3,4-tetrahydro-P-carboline and variation in alkaloids in Phalaris ar-undinacea" Phytochemistry 15 737—738. 

The failure of AT-acetyltryptamine to act as a precursor for the tetrahydro- -carboline alkaloid eleagnine (54), in contrast to its successful incorporation into the j -carboline harman (53), has led to the suggestion that they may arise by different routes." This is supported by the successful isolation by radioisotope dilution of iV-acetyltryptamine from P. edulis, " but failure under similar conditions to detect it in E. angustifolia. In contrast, however, eleagnine (54) and harmalan (59) are efficiently and specifically incorporated into harman in P. 

Another approach to this enantioselective cyclization involves the formation of imines from N-)S-(3-indolyl)ethyl amino acid esters and a variety of aryl aldehydes. These imines give tetrahydro-)S-carbolines with diastereomer ratios of up to 98.5 1.5 (Scheme 27) <94T11865>. The chiral auxilliary group can be removed after cyclisation. The iminophosphorane (103), derived from a dehydrotryptophan, reacts thermally with aldehydes to give the /J-carbolines (104) (Equation (28)) <92TL289i>. In contrast, the dehydrotryptophan (105) itself interacts with aldehydes to form compounds (106) with the clavicipitic acid skeleton (Scheme 28) <86TL4757>. 

Kuehne ME, Roland DM et al (1978) Studies in biomimetic alkaloid syntheses. 2. Synthesis of vincadifformine from tetrahydro-b-carboline through a secodine intermediate. J Org... 

Fig. 19.1 Structure of some P-carbolines synthesized biologically and chemically (1) Prom plant (a, b, c, d, e, f, and g) (2) Prom animals (a, d, g,h, i, j, and k) (3) Synthesized chanically (1 and m). (a) Harman (b) harmaline (c) harmine (d) norharman (e) hatmol (f) harmalol (g) tetrahydrohatmine (h) tryptoline (i) pinoline (j) l-(2-guanidinoethyl)-l,2,3,4-tetrahydro-6-hydroxymethyl)-P-carboline [37] (k) manzamine A [39] (1) 3-ethyl-l-phenyM,9-dihydro-3//-beta-carbolme (m) lV-butyl-1-(4-dimethylammo)phenyl-l,2,3,4-tetrahydro-P-carboline-3-carboxamide [40]...

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