Investigation of the coupling reaction of tetraacetylsecologanin with oxotryptamine and its derivative

Patthy-Lukats, A Beke, G Szabo, LF Podanyi, B

A. Patthy-lukats et al., Investigation of the coupling reaction of tetraacetylsecologanin with oxotryptamine and its derivative, J NAT PROD, 64(8), 2001, pp. 1032-1039

29

INGLESE

Article

Agricultural Chemistry","Pharmacology & Toxicology

JOURNAL OF NATURAL PRODUCTS

0163-3864 → ACNP

64

8

2001

1032 - 1039

ISI

0163-3864(200108)64:8<1032:IOTCRO>2.0.ZU;2-4

The coupling reaction of tetraacetylsecologanin with 2,3-dihydro-2-oxotrypt amine and its N-b-benzyl derivative was investigated. With the benzylated a mine, the reaction was stopped at the tetracyclic ester level, and with the unsubstituted amine it was immediately followed by lactamization. In both cases, the products were formed with high stereoselectivity at C-3, but as an epimeric pair of 7R and 7S in a ratio of 1:3. The bulky benzyl substitue nt at N-4 directed the stereoselectivity at C-3 in favor of the S configura tion. In the nonbenzylated compounds, the reversible coupling reaction is p robably nonstereoselective, but in lactamization the 3R epimer is stericall y favored and faster and gives the final lactam in this configuration. The formation of the spiro compounds may serve as a model reaction in the inter pretation of the stereoselectivity of the coupling reaction of secologanin with tryptamine in the presence of strictosidine synthase.