Acid-catalysed epimerization of indolo[2,3-a]quinolizidine derivatives:: Role of the nitrogen lone pairs in the mechanism

被引：20

作者：

Lounasmaa, M ^{[1
]}

Berner, M ^{[1
]}

Brunner, M ^{[1
]}

Suomalainen, H ^{[1
]}

Tolvanen, A ^{[1
]}

机构：

[1] Tech Univ Helsinki, Organ & Bioorgan Chem Lab, HUT-02015 Espoo, Finland

来源：

TETRAHEDRON | 1998年 / 54卷 / 34期

关键词：

D O I：

10.1016/S0040-4020(98)00614-0

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The role of the nitrogen lone pairs in the mechanism of the acid-catalysed epimerization of indolo[2,3-a]quinolizidines is investigated using lactams as model compounds. Deethyleburnamonine (3) did not epimerize with trifluoroacetic acid (TFA), whereas deethyldihydroebumamenine (7) underwent epimerization smoothly. Under treatment with TFA, lactams 12 and 13 both epimerized with ease to a mixture of lactams 12 and 13. An analogous equilibrium was achieved when the experiment was repeated with lactams 18 and 19. Intermediate 20 was trapped (Zn reduction) in the acid-catalysed epimerization of lactam 12, allowing conclusions about the mechanism. (C) 1998 Elsevier Science Ltd. All rights reserved.

引用

页码：10205 / 10216

页数：12

共 21 条

[1] THE ALKALOIDS OF HUNTERIA-EBURNEA .1. THE STRUCTURES OF EBURNAMINE, ISOBURNAMINE, EBURNAMENINE AND EBURNAMONINE AND A SYNTHESIS OF RAC-EBURNAMONINE [J].

BARTLETT, MF ;

TAYLOR, WI .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1960, 82 (22) :5941-5946

[2] REACTIONS WITH INDOLE-DERIVATIVES .25. STEREOSELECTIVE TOTAL SYNTHESIS OF ROXBURGHIN-D [J].

BENZ, G ;

RIESNER, H ;

WINTERFELDT, E .

CHEMISCHE BERICHTE-RECUEIL, 1975, 108 (01) :248-259

[3]

BOHLMANN C, 1985, LIEBIGS ANN CHEM, P1752

[4]

CAREY FA, 1990, ADV ORGANIC CHEM A, P474

[5] Evidence for C(1)-N(2) bond scission in the isomerization of cis-1,3-disubstituted N-b-benzyl-1,2,3,4-tetrahydro-beta-carbolines into their trans diastereomers under acidic conditions [J].

Cox, ED ;

Li, J ;

Hamaker, LK ;

Yu, P ;

Cook, JM .

CHEMICAL COMMUNICATIONS, 1996, (21) :2477-2478

[6] Enantiospecific formation of trans 1,3-disubstituted tetrahydro-beta-carbolines by the Pictet-Spengler reaction and conversion of cis diastereomers into their trans counterparts by scission of the C-1/N-2 bond [J].

Cox, ED ;

Hamaker, LK ;

Li, J ;

Yu, P ;

Czerwinski, KM ;

Deng, L ;

Bennett, DW ;

Cook, JM ;

Watson, WH ;

Krawiec, M .

JOURNAL OF ORGANIC CHEMISTRY, 1997, 62 (01) :44-61

[7] ZINC-ACETIC ACID REDUCTION OF RESERPINE AND OTHER TETRAHYDRO-BETA-CARBOLINE ALKALOIDS [J].

GASKELL, AJ ;

JOULE, JA .

TETRAHEDRON, 1968, 24 (14) :5115-&

[8] ACID CATALYSED C3 EPIMERIZATION OF RESERPINE AND DESERPIDINE [J].

GASKELL, AJ ;

JOULE, JA .

TETRAHEDRON, 1967, 23 (10) :4053-&

[9]

GOOTJES J, 1965, RECL TRAV CHIM PAY-B, V84, P1183

[10] ALPHA-METHYLENELACTAM REARRANGEMENT [J].

LEE, DL ;

MORROW, CJ ;

RAPOPORT, H .

JOURNAL OF ORGANIC CHEMISTRY, 1974, 39 (07) :893-902

← 1 2 3 →