TAILIEUCHUNG - The isomerization of cis-benzo[a]furo[2,3-g]quinolizin to its trans isomer in acetic acid

Two stereoisomers of benzo[a]furo[2,3-g]quinolizine derivatives were obtained by alkylation of stereoisomeric 7a-methyl-2-oxo-5-phenylfuro[2,3-c]piperidines with methallyl chloride and subsequent cyclization of alkylated products in the mixture of trifluoroacetic and concentrated sulphuric acids. It is interesting to find that the cis-quinolizine, upon heating to 150o C in glacial acetic acid, is isomerized to the trans-isomer. | Journal of Chemistry Vol. 45 Special issue P. 150 -153 2007 THE ISOMERIZATION OF C S-BENZO A FURO 2 3-G QUINOLIZINE TO ITS TRANS ISOMER IN ACETIC ACID Received 18 December 2007 VU DINH HOANG Department of Organic Chemistry Hanoi University of Technology SUMMARY Two stereoisomers of benzo a furo 2 3-g quinolizine derivatives were obtained by alkylation of stereoisomeric 7 a-methyl-2-oxo-5-phenylfuro 2 3-c piperidines with methallyl chloride and subsequent cyclization of alkylated products in the mixture of trifluoroacetic and concentrated sulphuric acids. It is interesting to find that the cis-quinolizine upon heating to 150oC in glacial acetic acid is isomerized to the trans-isomer. I - INTRODUCTION Chemistry of benzo a quinolizines is of great interest because of their structural similarity to natural and synthetic biologically active compounds 1 . Previously it was shown that N- P-hydroxyethyl and N-allyl substituted 2-oxofuro 2 3-c piperidines can be converted to benzo a furo 2 3-g quinolizines through intramolecular cyclization possesing psychotropic activity and proposing certain interest for the synthesis of new biologically active compounds 2 . In this work two stereoisomers of benzo a furo 2 3-g quinolizine were prepared and the cis-isomer was shown to be transformed to the thermodynamically more stable transisomer. II - EXPERIMENTAL IR spectra of solutions of all the compounds in CCl4 were recorded in Specord IR-75 instrument. 1H-NMR spectra in CDCl3 were obtained in a Brucker WM-360 instrument with HMDS as internal standard. The course of reactions and the purity of products were monitored by TLC on Silufol plates with 2 1 ether-hexane as the eluent. The 2-oxofuro 2 3-c piperidines 1 2 were prepared in accordance 150 with 3 . Elemental analyses for C H and N were consistent with the calculated contents table 1 . 7a-methyl-6- 2-methyl-2-propenyl -2-oxo-5-phenylfuro 2 3-c piperidine 3 4. g mole of lactone 1 2 ml mole of .

• Hoá học
• Công nghệ hóa
• Isomerization of cis benzo[a]furo[2
• 3 g]quinolizin
• Trans isomer
• Acetic acid
• Hóa hữu cơ
• Kỹ thuật hệ thống công nghệ hóa học
• Hệ thống công nghệ hóa học
• Công nghệ hóa học
• Tối ưu hóa
• Quá trình công nghệ hóa học
• Phương pháp giải thích
• Quy hoạch toán học
• Phương pháp gradient
• Mô hình hóa công nghệ hóa học
• Nghiên cứu công nghệ hóa học
• Mô tả công nghệ hóa học
• giáo trình công nghệ hóa học
• thiết bị công nghệ hóa học
• bài giảng công nghệ hóa học
• công nghệ hóa chất
• tài liệu công nghệ hóa chất
• áp dụng công nghệ hóa chất
• tìm hiểu công nghệ hóa chất
• nghiên cứu công nghệ hóa chất
• công nghệ hóa dầu
• bài giảng công nghệ hóa dầu
• giáo trình công nghệ hóa dầu
• tài liệu công nghệ hóa dầu
• lý thuyết công nghệ hóa dầu