Synthesis of (+/-)-nitramine and (+/-)-isonitramine by utilizing stereoselective reduction of ethyl 1-(3-bromopropyl)-2-oxocyclohexanecarboxylate

Formal synthesis of (+/-)-nitramine (1) and (+/-)-isonitramine (2) was achieved. Thus, the reduction of ethyl 1-(3-bromopropyl)-2-oxocyclohexanecarboxylate (6) with NaBH4 in MeOH gave the corresponding cyclohexanol (7) having cis geometry between hydroxyl and ester groups, predominantly. On the othe...

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Bibliographic Details
Published inHeterocycles Vol. 46; pp. 413 - 420
Main Authors Senboku, H, Hatazawa, M, Orito, K, Tokuda, M
Format Journal Article
LanguageEnglish
Published OXFORD Elsevier 1997
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
BIOMIMETIC SYNTHESIS
ENANTIOSELECTIVE TOTAL SYNTHESIS
BETA-KETOESTERS
NITRARIA ALKALOIDS
(+)-ISONITRAMINE
(+/-)-SIBIRINE
NITRAMINE
SPIROCYCLIC ALKALOIDS
(+)-NITRAMINE
ISONITRAMINE
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Summary:Formal synthesis of (+/-)-nitramine (1) and (+/-)-isonitramine (2) was achieved. Thus, the reduction of ethyl 1-(3-bromopropyl)-2-oxocyclohexanecarboxylate (6) with NaBH4 in MeOH gave the corresponding cyclohexanol (7) having cis geometry between hydroxyl and ester groups, predominantly. On the other hand, the trans located isomer (8) was preferentially obtained by reduction with LiAl(OBu')(3)H in THF. Treatment of the former reduction product (7) having cis geometry with benzylamine at 60 degrees C gave cis located ethyl 1-(3-(N-benzylamino)-propyl)-2-hydroxycyclohexanecarboxylate (9), which was further treated with BuLi to give a spirolactam, 2-benzyl-7-hydroxy-2-azaspiro[5,5]undecan-1-one (11) in 84% yield. Reduction of the lactam (11) with BH3 . SMe2 in THF gave N-benzylnitramine (13). In a similar manner, N-benzylisonitramine (14) was synthesized from trans located hydroxyaminoester (10).
ISSN:0385-5414
DOI:10.3987/com-97-s40