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Pyrimidine‐Annulated Pyrrolobenzodiazepines. A New Ring System Related to Aspergillus Alkaloids
Author(s) -
Schmidt Andreas,
Gholipour Shilabin Abbas,
Christoph Namyslo Jan,
Nieger Martin,
Hemmen Sascha
Publication year - 2005
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200400738
Subject(s) - chemistry , tautomer , azulene , ring (chemistry) , stereochemistry , pyrimidine , molecule , ab initio , crystal structure , computational chemistry , carbon 13 nmr , nuclear magnetic resonance spectroscopy , crystallography , organic chemistry
Pyrrolo[2,1‐ c ][1,4]benzodiazepine‐5,11‐dione was converted into the corresponding C‐11‐monothiolactam and subsequently treated with amines to give cyclic amidines, which racemize due to the formation of tautomers (NMR, X‐ray analysis) under basic conditions. We treated these amidines with bis(trichlorophenyl) malonate esters. Formation of neutral tautomers of the 1,3,8‐triones of the new 4,7a,12b‐triaza‐dibenzo[ e,g ]azulene ring system gave a twisted molecule with both helical and chiral structure elements (NMR, X‐ray analysis), which caused a splitting of the NMR signals into two sets. Results of two X‐ray single crystal analyses are presented, together with an ab initio calculation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)