608141-08-8Relevant academic research and scientific papers
1,3-benzyl migration in iminium ions: Evidence for a fast free-radical chain reaction
Blank, Nancy,Straub, Bernd F.,Opatz, Till
experimental part, p. 7355 - 7365 (2012/01/06)
The "exocyclic" 1,3-benzyl shift observed in iminium salts derived from 1-benzyl-1,2,3,4-tetrahydroisoquinolines is related to the "endocyclic" Knabe rearrangement. A crossover experiment, isotopic labelling, the study of initiators and inhibitors as well as DFT calculations of gas-phase model structures provide evidence for a free-radical pathway under kinetic entropy control that is not affected by "slow" radical traps. An unexpected rearrangement of methyleneiminium ions derived from 1-benzyl-1,2,3,4-tetrahydroisoquinolines has been investigated by isotopic labelling, trapping experiments and DFT calculations. Theobserved benzyl migration proceeds by an exceptionally fast radical chain reaction closely related to the Knabe reaction.Remarkably, the process is inhibited byneither methyl acrylate nor dioxygen. Copyright
Enantioselective synthesis of tetrahydroprotoberberines and bisbenzylisoquinoline alkaloids from a deprotonated α-aminonitrile
Blank, Nancy,Opatz, Till
experimental part, p. 9777 - 9784 (2012/01/30)
Under controlled conditions, 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline- 1-carbonitrile can be quantitatively deprotonated in the α-position. Its alkylation directly furnishes 3,4-dihydroisoquinolines which can serve as starting materials for the preparation of various alkaloids. Here, the preparation of the benzylisoquinolines (+)-laudanidine, (+)-armepavine, and (+)-laudanosine as well as the tetrahydroprotoberberines ( - )-corytenchine and ( - )-tetrahydropseudoepiberberine using Noyori's asymmetric transfer hydrogenation are described. The dimeric alkaloids (+)-O-methylthalibrine and (+)-tetramethylmagnolamine were obtained from nonracemic precursors in Ullmann diaryl ether syntheses.
Oxidation of 1-benzyldihydroisoquinolines or 1- benzyltetrahydroisoquinolines with dioxygen to 1-benzoylisoquinolines
Gan, Haifeng,Lu, Yunyu,Huang, Yue,Ni, Lijun,Xu, Jinyi,Yao, Hequan,Wu, Xiaoming
scheme or table, p. 1320 - 1324 (2011/04/15)
An environmental-benign methodology to synthesize 1-benzoylisoquinolines from 1-benzyl-3, 4-dihydroisoquinolines or 1-benzyl-1,2,3,4- tetrahydroisoquinolines using dioxygen as an oxidant was developed. This methodology in combination with Bischler-Napieralski reaction leads to a facile synthesis of 1-benzoylisoquinolines from phenylacetic acids and phenylethanamines.
Synthesis of (±)-Glaucine and (±)-Neospirodienone via an One-Pot Bischler-Napieralski Reaction and Oxidative Coupling by a Hypervalent Iodine Reagent
Huang, Wei-Jan,Singh, Om V.,Chen, Chung-Hsiung,Lee, Shoei-Sheng
, p. 167 - 174 (2007/10/03)
Condensation of 3,4-dimethoxybenzeneethanamine (3d) and various benzeneacetic acids, i.e., 4a-e, via a practical and efficient one-pot Bischler-Napieralski reaction, followed by NaBH4 reduction, produced a series of 1-benzyl-1,2,3,4-tetrahydroisoquinolines, i.e., 5a-e, in satisfactory yields (Scheme 3). Oxidative coupling of the N-acyl and N-methyl derivatives 6a-e of the latter with hypervalent iodine ([IPh(CF 3COO)2]) yielded products with two different skeletons (Scheme 4). The major products from N-acyl derivatives 6a-c were (±)-N-acylneospirodienones 2a-c, while the minor was the 3,4-dihydroisoquinoline 7. (±)-Glaucine (1), however, was the major product starting from N-methyl derivative 6e. Possible reaction mechanisms for the formation of these two types of skeleton are proposed (Scheme 5).
Antiplatelet activity of synthetic pyrrolo-benzylisoquinolines
Kuo, Reen-Yen,Wu, Chin-Chung,Chang, Fang-Rong,Yeh, Jwu-Lai,Chen, Ing-Jun,Wu, Yang-Chang
, p. 821 - 823 (2007/10/03)
Pyrrolo-benzylisoquinolines were prepared as target compounds and their antiplatelet aggregation activity, adreno-receptor affinity, and cytotoxicity were screened. Compounds 1d-9d showed specific antiplatelet aggregation activity induced by arachidonic acid and collagen. Among them, 8d and 9d exhibited better activity than the reference drug, aspirin and 9d also showed inhibition of platelet aggregation by all four inducers.
