- Efficient solid-phase synthesis of highly functionalized 1,4-benzodiazepin-5-one derivatives and related compounds by intramolecular aza-wittig reactions
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Due to their widespread biological activities and favorable pharmacokinetic properties, benzodiazepines were among the first classes of small molecules to be synthesized on solid supports. Since then, there have been numerous reports on the synthesis of similar skeletons. We have employed the T1 triazene linker to yield 1,4-benzodiazepin-5-one. Starting from various substituted triazene resins, cleavage in the presence of an azide donor, such as trimethylsilylazide, gave rise to aryl azides. Intramolecular aza-Wittig reactions produced the appropriately functionalized N-heterocycles. By using this route, the natural product deoxyvasicinone and related compounds were prepared.
- Gil, Carmen,Braese, Stefan
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- A polymer-assisted solution-phase strategy for the synthesis of fused [2,1-b]quinazolinones and the preparation of optically active vasicinone
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An efficient preparation of fused [2,1-b]quinazolinones has been developed utilizing polymer-supported reagents. (±)- Vasicinone was converted into its dione by oxidation with poly (4-vinylpyridiniumdichromate). An efficient method has been developed for the synthesis of (d)- and (l)-vasicinone via asymmetric reduction of pyrrolo[2,1-b]quinazoline-3,9-dione by employing NaBH4/Me3SiCl as the reducing agent and polymer-supported chiral sulfonamide as catalyst. Georg Thieme Verlag Stuttgart.
- Kamal, Ahmed,Devaiah,Shankaraiah,Laxma Reddy
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p. 2609 - 2612
(2008/09/16)
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- One pot conversion of azido arenes to N-arylacetamides and N-arylformamides: Synthesis of 1,4-benzodiazepine-2,5-diones and fused [2,1-b]quinazolinones
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Sodium iodide in acidic media has been employed for the synthesis of N-arylformamides and N-arylacetamides. The NaI/acetic acid reagent system has also been extended for the synthesis of 1,4-benzodiazepine-2,5-diones, pyrrolo[2,1-c][1,4]benzodiazepine-5,11-diones, and fused [2,1-b]quinazolinones.
- Kamal, Ahmed,Ramana, A. Venkata,Reddy, K. Srinivasa,Ramana, K. Venkata,Hari Babu,Prasad, B. Rajendra
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p. 8187 - 8190
(2007/10/03)
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- Chemoenzymatic synthesis of pyrrolo[2,1-b]quinazolinones: Lipase-catalyzed resolution of vasicinone
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A facile synthesis of bronchodilatory pyrrolo[2,1-b]quinazoline alkaloids by azidoreductive cyclization strategy employing TMSCl-NaI and bakers' yeast is described. Both the chemical and enzymatic methods are mild and take place at room temperature in good yields. Further, synthesis and resolution of vasicinone has been carried out by employing different lipases. It has been observed that lipase PS provides acetate of (S)-vasicinone in 98% ee.
- Kamal,Ramana,Rao
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p. 997 - 1001
(2007/10/03)
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- Novel Ring Enlargement of Lactams via Quinazolinone Annelation. A Facile Route to Benzoannelated Large-Membered Cyclic 1,5-Diamines
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A novel route to benzoannelated large-membered cyclic 1,5-diamines from lactams is described.Thus, n-membered lactames 1 were N-acylated by o-azidobenzoyl chloride 5 to afford the corresponding imides 4.These were treated with tributylphosphine and underw
- Takeuchi, Hisato,Matsushita, Yuji,Eguchi, Shoji
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p. 1535 - 1537
(2007/10/02)
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