Application of Nazarov type electrocyclization to access [6,5,6] and [6,5,5] core embedded new polycycles: an easy entry to tetrahydrofluorene scaffolds related to Taiwaniaquinoids and C-nor-D homosteroids
Application of Nazarov cyclization to access [6-5-6] and [6-5-5]tricyclic core embedded new heterocycles: an easy entry to structures related to Taiwaniaquinoids
作者:Ritesh Singh、Maloy Kumar Parai、Gautam Panda
DOI:10.1039/b901632e
日期:——
A concise and general route to synthesize a new class of [6-5-6] tricyclic core embedded polyheterocycles has been accomplished using diastereoselective Nazarov cyclization with an overall yield of 35–40%. Versatility of this synthetic route has also been demonstrated by accessing a variety of [6-5-5] tricyclic core incorporated polycycles. It was observed that the efficiency of cyclization depends
Reactions of some 2H-Chromenes and 2H-Thiochromenes with triazolinediones
作者:Christopher D. Gabbutt、John D. Hepworth、B. Mark Heron
DOI:10.1016/0040-4020(95)00874-8
日期:1995.11
Simple 2H-chromenes and 2H-thiochromenes form the [2+2]-adducts, tetrahydro[1]benzo(thio)pyrano[3,4-c] [1,2]diazeto[1,2-a][1,2,4]triazoles, with triazolinediones, whereas their 3- and 4-bromo and the corresponding cycloalkylamino derivatives undergo an overall etectrophilic substitution sequence.
Gabbutt, Christopher D.; Hepworth, John D.; Heron, B. Mark, Journal of the Chemical Society. Perkin transactions I, 1994, # 6, p. 653 - 658
作者:Gabbutt, Christopher D.、Hepworth, John D.、Heron, B. Mark
DOI:——
日期:——
An unexpected reaction of phosphorous tribromide on chromanone, thiochromanone, 3,4-dihydro-2H-benzo[b]thiepin-5-one, 3,4-dihydro-2H-benzo[b]oxepin-5-one and tetralone derived allylic alcohols: a case study
作者:Maloy K. Parai、Shagufta、Ajay K. Srivastava、Matthias Kassack、Gautam Panda
DOI:10.1016/j.tet.2008.07.106
日期:2008.10
Treatment of chromanone, thiochromanone, tetralone and benzo[b]thiepinone derived allylic alcohols with phosphorous tribromide furnished unexpected products instead of desired bromo derivatives. Reaction of 7-methoxy-2,2-dimethylchromenyl-aryl-methanols and 7-methoxy-2,2-dimethylthio-chromenyl-aryl-methanols with PBr3 gave saturated carbonyls and exocyclic olefins depending on the substituents at R-4, whereas allylic alcohols without 7-methoxy substituent furnished rearranged products. Several related analogs varying in ring size, heteroatom in the ring and substituents at various positions were synthesized and studied. Reactions of other phosphorous-based reagents like PPh3, PPh3/I-2 and PPh3Br2 on allylic alcohols were also attempted. A case study is presented here. (C) 2008 Elsevier Ltd. All rights reserved.
Gabbutt Christopher D., Hartley David J., Hepworth John D., Heron B. Mark+, Tetrahedron, 50 (1994) N 8, S 2507- 2522
作者:Gabbutt Christopher D., Hartley David J., Hepworth John D., Heron B. Mark+