- A Sequential Acyl Thiol-Ene and Thiolactonization Approach for the Synthesis of δ-Thiolactones
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A novel strategy for the synthesis of δ-thiolactones from inexpensive and readily available ?-unsaturated esters has been developed. This strategy incorporates a radical acyl thiol-ene reaction as the key C-S bond forming step. Cyclization is achieved via a Steglich-type thiolactonization of 5-mercaptopentanoic acids. We report the facile and scalable synthesis of δ-thiolactones in moderate to good yield under mild reaction conditions with tolerance for a range of functional groups.
- McCourt, Ruairí O.,Scanlan, Eoin M.
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p. 3460 - 3464
(2019/05/10)
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- Synthesis and biological activity of permethrinic acid analogs containing various substituents in position 2 of the cyclopropane ring
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A number of permethrinic acid ethyl ester derivatives having various substituents [Et, Pr, Ph, Ph(CH2) n (n = 1, 2), etc.] in position 2 of the cyclopropane ring were synthesized, and their insecticidal acivity against typhoid flies, rice weevils, and bean aphides, as well as juvenoid activity on flour beetle chrysalises, was studied. The newly synthesized compounds turned out to exhibit weak insecticidal activity against standard insects but pronounced juvenile hormone activity, which differentiates them from permethrinic acid esters.
- Mirzabekova,Kuz'mina,Lukashov,Sokolova,Golosov,Kazakov,Perlova,Potapova,Kheinman,Ivanova
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experimental part
p. 1139 - 1149
(2009/09/25)
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- An RCM based approach to (±)-herbertene-l, 14-diol and (±)-tochuinyl acetates
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A sequence comprising of Johnson's ortho ester Claisen rearrangement, alkylation and RCM reactions has been developed for the synthesis of cyclopentenes containing vicinal quaternary carbon atoms. The versatility of the sequence has been demonstrated by the efficient total synthesis of sesquiterpenes tochuinyl acetates and herbertene-1,14-diol.
- Srikrishna,Rao, M Sreenivasa
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p. 1308 - 1317
(2008/09/18)
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- Lithium-liquid ammonia mediated carbocyclisation of δ,ε- unsaturated esters: Annulation of cyclopentanones
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Lithium-liquid ammonia mediated carbanion cyclisation of δ,ε-unsaturated esters leading to cyclopentanes, fused as well as spiro, via annulation is described.
- Srikrishna,Ramasastry
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p. 379 - 382
(2007/10/03)
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- A simple, ring-closing metathesis reaction based approach to (±)-1,14-herbertenediol and (±)-11-epi-herbertenolide
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A total synthesis of 1,14-herbertenediol via 11-epi-herbertenolide, and a formal total synthesis of tochuinyl acetate and dihydrotochuinyl acetate, employing a ring-closing metathesis reaction based methodology, are described.
- Srikrishna,Rao, M.Srinivasa
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p. 151 - 154
(2007/10/03)
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- Application of Microwave Heating Technique for Rapid Synthesis of γ,δ-Unsaturated Esters
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The use of microwave heating technique for the acceleration of ortho ester Claisen rearrangement (a three step transformation) is described.Irradiation of a DMF solution of the allyl alcohol 5, triethyl orthoacetate and propionic acid (catalytic) in an Erlenmeyer flask for 10 minutes in a microwave oven generated the ester 8 in 83percent yield.Analogously, ortho ester Claisen rearrangement of a variety of allyl and propargyl alcohols (9, 12-22) were achieved.The formation of the diester 10 from 2-butyne-1,4-diol (9) via the ortho ester Claisen rearrangement of two allyl alcohol moieties (involving six steps) in 15 minutes, demonstrates the versatility of the microwave heating technique.
- Srikrishna, Adusumilli,Nagaraju, Sankuratri,Kondaiah, Paturu
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p. 1809 - 1816
(2007/10/02)
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- Acceleration of Ortho Ester Claisen Rearrangement by a Commercial Microwave Oven
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Microwave irradiation, using a commercial microwave oven accelerates (in 10-15 min) the three-step ortho ester Claisen rearrangement of allyl and propynyl alcohols in dry DMF in open Erlenmeyer flasks.
- Srikrishna, Adusumilli,Nagaraju, Sankuratri
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p. 311 - 312
(2007/10/02)
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