A Novel Synthetic Method of the (±)-(3aα,8aα)-Ethyl 8β-Hydroxy-6β-methyl-2-oxooctahydro-2H-cyclohepta[b]furan-3α- carboxylate and Its Chemical Transformation to (±)-(3aα,8aα)-3α,6β-Dimethyl-3,3a,4,5,6,8a-hexahydro-2H- cyclohepta[b]furan-2-one, (+)- and (−)-7β-(2-Acetoxy-1α-methylethyl)-4β-methyl-2-cyclohepten-1β-ol, and (+)- and (−)-7β-(2-Acetoxy-1α-methylethyl)-4β-methyl-2-cyclohepten-1-one. Possible Common Synthetic Intermediates for Pseudoguaianolides, 4,5-Secopseudoguaianoli

Shimoma, Fumito; Kusaka, Haruhiko; Wada, Katsuhiko T.; Azami, Hidenori; Yasunami, Michio; Suzuki, Toshio; Hagiwara, Hisahiro; Ando, Masayoshi

doi:10.1021/jo971529q

Cited by 32 publications

(7 citation statements)

References 34 publications

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“…Selective synthesis of 2 H -cyclohepta[ b ]furan-2-ones 26 and 27 with an alkyl function at the 6-position starting from hinokitiol 21a [ 28 ] or 4-methyltropolone 21b [ 29 ] was established by a four-step procedure ( Scheme 7 ). This is because direct tosylation of 21a and 21b produces an inseparable mixture of 22a , b and 23a , b due to inherent tautomerism, and besides, these are difficult to separate.…”

Section: Synthetic Methods Of 2 H -Cyclohepta[ B ]Furan-2-onesmentioning

confidence: 99%

“…[26] The reaction of 2,5dichlorotropone 19 derived from 5-chlorotropolone with dimethyl malonate yields 5-chloro-2H-cyclohepta[b]furan-2-one 13e, which can also be converted to 20 via decarboxylation in a similar manner as described above (Scheme 6) [27]. Selective synthesis of 2H-cyclohepta[b]furan-2-ones 26 and 27 with an alkyl function at the 6-position starting from hinokitiol 21a [28] or 4-methyltropolone 21b [29] was established by a four-step procedure (Scheme 7). This is because direct tosylation of 21a and 21b produces an inseparable mixture of 22a,b and 23a,b due to inherent tautomerism, and besides, these are difficult to separate.…”

Section: Synthetic Methods Of 2h-cyclohepta[b]furan-2-onesmentioning

confidence: 99%

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Synthesis of Azulene Derivatives from 2H-Cyclohepta[b]furan-2-ones as Starting Materials: Their Reactivity and Properties

Shoji

Ito

Yasunami

2021

IJMS

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A variety of synthetic methods have been developed for azulene derivatives due to their potential applications in pharmaceuticals and organic materials. Particularly, 2H-cyclohepta[b]furan-2-one and its derivatives have been frequently used as promising precursors for the synthesis of azulenes. In this review, we describe the development of the synthesis of azulenes by the reaction of 2H-cyclohepta[b]furan-2-ones with olefins, active methylenes, enamines, and silyl enol ethers as well as their reactivity and properties.

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Section: Synthetic Methods Of 2 H -Cyclohepta[ B ]Furan-2-onesmentioning

confidence: 99%

Section: Synthetic Methods Of 2h-cyclohepta[b]furan-2-onesmentioning

confidence: 99%

Synthesis of Azulene Derivatives from 2H-Cyclohepta[b]furan-2-ones as Starting Materials: Their Reactivity and Properties

Shoji

Ito

Yasunami

2021

IJMS

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“…Accordingly, racemic diol 3 and 6, both possessing four stereocenters, were prepared from isopulegol and 4-methyl-tropolone, respectively (Figure 2). The lipase-PS-mediated acetylation reactions were performed by using vinyl acetate and gave enantioenriched monoacetates (+)-4 [21] and (+)-7 [22], respectively, with complete regioselectivity This fragrance occurs as (R)-enantiomer in lavender oil. The racemic alcohol is a cheap commodity, as it is produced by industrial chemical synthesis.…”

Section: Primary Alcoholsmentioning

confidence: 99%

Stereoselective Synthesis of Terpenoids through Lipase-Mediated Resolution Approaches

Serra¹,

Simeis²

2020

Catalysts

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This review article focuses on the scientific developments concerning the lipase-mediated synthesis of terpenoids that have been reported in the literature during the last twenty years. More specifically, this review describes in depth the resolution approaches that allow the preparation of the chiral building blocks used for the stereoselective synthesis of bioactive terpenoids. The synthetic methods that have given new and innovative perspectives from a scientific standpoint, and the preparative approaches that possess industrial importance, are described thoroughly.

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“…Compound III was obtained by reducing DHC through a reaction with LiAlH 4 in tetrahydrofurane. 17 The purity and structure of Compounds I ± IV were confirmed by NMR, UV, IR and MS techniques. 8 Isolation and culture of hepatocytes Wistar rats were obtained from the university breeding colony maintained by the Central Animal House Services.…”

Section: Dhc and Derivativesmentioning

confidence: 99%

Derivatives of dehydrocrotonin, a diterpene lactone isolated fromCroton cajucara: cytotoxicity in rat cultured hepatocytes and in V79 cells

2002

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Derivatives of dehydrocrotonin (DHC; Compound I) with different anti-ulcerogenic properties but less toxicity were produced by reducing the cyclohexenone moiety of DHC with NaBH4 (Compound II), reducing the cyclohexenone and lactone moieties with LiAlH4 (Compound III) and transforming the lactone moiety into an amide (Compound IV) using dimethylamine. Derivatives of DHC were assayed in cultured hepatocytes and V79 fibroblasts. Three independent endpoints assays for cytotoxicity were used, namely, the DNA content, tetrazolium reduction (MTT) and neutral red uptake (NRU). Compound III was less toxic than the other DHC derivatives in both cell cultures. IC50values ranging from 250 to 600 m M were obtained for Compounds II and IV in the NRU and DNA content tests evaluated in 4-hour hepatocyte cultures. Although Compound II showed relatively low cytotoxicity in rat hepatocytes based on the NRU and DNA content assays, a very high toxicity (IC50=10 m M) was observed in the MTT test. Metabolites of Compound II in conditioned medium from 4-hour old hepatocyte cultures enhanced the MTT-reducing ability of V79 fibroblasts. The cytotoxicity of the derivatives was greater in recently isolated hepatocytes (only a 4-hour incubation for cell attachment prior to treating with the derivatives) than in hepatocytes previously cultured (24-hour incubation) before the treatment. Thus, aging reduced the cytotoxic effects of DHC derivatives in isolated hepatocytes, suggesting that P450-mediated biotransformation of such derivatives may lead to the formation of more toxic metabolites.

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Cited by 32 publications

References 34 publications

Synthesis of Azulene Derivatives from 2H-Cyclohepta[b]furan-2-ones as Starting Materials: Their Reactivity and Properties

Synthesis of Azulene Derivatives from 2H-Cyclohepta[b]furan-2-ones as Starting Materials: Their Reactivity and Properties

Stereoselective Synthesis of Terpenoids through Lipase-Mediated Resolution Approaches

Derivatives of dehydrocrotonin, a diterpene lactone isolated fromCroton cajucara: cytotoxicity in rat cultured hepatocytes and in V79 cells

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