排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
Aamer Saeed 《Monatshefte für Chemie / Chemical Monthly》2003,134(3):457-463
Summary. A short facile synthesis of the fungal metabolite (±)-3,4-dihydro-3,6,8-trihydroxy-3- pentadecylisocoumarin (peniolactol)
has been achieved. Condensation of hexadecanoyl chloride with 3,5-dimethoxyhomophthalic acid afforded 6,8-dimethoxy-3-pentadecylisocoumarin,
which on sequential saponification and demethylation furnished rac-peniolactol in 31% overall yield. The ring-chain tautomerism was studied in solution by 1H NMR and the mass fragmentation pattern. 3-Pentadecyl- isocoumarin was also synthesized and saponified to the corresponding
keto acid as a model compound for comparative studies.
E-mail: aamersaeed@yahoo.com
Received May 23, 2002; accepted May 30, 2002 相似文献
2.
Siriporn Saepua Jittra Kornsakulkarn Wiwat Somyong Pattiyaa Laksanacharoen Masahiko Isaka Chawanee Thongpanchang 《Tetrahedron》2018,74(8):859-866
Eleven new compounds, including two quinone derivatives of bioxanthracene, conoideocrellones A (1) and B (2), two bioxanthracenes 3 and 4, four isocoumarins and isocoumarin glycosides 7–10, two phenolic compounds 16 and 17, and a diterpenoid compound, conoideocin A (18), were isolated from culture of the scale-insect pathogenic fungus Conoideocrella tenuis BCC 44534. Seventeen known compounds, compounds 5 and 6, ES-242-2 and its atropisomer, isocoumarins and isocoumarin glycosides 11–15, 3,4,6-trihydroxymellein, cis-4,6-dihydroxymellein, metarhizins A (19) and B (20), BR-050 (21), 5α,8α-epidioxy-24(R)-methylcholesta-6,22-dien-3β-ol, zeorin, and conoideocrellide A, were also isolated from this fungus. Structures of these compounds were elucidated by NMR and MS data analyses. Compound 4 was active against Plasmodium falciparum K1 (IC50 6.6?μg/mL), while it did not show cytotoxicity. Conoideocrellone A (1) and compounds 3 and 7 exhibited cytotoxic activity, while conoideocin A (18) showed broad range of biological activities including antimalarial, antibacterial, and cytotoxic activities. 相似文献
3.
Aamer Saeed 《中国化学会会志》2003,50(2):313-317
A two step synthesis of title isocoumarin isolated from Homalium longifolium and its conversion into corresponding 3,4‐dihydroisocoumarin has been described. 3,4‐Dimethoxybenzoyl chloride on condensation with homophthalic acid afforded 3‐(3′,4′‐dimethoxyphenyl)isocoumarin which was demethylated to furnish the 8‐desoxythunberginol A, whereas its sequential saponification, reduction and demethylation yielded the (±)‐8‐desoxy‐3,4‐dihydrothunberginol A. The synthesized compounds were examined in vitro for antibacterial activity. 相似文献
4.
Ken-ichi Nakashima Junko Tomida Takao Hirai Yuji Morita Yoshiaki Kawamura Makoto Inoue 《Tetrahedron letters》2017,58(23):2248-2251
Three new isocoumarins and two new phthalides, tubakialactones A–E (1–5), together with three known polyketides including (R)-3,4-dihydro-4-hydroxyl-6,8-dimethoxy-4-methyl-3-methylene-1H-2-benzopyran-1-one (6), (?)-5,7-dimethoxy-3-methyl-1(3H)-isobenzofuranone (7), and isosclerone (8) were found in the endophytic fungus Tubakia sp. ECN-111 isolated from the leaves of Houttuynia cordata. The chemical structures of the new compounds were determined by spectroscopic analyses, including extensive 2D-NMR experiments. The absolute configuration of 3 and 7 was determined by optical rotation and circular dichroism. 相似文献
5.
Mengli Sun Lebin Su Jianyu Dong Long Liu Yongbo Zhou Shuang-Feng Yin 《Tetrahedron letters》2017,58(25):2433-2437
An efficient method for the synthesis of 3-substituted isocoumarins that are an important class of biologically active scaffolds via annulation of 2-bromobenzoic esters with terminal alkynes by copper catalyzed is described. The advantages of this method include mild reaction conditions, high yield and regioselectivity, and wide tolerance toward functional groups. 相似文献
6.
Reaction of an isocyanide with an iminium ion intermediate, formed by reaction between 2‐formylbenzoic acid and dibenzylamine in the presence of silica nanoparticles (silica NP, ca. 42 nm) proceeds smoothly at room temperature to afford isocoumarin (=1H‐2‐benzopyran‐1‐one) derivatives in high yields (Scheme 1 and Table 1). 相似文献
7.
Treatment of methyl 2‐alkynylbenzoates with two to three equivalents of CuX2 (X = Cl or Br) in refluxing acetonitrile gave isocoumarins 2 in good to excellent chemical yields. 相似文献
8.
A simple and efficient Rh(III)-catalyzed C-H activation and tandem intramolecular cyclization for the synthesis of isocoumarins has been developed. The protocol uses easily available primary benzamides and cyclic 2-diazo-1,3-diketones as starting materials. This reaction proceeds via C-C and C-O bond formation in a single reaction vessel, and the corresponding isocoumarins were obtained in moderate to excellent yields (58%–97%). The well established protocol showed high functional group tolerance, which provided an efficient and alternative route to isocoumarin backbone. 相似文献
9.
4‐Arylisocoumarins (=4‐aryl‐1H‐2‐benzopyran‐1‐ones) 6 were prepared from 2‐(1‐aryl‐2‐methoxyethenyl)‐1‐bromobenzenes 1 . Successive treatment of these bromo styrenes with BuLi and 1‐formylpiperidine gave a mixture of (E)‐ and (Z)‐2‐(1‐aryl‐2‐methoxyethenyl)benzaldehydes 2 . Hydrolysis of (Z)‐isomers with conc. HBr, followed by pyridinium chlorochromate (PCC) oxidation of the resulting 1H‐2‐benzopyran‐1‐ol derivatives 4 (and 5 ), afforded the desired products. 相似文献
10.
Ihsan Ullah Muhammad Sher Rasheed Ahmad Khera Muhammad Farooq Ibad Christine Fischer 《Tetrahedron》2010,66(10):1874-1884
The [3+3] cyclization of 1,3-bis(silyloxy)-1,3-butadienes with 1-hydroxy-5-silyloxy-hex-4-en-3-ones resulted in the one-pot formation of 3-aryl-3,4-dihydroisocoumarins. The reactions proceeded by regioselective cyclization to give 6-(2-aryl-2-chloroethyl)salicylates, which underwent a silica gel-mediated lactonization. The cyclizations of protected 1-amino-5-silyloxy-hex-4-en-3-ones proved to be not regioselective. 相似文献