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1.
《Tetrahedron: Asymmetry》1999,10(12):2429-2439
Enzymatic glycosidation of the various kinds of primary alcohols 5, 7, 9, 11, 13 and 15 and 4-nitrophenyl-β-d-glucopyranoside 4 using β-glucosidase from almonds gave stereoselectively β-d-glucosides 6, 8, 10, 12, 14 and 16 including the naturally occurring β-glucosides in moderate yield. Among them, the β-glucosides 6, 8 and 10 were converted to the cyanoglycosides, rhodiocyanoside A 20a, osmaronin 24a and sutherlandin 29, respectively. 相似文献
2.
Reaction between 2-vinyl pyridine and azodicarboxylates 2 or 5 gives N,N'-disubstituted tetrahydropyrido[3,2-c]pyridazines 3 and 6, and dihydro-3H-pyrido[1,2-c]triazines 4 and 7; 2-(prop-1-en-1-yl)-pyridine 8 gives hydropyridopyridazines 10 and 11 but 2-(prop-1-en-2-yl)pyridine 9 gives mainly the ‘ene’ addition product 12. From 4-vinyl-pyridine and esters 2 or 5 diesters of tetrahydropyrido[3,4-c]pyridazine-1,2-dicarboxylic acid, 25 and 26 are obtained, and from 2-methyl-5-vinylpyridine both possible cyclisation products, the tetrahydro-pyrido[2,3-c]pyridazines 33 and 36, and -pyrido[4,3-c]pyridazines 34 and 37. The di-t-butyl esters 6, 11, 26, and 37 are quantitatively decarbalkoxylated in TFA, giving tetrahydropyridopyridazines 16, 18, 27, and 41; of these, the first three were oxidized to give pyrido[2,3-c]-pyridazine 15, its 3-methyl derivative 19, and pyrido[3,4-c]pyridazine 28 respectively. A dihydropyrido[4,3-c]-pyridazine 42 was obtained from compound 41. Thieno[2,3-c]-pyridazine 48 has been similarly prepared from 2-vinylthiophen, but 2-(prop-1-en-2-yl)thiophen gave an ene addition compound 51 and a dihydrothienopyridazine 50. Reactions with other vinylpyridines, and with vinylfurans, were unsuccessful. 相似文献
3.
3,1-Benzoxathian-4-ones, 2, when heated with 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2, 4-disulfide, 1, or with P4S10 give one or more of the following products 3,1-benzoxathian-4-thione, 3, 1,3-benzodithian-4-one, 4, 1,3-benzodithian-4-thione, 5, and 3H-1,2-benzodithiole-3-thione, 6. Compounds 2, when heated with primary and secondary amines and with hydrazines, give 2-mercaptobenzamides, 7, and 2-mercaptobenzohydrazides, 8, or their corresponding disulfides, 7' and 8'. 3H-1, 2-Benzodithiol-3-immes, which are in equilibrium with 1,2-benzisothiazole-3(2H)-thiones, (9A ? 9B), are prepared by two new routes (a) by allowing 3 or 5 to react with primary amines or hydrazines, (b) by allowing 7, 8, 7' or 8' to react with 1. 相似文献
4.
The synthesis of the perhydroisoindole systems 17a, b, 22 and 23 is described using the following sequence of reactions. Diels-Alder cycloaddition of silyloxydienes 4 with methyl acrylate leads, after methanolysis, to cyclohexenonecarboxylates 6, subsequent acetalization and epoxidation of the α,β-unsaturated esters 7 yields the epoxy esters 8 and 9. Conversion of these esters into acyl chlorides 11, via the sodium salts 10, and subsequent treatment with an amine component (phenylalanine methyl ester, diethyl aminomalonate and ethyl 2-amino benzoyl-acetate) produces the epoxy carbonamides 12, 15 and 18, respectively. These epoxy amides are subjected to acid-catalyzed hydrolysis to give the cyclohexenonecarbonamides 13, 16 and 19, respectively. Subsequent ring-closure of the amides 16 and 19 with base leads to the perhydroisoindole derivatives 17a, b and 22, respectively. The formation of 22 proceeds via a concomitant benzoyl transfer reaction. The amide 13 failed to ring-close. A by-product of the acid treatment of 18 is 21 which with base undergoes a benzoyl transfer to perhydroisoindole 23. The structures of the products 9a, 22 and 23 were ascertained by means of an X-ray analysis. 相似文献
5.
Tadashi Sasaki Katsumaro Minamoto Toshimichi Suzuki Shunsuke Yamashita 《Tetrahedron》1980,36(7):865-870
In search for a simpler model system for the study of intramolecular thermal reactions between the base and 5'-functionalized sugar moiety in nucleosides, 1-(3-azidopropyl)uracil (2), 1-(4-azidobutyl) pyrimidines (12 and 13) and 1-(5-azidopentyl)-uracil (14) was synthesized through the corresponding ω-benzoyloxy-(6,7 and 8) and ω-hydroxyalkyl-pyrimidines (9,10 and 11). Heating 2 gave 1,N6-trimethylene-6-aminouracil (4), while heating 12 and 13 gave N1-C6 cleaved addition products. 15 and 16, respectively. 15 was regiospecifically transformed to 1,2,3-triazole derivatives, 17,18 and 19. Heating 1-(4-azidobutyl)-5-bromouracil (20) yielded 3,9-tetramethylene-8-azaxanthine (22). 9 with NBA gave 1,06-tetramethylene-5-bromo-6-hydroxy-5,6-dihydrouracil (24) and the 5-brominated analog of 9 (25). The 4-functionalized butyl side chain proved to serve as a substitute for the 5'-functionalized sugar moiety in pyrimidine ribonucleosides. 相似文献
6.
Jittra Kornsakulkarn Siriporn Saepua Kitlada Srichomthong Sumalee Supothina Chawanee Thongpanchang 《Tetrahedron》2012,68(40):8480-8486
Nine new mycotoxins; five xanthones 1–5, hydroxanthone 6, and three anthraquinones 7–9, together with nine known compounds; sterigmatocystin (10), demethylsterigmatocystin (11), dihydrodemethylsterigmatocystin (12), sterigmatin (13), austocystin F (14), averufin (15), aflatoxin B1, paeciloquinone A, and zeorin, were isolated from the scale insect fungus Aschersonia coffeae Henn. BCC 28712. The structures of these compounds were elucidated using NMR spectroscopic and MS spectrometric analyses. Compounds 1–3 and 6–9 displayed cytotoxic activity while the xanthone 2 and anthraquinones 8 and 9 also showed antimalarial activity. 相似文献
7.
《Tetrahedron: Asymmetry》2006,17(2):259-267
The development of three new acidic resolving agents which are hydrogen phthalates of 1,2:5,6-di-O-isopropylidene-α-d-glucofuranose 1, 1,2:5,6-di-O-cyclohexylidene-α-d-glucofuranose 2 and 1,2-O-cyclohexylidene-5,6-O-diphenylmethylidene-α-d-glucofuranose 3 is shown for the resolution of 1-arylalkylamines 7a–k. The salts between 1, 2 and (RS)-1-arylalkylamines 7a–k selectively crystallize 1·(S) 7a–j and 2·(S) 7a–h salts, allowing us to recover the corresponding bases (S) 7a–j and (S) 7a–h, respectively, in good yield and enantiomeric excess (73–95% ee). Whereas, the salts between 3 and (RS)-1-arylalkylamines 7a–c,g–i,k selectively crystallize 3·(S)-7a–c,g–i salts to recover the corresponding bases (S)-7a–c,g–i in poor enantiomeric excess (4–35% ee). The difference between the resolving ability of 1 and 2 for 1-arylalkylamines 7a–h is very slight, but there is considerable difference compared to ortho-substituted 1-arylalkylamines 7i and 7j. The role of substituents on a family of resolving agents 1, 2 and 3 is also discussed to interpret their resolving ability. 相似文献
8.
Wirongrong Kaweetripob Chulabhorn Mahidol Siriporn Wongbundit Pittaya Tuntiwachwuttikul Somsak Ruchirawat Hunsa Prawat 《Tetrahedron》2018,74(2):316-323
Sesterterpene, erectusolide A (1), six phenolic alkenes, erectuseneols A?F (2–7) and nine known compounds, luffalactone (8), luffariolide E (9), (6E)- and (6Z)-neomanoalide 24,25-diacetates (10 and 11), 6,6-dimethylundecane-2,5,10-trione (12), threo- and erythro-cavernosines (13 and 14), (4E,6E)-dehydromanoalide (15), echinoclerodane A (16), were isolated from the marine sponge Hyrtios erectus. Compound 13 was isolated for the first time from a natural source. The structures of these compounds were elucidated on the basis of spectroscopic analysis. The phenolic alkenes 3 and 7, the sesterterpenes 8–11 and 15, and compounds 12–14 were evaluated for cytotoxic activities against six cancer cell lines, MOLT-3, HepG2, HeLa, HuCCA-1, A549, and MDA-MB-231. 相似文献
9.
The bis-peroxide 5 was obtained by sensitized photo-oxidation of benzhydrylidene-cyclobutane 1. The structure was established on the basis of a series of reactions, including selective acidolysis (to the hydroperoxides 11) and reductions of the bis-peroxide 5 (to the diols 6, 8 and tetrol 9) and some of its derivatives (to the diols 7, 21 and derivatives, epoxide 12, alcohol 13, triol 14, tetrols 15, 22), and partial oxidative degradations (to the bis-hemiacetal 17, hemiacetal-lactone 18, ketol 19, and lactones 27, 28, 29). The configurations and conformations of all the derivatives were established by NMR spectroscopy including the use of a europium shift reagent. 相似文献
10.
Hydroboration of aziridines having a β or γ-double bond 3b, 3c, 4b, 7c and 8 yields after oxidation, the expected hydroxy aziridines 11b, 11c, 12b, 13 and 14, which were cyclized by reaction with PPh3/Br2 to give 1-aza bicyclo[n, 1, 0]alkanes 23b, 24b, 25c, 26 and 27. The hydroboration of 2-vinyl aziridines 3a, 4a and 7a give Z-allylic amines 16aZ, 17aZ and 18Z. The use of 9-BBN or of 2-vinyl substituted aziridines provides the β-hydroxy aziridines 19, 20 and 21. 相似文献
11.
Reaction of benzthiazol-2-yl and benzoxazol-2-yl-trimethylstannane with methyltrichlorogermane leads to the mono-, bis- and tris-heterocyclic substituted germanes RGe(Me)Cl2, R2Ge(Me)Cl, R3GeMe (2, 3, 4: R = benzthiazol-2-yl; 6, 7, 8: R = benzoxazol-2-yl), which exist in a mobile equilibrium. From the chlorogermanes 2, 3 and 6, 7 the corresponding germanes 9, 10 and 11, 12 can be obtained by reaction with trimethylstannane. From the germane 10 the mono- and bis-N-methylated salts 15 and 17 can be synthesized. The compounds 10, 12 and 15 easily decompose by α-elimination reactions. The salt 17 can be regarded as a suitable model substance for the synthesis of a germacyanine dye. 相似文献
12.
《Arabian Journal of Chemistry》2022,15(11):104292
Six new compounds (huangjusus A-F), including three caffeic acid glycosides (1–3), one quinic acid derivative (4), one dihydroflavone glycoside (11) and one monoterpene (31), together with thirty-eight known compounds (5–10, 12–30, 32–44), were obtained from “Jinsi Huangju” (Chrysanthemum morifolium Ramat.) flowers. Their structures were elucidated on the basis of the data obtained from different spectroscopic techniques. Among these compounds, five new (1–4 and 11) and ten known (5–9, 12, 13, 17, 40, and 42) compounds demonstrated significant 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging effects with IC50 values of 4.22–19.90 μM. Furthermore, three new compounds (1, 11, and 31) and seven known compounds (13, 19, 21, 29, 30, 39, and 41) exhibited potent hepatoprotective activities against N-acetyl-p-aminophenol (APAP)-induced toxicity in HepG2 cells with the cell survival rates of 61.53 %, 63.55 %, 60.01 %, 63.05 %, 59.75 %, 59.15 %, 61.07 %, 62.72 %, 58.86 %, and 58.76 % (positive control bicyclol, 58.41 %), respectively, at a concentration of 10 μM. These results indicate the potency of the flowers against radicals and in hepatoprotections. 相似文献
13.
《Tetrahedron》2014,70(51):9601-9614
3,6-Bis-(2-indolyl)dibenzofurans 1,2, and carbazoles 3–6 underwent a range of electrophilic substitution reactions to produce formyl indoles 7–12, biindolyls 24–28 and 33–34, glyoxylamides 40–42, and amides 48. 相似文献
14.
Ethenamine 1 and its methyl derivatives 2–7 have been synthesized from the adducts 8–14 by a retro-Diels-Alder reaction under flash thermolytic conditions. The primary enamines 1–4 have been identified (IR, 1H and 13C NMR) in a pure state at ?80°; at the same temperature, the enamines 5–7, less stable, are already accompanied by their tautomeric imines 33 or 34. When warmed up to room temperature, the enamines 1–7 lead, following to their substitution, either to nitrogen heterocycles (30, 42) or to acyclic azadienes (35–37, 39, 40). 相似文献
15.
Diphenyldiazomethane with compound (1) gave dibenzoyl, while 2 and 3 gave the corresponding 3-oxo(2H)thiophenes 5. With copper-bronze 1 gave 2,2′-di-(thiobenzoate) (4), while 2 gave 2,7-diphenylthiepin (6a) and 2,5-diphenylthiophene (7a), but 3 gave only 2,5-di-(p-methoxyphenyl)thiophene (7b). With Grignard reagents 1 gave the corresponding methanol derivative 14, while 2 gave the thiobenzoylethylenes 13a and b, but 3 gave 2,7-di-(p - methoxyphenyl) - 4,4,5,5- tetraphenyl(4H)thiepin (15). The reaction mechanisms are discussed. 相似文献
16.
Disodium salt 2 reacts with hydrogen peroxide to give 1,2,4-trithiolane 3, whereas treatment with methyl chloroformate yields 1,3-dithietane 4. Adding diluted NaOH to 3 leads to a mixture of an isothiazole 7 and 4. By chlorination of 2 isothiazole 8 is available. S-amination of 2 or 9 and following cyclization gives the isothiazoles 10 and 12, respectively. 3-Mercapto-acrylonitrile 14 reacts with quinones to condensed oxathioles 16 or 17. 相似文献
17.
Huei-Jyun Shih Yen-Ju Tseng Chiung-Yao Huang Zhi-Hong Wen Chang-Feng Dai Jyh-Horng Sheu 《Tetrahedron》2012,68(1):244-249
Seven new diterpenoids, namely, flexibilisolides C–G (1–5), flexibilisin C (6), and a novel 11,12-secoflexibillin (7), along with seven known compounds, 8–14, were isolated from the Dongsha Atoll soft coral Sinularia flexibilis. The structures of the new metabolites were elucidated by extensive spectroscopic analysis and comparison of the NMR data with those of known analogues. Compounds 1, 8, and 11 were shown to exhibit moderate cytotoxic activity against HeLa and B16 cancer cell lines, and compound 10 was found to exhibit more potent cytotoxic activity against SK-Hep1 and B16 cancer cell lines. Moreover, compounds 1, 2, 8, 9, and 11–14 could significantly inhibit the accumulation of the pro-inflammatory iNOS protein and 1, 8, 11, and 14 could reduce the accumulation of COX-2 protein in LPS-stimulated RAW264.7 macrophage cells. 相似文献
18.
M. Harnik R. Szpigielman Y. Lederman J. Herling E. Abramovichi Z.V.I. Zaretskii 《Tetrahedron》1976,32(1):79-88
While hydrogenations of 2b furnished a mixture in which the rac 14α isomer 8b predominated, the rac lactone 6 was hydrogenolyzed to give the rac 14β diacid 9a. Clemmensen reduction of 6 gave the rac 14α tetrahydro compound 7a. Another route to 8 involved conversion of the d-ketoacid 11b into 23b via the cyanolactone 20b or the amidolactone 21b. Base-catalyzed elimination at 206° yielded the Δ16 diester 27 which was hydrogenated to 8c. An analogous conversion was also carried out in the ring B reduced series 13 → 20a + 21a → 23a → 25a → 26. In the 14β series, using the same sequence of reactions, the rac ketoacid 10a was transformed into the rac lactone ester 29. In distinction from the 14α series, treatment with alkali at 206° gave only partial elimination, the double bond migrating to the 14,15 position to furnish 2. Evidence is presented that amides of the ketoacid 13a exist in the hydroxylactam form 30 and can be readily O-alkylated to furnish 22. Attempts to aromatize ring B of 13a with DDQ led to lactones 15 and 16, while reaction of the ester 13b with DDQ gave the pentaene 17 and the hexaene 18, establishing that dehydrogenation proceeded stepwise in the sequence Δ8, Δ14 and finally Δ6. 相似文献
19.
Coronene tatracarboxylate CTC and octacarboxylate COC have been utilized to interact with dipyridinium DP and tetrapyridinium TP to assemble new supramolecular polymers in water. It was revealed that CTC interacted with DP and TP in 1:2 and 1:1 stoichiometry, whereas the binding between COC and DP and TP occurred in 1:4 and 1:2 stoichiometry. For all complexations, DP and TP behaved as a uni- or siamesed tweezers to clamp CTC or COC driven by ion-pair attraction and hydrophobically driven stacking of the pyridinium and coronene units. Apparent association constants were determined to be 33400 (CTC/DP), 9400 (COC/DP), 151000 (CTC/TP), and 89000 (COC/TP) M?1, respectively, for the single clamping binding motif of the four complexes. Dynamic light scattering and isothermal titration calorimetric experiments supported that the mixtures of CTC and COC with TP formed linear and cross-linked supramolecular polymers. 相似文献
20.
Eslam Reda El-Sawy Adel Hamed Mandour Salwa M. El-Hallouty Kamel Hussein Shaker Heba Mohamed Abo-Salem 《Arabian Journal of Chemistry》2013,6(1):67-78
A series of 1-(N-methyl 2a–c and N-benzenesulphonyl-1H-indol-3-yl)-3-aryl-prop-2-ene-1-ones 3a–c were prepared and allowed to react with urea, thiourea or guanidine and gave the pyrimidine derivatives 4a–c to 9a–c. Base catalyzed reaction of 2a–c or 3a–c with ethyl acetoacetate gave cyclohexanone derivatives 10a–c and 11a–c, respectively. Reaction of the latter compounds with hydrazine hydrate afforded indazole derivatives 12a–c and 13a–c, respectively. On the other hand, condensation of 2c or 3c with some hydrazine derivatives namely, hydrazine hydrate, acetyl hydrazine, phenyl hydrazine and benzyl hydrazine hydrochloride gave pyrazole derivatives 14a,b-17a,b, respectively. Moreover, reaction of 2c or 3c with hydroxyl amine hydrochloride gave isoxazole derivatives 18a,b. The newly synthesized compounds were tested for their antimicrobial activity and showed that, compounds 14a, 14b, 15a and 15b were found to be the most active ones of all the tested compounds toward Salmonella typhimurium (ATCC 14,028) compared to the reference drug chloramphenicol. Eighteen new compounds namely, pyrimidin-2(1H)-ones 4a–c and 5a–c, pyrimidin-2(1H)-thiones 6a–c and 7a–c and pyrimidin-2-amines 8a–c and 9a–c were tested for their in vitro cytotoxicity against human liver carcinoma (HEPG2), human breast cancer (MCF7) and human colon cancer (HCT-116) cell lines and showed that, compounds 4c, 5c, 6c, 8c and 9c were found to be the highly active compounds compared to the reference drug doxorubicin. 相似文献