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1.
F. M. Soliman Kh. M. Khalil G. Abd-el-naim 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4)
Abstract The reaction of 1,2-benzo [a] phenazine-8, 9-dione 1 and/or 1,2,3-indantrione 2, with phosphonium ylides has been studied. When 1 was reacted with two molar amounts of methoxy-(3a) and/or ethoxycarbonylmethylenetriphenylphosphorane (3b), in THF, at the reflux temp, for 3 hrs, dimethyl (4a) and/or diethyl 1,2-dihydrobenzo a furo [3,2-h] phenazine-1,2-dicarboxylate (4b), along with triphenylphosphine oxide and triphenylphosphine were obtained. On the other hand, reaction of equimolar amounts of ylides 3 with the red trione 2 in THF at room temp., afforded colourless crys tals of 2′,4′-dihydroxyspiro [indan-2,3′ (2′H)-indeno [1,2-b] pyran]-1,3,5′(4′H)-trione diacetate (5a) or dipropionate (5b), together with triphenylphosphine oxide. Formation of 6-membered dihydro aromatic ring like 5, is considered as a new reaction of phos phoranes. The structure of the new compounds 4 and 5 was confirmed and the reaction mechanisms are discussed. 相似文献
2.
Heterobicycles of δ-lactam fused with imidazolidine (4, 7), hexahydropyrimidine (5, 8), or hexahydro-1, 3-diazepine (6, 9) were synthesized by the reaction of heterocyclic ketene aminals 1, 2 or 3 with ester of α,β-unsaturated carboxylic acids. 相似文献
3.
Michael D. Threadgill 《合成通讯》2013,43(12):1101-1105
In a report on the reaction of 2-chloronitrobenzene (1) with diethanolamine (2), Meltsner et al 1 claim that the expected SNAr product, N-(2-nitrophenyl)diethanolamine (3), is not formed; rather that the products are 2,2′-dichloroazobenzene (4), 2-nitrophenol (5), 2-chloroaniline (6) and 4-(2-aminophenyl)morpholine (7). Similar products in which the nitro function is reduced are also reported2 for the corresponding reaction with ethanolamine. In this laboratory, in an attempted preparation of 2,2′-dichloroazobenzene (4) for reference purposes in photochemical studies on the antineoplastic agent 5-(3-azido-4-chlorophenyl)-6-ethyl-pyrimidin-2,4-diamine3, the expected SNAr product (3) was obtained along with other products. 相似文献
4.
1R-cis-2,2-Dimethyl-3-(2,2-dibromovinyl)cyclopropane carboxylic acid1 (1), the acid moiety of the highly potent photostable pyrethroid deltamethrin (2) has been obtained either by a Wittig reaction on 1R-cis-caronaldehyde ester (3) employing 1, 1-dibromomethylenetriphenylphosphorane or from the bicyclic tribromo-lactone2,3 (4) by reaction with zinc and acetic acid. Lactone (4) is thus an important intermediate in the deltamethrin synthesis. 相似文献
5.
Abstract The reaction of N-phenyliminoketenylidenetriphenylphosphorane [a] (1), with 2-benzylidene-1, 3-indandione (2), 1,2-diphenyl-3,4-pyrazolidenedione (3)and/or 5-benzylidene barbituric acid (4) has been investigated. When ylide 1 was allowed to react with compounds 2, 3 or 4 in THF at ambient temp. the corresponding new pyrano-phosphoranylidenes 5, 6 or 7 were obtained. The elemental microanalyses, IR, 1H NMR, 31P NMR and MS data agree with the structure of the cyclic iminophosphoranes by [4+2]-cycloaddition and exclude 4-membered ring structure by [2+2]-cycloaddition. When the Wittig reaction was carried on the pyrano-phosphoranes 5, 6 or 7 using p-nitrobenzaldehyde, the exocyclic olefins together with triphenylphosphine oxide were isolated. 相似文献
6.
Abstract Reactions of 2′,3′,4′,2″,6″-penta-O-acetyl-tetra-N-tert-butyloxycarbonyl-kanamycin-A-4″-brosylate (4b) or-4″-triflate (4c) with acetate, thiolacetate, azide, and fluoride, respectively, result in the formation of the corresponding derivatives of 4″-epi-kanamycin A (5a-d). While 4b invariably forms an elimination byproduct (9), the only side—reaction of 4c consists in a neighboring group attack with formation of a 3″-epi-4″-cyclic urethane (7). Removal of the protecting groups yields 4″-epi-(6a), 4″-thio-4″-epi-(6b), 4″-deoxy-4″-fluoro-4″-epi-(6d), 4″-azido-4″-deoxy-4″-epi-(6c), and after hydrogenation of the latter, 4″-amino-4″-deoxy-4″-epi-kanamycin A (6f). Methyl 2,6-di-O-acetyl-3-amino-3-N-tert-butyloxycarbonyl-3-deoxy-4-O-triflyl-β-D-glucopyranoside (1b) served as a model to anticipate preparation, handling, and reactivity of 4c. 相似文献
7.
4-Aroyl-3-chloro-6-p-tolylpyridazines (3a &b) were prepared by the action of phosphorous oxychloride on (2). (3a &b) react with hydrazine hydrate to give the pyrazolinopyridazines (4a &b) and with hydroxylamine hydrochloride to give the isoxazolopyridazines (7a &b), respectively. (4b) was also synthesized by the action of phosphorous oxychloride on the hydrazone (5). The reaction of (3a &b) with primary amines in boiling ethanol gives (8a-e), while their reaction with primary aromatic amines in the presence of solvent gives the Schiff's bases (9a-c). 相似文献
8.
The reaction of 2,3-dihydrofuran (1), dihydropyran (2) and indole (8) with acyloxysulfonium salt (3) and Methyl amine furnished vinyl sulfides 6, 7 and 10 respectively in very good yields. 相似文献
9.
Makoto Kiso Yuji Ogawa Yushun Fujishima Minoru Fujita Shinji Tanaka Akira Hasegawa 《Journal of carbohydrate chemistry》2013,32(4):625-638
Abstract In order to elucidate further the relationship between the composition of the fatty acyl groups in the nonreducing-sugar subunit of bacterial lipid A and its biological activity, 3-O-[(3R)-3-(acyloxy)tetradecanoyl]-2-deoxy-2-[(3R)-3-hydroxytetradecanamido]-4-O-phosphono-D-glucose [GLA-63(R, R) and GLA-64(R, R)], and 3-O-[(3R)-3-(acyloxy)tetradecanoyl]-2-deoxy-4-O-phosphono-2-tetradecanamido-D-glucose [GLA-67(R), GLA-68(R) and GLA-69(R)] have been synthesized. Benzyl 2-[(3R)-3-(benzyloxymethoxy)tetradecanamido]-2-deoxy-4,6-O-isopropylidene-β-D-glucopyranoside (5) and benzyl 2-deoxy-4,6-O-isopropylidene-2-tetradecanamido-β-D-glucopyranoside (6) were each esterified with (3R)-3-dodecanoyloxytetradecanoic acid (1), (3R)-3-tetradecanoyloxytetradecanoic acid (2) or (3R)-3-hexadecanoyloxy-tetradecanoic acid (3), to give 7-11, which were then transformed, by the sequence of deisopropylidenation, 6-O-tritylation and 4-O-phosphorylation, into a series of desired compounds. 相似文献
10.
α-Bromoacetals (1) are valuable precursors in synthesis of α,β-unsaturated carbonyl compounds (2), 1-alkoxybutadienes2 (3), ketene acetals3 (4), 2-methoxyallyl bromides4 (5) and other compounds. Because of our interest in the chemistry5,6 of 3 and 4 we attempted to improve known procedures for the preparation of 1 with the aim to get a short and efficient synthesis of these compounds. 相似文献
11.
Pavol Kováč Herman J. C. Yeh Grace L. Jung Cornelis P. J. Glaudemans 《Journal of carbohydrate chemistry》2013,32(3):497-512
Methyl 3-O-benzyl-4, 6-O-benzylidene-α-D-mannopyranoside (2), when treated in diglyme at 1000[ddot] with DAST, undergoes a rapid reaction involving the participation of the axial methoxyl group at C-1 to give 3-O-benzyl-4, 6-O-benzylidene-2-O-methyl-α- (4) and β-D-gluco-pyranosyl fluoride (3), isolated in a combined yield of 75-80%. In the presence of pyricfine and at room temperature, the major product formed is methyl 3-O-benzyl-4, 6-O-benzylidene-2-deoxy-α-D-eiythro-hex-2-enopyranoside (11). The structures 3, 4 and 11 have been confirmed by analysis of their NMR spectral data, as well as by chemical transformations into compounds of established structure. 相似文献
12.
Burdica Ljevaković Jaroslav Horvat Branimir Klaić Srdanka Tomić 《Journal of carbohydrate chemistry》2013,32(3):263-278
Abstract Fully protected 1-thioglycopyranosyl esters of N-acylamino acids (5, 6, and 7) were prepared by condensation of methyl 2, 3, 4-tri-O-acetyl-1-thio-β-d–glucopyranuronate (1), 2, 3, 4-tri-O-acetyl-1-thio-l–arabinopyranose (2), and 2, 3, 4-tri-O-acetyl-1-thio-D-arabinopyranose (3) with pentachlorophenyl esters of N-acylamino acids in the presence of imidazole. The 13C NMR chemical shifts of the starting 1-thio sugars and the 1-thiol ester products are reported. 相似文献
13.
N-(2-Bromoethyl)phthalimide (1) was reacted with sodium imidazolate in DMF to give the novel aminal N-[1-(1H-imidazol-1-yl)ethyl]phthalimide (4a) as well as N-vinylphthalimide (3) and the desired Gabriel intermediate 2. Aminal 4a as well as heterologues 4b - d form directly from reaction of 3 with the appropriate heterocyclic sodium salt. 相似文献
14.
The bicyclic coumarin derivative-1, 3 propano-2-bromo-1,2-dihydro-3H-pyrano [2, 3-c] [1]benzo-pyran-5-one (8) was synthesised by a sequence of reaction viz. acetylation of 4-[2′-cyclohexenyl] -3-hydroxy [1] benzopyran-2-one (4), addition of bromine to cyclohexenyl double bond and treating the resulting acetyldi-bromo derivative (7) with 4% alcoholic KOH. Benzofuro [2, 3-c] [1] -benzopyran-6-one (10) was synthesised from 4 via oxymercuration with mercuric acetate in methanol followed by dehydrogenative damercuration with Pd-C in refluxing diphenyl ether. 相似文献
15.
Giovanni Frenza Claudio Fuganti Piero Grasselli Giuseppe Pedrocchi-fantoni 《Journal of carbohydrate chemistry》2013,32(3):225-248
Abstract The erythro and threo chiral C5 methyl ketones (4) and (5), prepared from the (2S, 3R)-methyl diel (1b), were converted into the phenylsulfenimines (6) and (7), which, in turn, on reaction with allyl-magnesiutn bromide, yielded after acid hydrolysis and benzoylation, the diastereoisomeric C8-N-aminodiol derivatives (9) and (11), with threo stereochemistry relative to positions 4 and 5. Ozonolysis of (9) and (11) yielded the l-arabino and l-xylo 3-O-methyl branched aminodeoxysugar derivatives (13) and (15), respectively. Using diallylzinc as the reagent, the diastereoisomeric erythro products (8) and (10) were obtained. The latter materials gave the l-ribo-and l-lyxo-(lL-vancosamine) derivatives (12) and (14) upon oxonolysis. The 1H and 13C NMR spectra of the four isomeric aminodeoxysugar derivatives (12)—(15) were discussed. 相似文献
16.
α-Dithiophosphates of peracetylated 2-deoxyhexc-pyranoses, 1a, 1b and 2, uhich are easily prepared by addition of organic phosphorodithioic acids to glycais react smoothly with resin-bound 2- and 4-nitrophenoxides to give stereoselectively the respective nitrophenyl 2-deoxy-β-D-hexopyranosides (3, 4, 5 and 6) in high yields. Glycosylation of the 2, 4-dinitro'phenoxide, however, leads with comparable stereoselectivity to 2,4-dinitrophenyl 2-deoxy- α-D-hexopyranosides (7 and 8). Glycosides 3 - 6 are quantitatively deacetylatec by Amberlyst A-26 (OH-), whereas glycosides 7 and 8, under the same reaction conditions undergo splitting of the O-glycosidic bond. 相似文献
17.
Rajan N. Shah José Baptista Guillermo R. Perdomo Jeremy P. Carver Jiri J. Krepinsky 《Journal of carbohydrate chemistry》2013,32(4):645-660
Abstract Selective acetolysis of methyl 2, 3, 4, 6-tetra-O-benzyl-α-D-manno-pyranoside (2) allows for easy preparation of 1-acetates of 2, 3,4, 6-tetra-O-benzyl (5), 6-O-acetyl-2, 3, 4, tri-O-benzyl-(6), 4, 6-di-O-acetyl-2,3-di-O-benzyl-(7), 3, 4, 6-tri-O-acetyl-2-O-benzyl-(8), and 2, 4, 6-tri-O-acetyl-3-O-benzyl-D-mannopyranoside (9). 8 and 9 formed are separated by preparative HPLC in 30-60g scale. The time course of previously described acetolyses of 3, 4, 6-tri-O-benzyl- 1, 2-O-(1-methoxyethyidene)-β-D-mannopyranose (3), and methyl 2, 3-dt-O-benzyl-4, 6-O-benzylldene-α-D-mannopyranoside (4) giving 9, 1, 2, 6-tri-O-acetyl-3, 4-di-O-benzyl-(10), and 1, 2-di-O-acetyl-3, 4, 6-tri-O-benzyl-(11) α-D-mannopyranose as well 7 have been studied. 相似文献
18.
Treatment of methyl 4-O-benzoyl-2, 6-dideoxy-β-D-arabino-hexopyranoside (6) with triflic anhydride in The presence of 2, 6-di-t-butyl-4-methylpyridine (7) produces methyl 4-O-benzoyl-2, 6-dideoxy-3-O-(tri-fluoromethylsulfonyl) -β-D-arabino-hexopyranoside (8), a compound which rearranges to a new and highly unstable triflate (10) upon standing at room temperature. Bromide ion reacts with 10 to give methyl 4-O-benzoyl-3-bromo-2,3,6-trideoxy-β-D-arabino-hexopyranoside (11), a product of displacement at C-3. A similar reaction takes place with nitrate ion to give methyl 4-O-benzoyl-2, 6-dideoxy-3-O-nitro-β-D)-arabino-hexopyranoside (15). Reaction of 10 with water and with tributyltin hydride results in capture of the cation 12, formed by ionization of 10, to give methyl 3-O-benzoyl-2,6-dideoxy-β-D-ribo-hexopyranoside (14) and methyl 3, 4-O-benzylidene-2, 6-dideoxy-β-D-ribo-hexopyranosi de (16), respectively. The cation 12 also reacts with methanol to afford the orthobenzoates 17 and 18. 相似文献
19.
Sylvie Pochet Patrice Allard Tam Huynh-dinh J. Igolen 《Journal of carbohydrate chemistry》2013,32(3):277-288
Abstract A scheme of asymmetric synthesis of C-glycosyl α-glycines is described. Reductive hydrolysis of 2-deoxy-3,5-di-O-p-toluoyl-β D-erythropentofuranose 1-cyanide (4) in the presence of N,N-diphenylethylenediamine gave the imidazolidine 5, which was converted to 2,5-anhydro-3-deoxy-4,6-di-O-p-toluoyl-β-D-allose (3)by acid hydrolysis. The aldehyde (3), chiralamine, benzoic acid and t-butyl isocyanide four component condensation afforded in good yield two diastereomeric adducts (6a and 6b), which were separated by column chromatography and deblocked to furnish 2-deoxy-β-D-erythropentofuranosyl R and S-glycines (1a) and (1b). 相似文献
20.
Abstract Glycosylation of methyl 3-O-(2-acetamido-3, 6-di-O-benzyl-2-deoxy-β-D-glucopyranosyl)-2,4,6-tri-O-benzyl-β-D-galactopyranoside (2) with 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide (1), catalyzed by mercuric cyanide, afforded a trisaccharide derivative, which was not separated, but directly O-deacetylated to give methyl 3-O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-β-D-galactopyranosyl-β-D-giucopyranosyl)-2,4,6-tri-O-benzyl-β-D-galactopyranoside (8). Hydrogenolysls of the benzyl groups of 8 then furnished the title trisaccharide (9). A similar pflyccsylation of methyl 3-O-(2-acetamido-3-O-acetyl-2-deoxy-β-D-glucopyranosyl)-2,4,6-tri-O-benzyl- β-D-galactopyranoside (obtained by acetylation of 4, followed by hydrolysis of the benzylidene acetal group) with bromide 1 gave a tribenzyl trisaccharide, which, on catalytic hydrogenolysls, furnished the isomeric trisaccharide (12). Methylation of 4 and 2 with methyl iodide-silver oxide in 1:1 dichloro-methane-N, N-dimethylformamide gave the 3-O- and 4-O-monomethyl ethers (13) and (15), respectively. Hydrogenolysis of the benzyl groups of 13 and 15 then provided the title monomethylated disaechartdes (15) and (16), respectively. The structures of trisacchacides 9 and 12, and disaccharides 14 and 16 were all established by 13C MMR spectroscopy. 相似文献