首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A highly regioselective route was established to 2-aryl-, 2-cyclohexyl-, and 2-(2-arylethyl)4-alkylthiophenes, which are potential candidates as liquid crystalline compounds of low viscosity. The key synthetic intermediates, 2-substituted-4-(chloromethyl)thiophenes 6, 14, and 20 were prepared respectively from the reactions of β, γ-epoxycarbonyl compounds 5, 13, and 19 with Lawesson's reagent in the presence of a catalytic amount of p -toluenesulfonic acid. The epoxycarbonyl compounds were obtained from the TiCl4-mediated reactions of 2-(chloromethyl)-3-(trimethylsliyl)propene (10) with acid chlorides followed by epoxidation with m-chloroperoxybenzoic acid, or from prior epoxidation followed by oxidation with pyridinium dichromate of homoallylic alcohols 3. The homoallylic alcohols 3 were synthesized from the reactions of 2-(chloromethyl)-3-(trichlorosilyl)propene (2) with aldehydes in N, N-dimethylformamide. Copper (I) catalysed cross-coupling reactions of 2-substituted-4-(bromomethyl)thiophenes (which were prepared by transhalogenation of 2-substituted-4- (chloromethyl)thiophenes with NaBr in acetone) with Grignard reagents afforded 2,4-disubstituted thiophenes. Using this method, eleven 2,4-disubstituted thiophenes were synthesized and their potentials as liquid crystalline compound of low viscosity were examined. The synthesized 2-(4-cyanophenyl)-4-pentylthiophene was observed to have a lower melting point than the corresponding 2,5-disubstituted thiophene. This observation is consistent with the expectation from the basis of molecular linearity which can affect the viscosity and/or melting point of crystalline compounds.  相似文献   

2.
The push‐pull activated methyl (3Z)‐4,6‐O‐benzylidene‐3‐[(methylthio)methylene]‐3‐deoxy‐α‐D‐erythro‐hexopyranosid‐2‐ulose (1) reacted with dialkyl malonate in the presence of potassium carbonate to give the alkyl (2R,4aR,6S,10bS)‐4a,6,8,10b‐tetrahydro‐6‐methoxy‐8‐oxo‐2‐phenyl‐4H‐pyrano[3′,2′:4,5]pyrano[3,2‐d][1,3]dioxine‐9‐carboxylates 2 and 3. Treatment of 1 with 3‐oxo‐N‐phenyl‐butyramide, N‐(4‐methoxy‐phenyl)‐3‐oxo‐butyramide, and 3‐oxo‐No‐tolyl‐butyramide, respectively, in the presence of potassium carbonate and 18‐crown‐6 yielded the (2R,4aR,6S,10bS)‐9‐acetyl‐7‐aryl‐4,4a,7,10b‐tetrahydro‐6‐methoxy‐2‐phenyl[1,3]dioxino‐[4′,5′:5,6]pyrano[3,4‐b]pyridin‐8(6H)‐ones 46. (2R,4aR,6S,10bS)‐4,4a,8,10b‐Tetrahydro‐6‐methoxy‐8‐oxo‐2‐phenyl‐4H‐pyrano[3′,2′:4,5]pyrano[3,2‐d][1,3]dioxine‐9‐carboxamide (7) was prepared by anellation reactions of 1 either with malononitrile or with cyanoacetamide.  相似文献   

3.
N-[4-(7-Methoxy-4-methyl-2-oxo-2H-chromen-8-yl)-thiazol-2-yl]-guanidine ( 2 ) has been prepared by the condensation of 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin ( 1 ) with guanylthiourea. 4-Methyl-7-methoxy-8-[2-(N′-(1-phenyl-ethylideneisopropylidene)-hydrazino]-thiazol-4-yl]chromen-2-ones ( 3 , 4 , and 5 ) have been prepared by reaction of 4-methyl-7-methoxy-8-(2-bromoacetyl) coumarin ( 1 ) and thiosemicarbazide in presence of acetophenone or acetone without any solvent. The formation of these compounds was further confirmed by the condensation of acetophenone/acetone thiosemicarbazones with 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin ( 1 ) in anhydrous ethanol in a two-step process. Similarly 8-[2-[N′-(benzylidene)hydrazine]-thiazol-4-yl]-7-methoxy-4-methyl-chromen-2-ones ( 6 , 7 , and 8 ) have been prepared by the condensation of 4-methyl-7-methoxy-8-(2-bromoacetyl)chromen-2-one with thiosemicarbazide and various aromatic aldehydes in a single step without any solvent. The formation of these compounds was further confirmed by the condensation of appropriately substituted benzaldehyde thiosemicarbazones with 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin in anhydrous ethanol. 4-Methyl-7-methoxy-8-(2-bromoacetyl) chromen-2-one (1) upon condensation with 3,5-dimercapto-4-amino-s-triazole in anhydrous ethanol resulted in the formation of 8-(3-mercapto-3H-[1,2,4]triazolo[3,4-b]thiadiazin-6-yl)-7-methoxy-4-methyl chromen-2-one (9). This compound ( 9 ) on reaction with various alkyl and phenacyl halides in anhydrous ethanol gave corresponding 4-methyl-7-methoxy-8-[3-(2-oxo-substituted sulphanyl)-7H-[1,2,4]triazolo[3,4-b]thiadiazin-6-yl]chromen-2-ones ( 10 to 18 ). The structures of newly prepared compounds have been confirmed from analytical and spectral data.  相似文献   

4.
α-(1→3)-Linked mannohexaose and mannooctaose as their methyl glycosides were synthesized from condensation of the corresponding α-(1→3)-linked di- (9) and tetrasaccharide donor (21) with the tetrasaccharide acceptor (23), respectively, followed by deacylation. The donor 21 and acceptor 23 were prepared readily from activation of C-1 of the tetrasaccharide 20 and deallylation of the tetrasaccharide 22, respectively. The tetrasaccharide 20 was prepared from oxidative cleavage of 1-O-p-methoxyphenyl of 19, which was obtained from coupling of 9 with 11. The tetrasaccharide 22 was obtained from condensation of the donor 13 with the acceptor 18. These disaccharides 9, 11, 13, and 18 were produced easily by simple chemical transformation using p-methoxyphenyl 3-O-allyl-α-d-mannopyranoside (1) and 2,3,4,6-tetra-O-benzoyl-α-d-mannopyranosyl trichloroacetimidate (6), and methyl 3-O-allyl-α-d-mannopyranoside (14) as the synthons.  相似文献   

5.
The neutral distorted octahedral complexes [ReOCl(L)] {H2L = N,N-bis(2-hydroxybenzyl)-2-(2-aminoethyl)dimethylamine (H2had); N,N-bis(2-hydroxybenzyl)-aminomethylpyridine (H2hap); N,N-bis(2-hydroxybenzyl)-2-(2-aminoethyl)pyridine (H2hae)} were prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H2L in ethanol. X-ray structure determinations of [ReOCl(had)] (1) and [ReOCl(hap)] (2) were performed, and the structures compared. In both complexes the choride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen.  相似文献   

6.
Some novel pyrazolo[1,5-α]pyrimidines 5a-f, 10a,b, 1,2,4-triazolo[1.5-α]-pyrimidine (12), and pyrimido[1,2-α]benzimidazole 18 could be synthesized by reacting 3-(4-chlorophenyl)-2-(N,N-dimethylamino)methylene-3-oxopropanenitrile (2) with 5-amino-3- and/or 4-substituted-1H-pyrazoles 3a-f and 9a,b, 3-amino-1,2,4-triazole (11) and 2-aminobenzimidazole (14), respectively. The reaction of 2 with 1H-benzimidazol-2-ylacetonitrile (19) afforded the pyrido[1,2-α]benzimidazole 20. On the other hand, the reaction of 2 with guanidine, hydrazine, and phenyl hydrazine afforded the pyrimidine 24, and the pyrazoles 27, 28, respectively. However, the reaction of 2 with hydroxyl amine did not afford the isoxazole 32.  相似文献   

7.
ABSTRACT

3-O-Sulfo glucuronyl paragloboside derivatives (pentasaccharides) have been synthesized. The important intermediate designed for a facile sulfation in the last step and effective, stereocontrolled glycosidation, methyl (4-O-acetyl-2-O-benzoyl-3-O-levulinoyl-α-D-glucopyranosyl trichloroacetimidate)uronate (8) was prepared from methyl [2-(trimethylsilyl)ethyl β-D-glucopyranosid]uronate (3) via selective 4-O-acetylation, 2-O-benzoylation, 3-O-levulinoylation, removal of the 2-(trimethylsilyl)ethyl group and imidate formation. The glycosylation of 8 with 2-(trimethylsilyl)ethyl 2,4,6-tri-O-benzyl-β-D-galactopyranoside (9) using trimethylsilyl trifluoromethanesulfonate gave 2-(trimethylsilyl)ethyl O-(methyl 4-O-acetyl-2-O-benzoyl-3-O-levulinoyl-β-D-glucopyranosyluronate)-(1→3)-2,4,6-tri-O-benzyl-β-D-galactopyranoside (10), which was transformed via removal of the benzyl group, benzoylation, removal of the 2-(trimethylsilyl)ethyl group and imidate formation into the disaccharide donor 13. On the other hand, 2-(trimethylsilyl)ethyl O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranosyl)-(1→3)-O-(2,4,6-tri-O-benzyl-β-D-galactopyranosyl)-(1→4)-2,3,6-tri-O-benzyl-β-D-glucopyranoside (20) as the acceptor was prepared from 2-(trimethylsilyl)ethyl 3,6-di-O-benzyl-2-deoxy-2-phthalimido-β-D-glucopyranoside (14) via O-acetylation, removal of the 2-(trimethylsilyl)ethyl group, imidate formation, coupling with 2-(trimethylsilyl)ethyl O-(2,4,6-tri-O-benzyl-β-D-galactopyranosyl)-(1→4)-2,3,6-tri-O-benzyl-β-D-glucopyranoside (18), removal of the O-acetyl and N-phthaloyl group followed by N-acetylation. Condensation of 13 with 20 using trimethylsilyl trifluoromethanesulfonate afforded the desired pentasaccharide 21, which was transformed by removal of the benzyl group, O-acetylation, removal of the 2-(trimethylsilyl)ethyl group and imidate formation into the pentasaccharide donor 24. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol (25) with 24 gave the desired β-glycoside 26, which was transformed into the four target compounds, via reduction of the azido group, coupling with octadecanoic acid or tetracosanoic acid, selective removal of the levulinoyl group, O-sulfation, hydrolysis of the methyl ester group and O-deacylation.  相似文献   

8.
《合成通讯》2013,43(13):1961-1975
ABSTRACT

The new anthracycline analogues (2–10) as potential anticancer agents were synthesized from daunomycin (1a) and doxorubicin (1b). Compounds 2, 6, and 7 were prepared by the nucleophilic displacement type esterification of a 14-bromodaunomycin (1c) with a sodium pyruvate, aspartate, and N-acetylaspartic acid, respectively. Whereas compounds (3, 8) and (4, 9) were prepared by the reaction of daunomycin (1a) or doxorubicin (1b) with one equivalent of the corresponding acids in the presence of EDCI/PP, compounds (5, 10) were obtained from 1b by reaction with two equivalents of the corresponding acids in the same manner.  相似文献   

9.
Abstract

Five sialyl Lew is X ganglioside analogs containing 4-(2-tetradecylhexadecanoylamino)benzyl group in place of ceramide and a variety of lengths of ethylene glycol chains as the spacer, have been synthesized. Glycosidation of O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-α-D-glacto-2-nonulopyranosylonate)-(2→3)-O-(4-O-acetyl-2,6-di-O-benzoyl-β-D-galactopyranosyl)-(1→4)-O-[(2,3,4-tri-O-acetylα-L-fucopyranosyl)-(1→3)]-2,4-di-O-benzoyl-α-D-glucopyranosyl trichloroacetimidate (13) with oligo ethyleneglycol monobenzyl ether derivatives 9, 10, 11 and 12, prepared from the corresponding oligo ethyleneglycols by 4-nitrobenzylation, reduction and N-acylation with 2-tetradecylhexadecanoic acid, using boron trifluoride etherate gave the corresponding glycolipid derivatives 14, 15, 16 and 17. A similar glycosidation of 13 with 4-nitrobenzyl alcohol gave the 4-nitrobenzyl glycoside 18, which was converted via reduction of nitro group and N-acylation into the corresponding glycolipid derivative 19. Compounds 14-17 and 19 were transformed into the title compounds by O-deacylation and hydrolysis of methyl ester group in good yields.

  相似文献   

10.
New substituted anilides of the heterocyclic series 2, 4, 5, 6, 7 together with the earlier described compounds 1 and 3 (Jarak I et al. (2005) J Med Chem 48:2346), were synthesized from the corresponding heterocyclic carbonyl chlorides, methoxycarbonyl- and cyano-substituted anilines. Compounds 2 and 7 were prepared by methylation with methyl-iodide on the amide and the pyridine nitrogen. The Pinner reaction was used in the preparations of amidino-substituted compounds. It seems that all the prepared compounds could be biologically interesting, especially amidino-substituted anilides prepared in the form of water-soluble hydrochlorides or hydroiodides. Molecular and crystal structures of the three compounds, namely, 4′-methoxycarbonyl-N-phenyl-3-chlorobenzo[b]thiophene-2-carboxamide (1), N-(4′-amidinophenyl)-3-chlorobenzo[b]thiophene-2-carboxamide hydrochloride monohydrate (4) and 1-methyl-N-(4-amidinophenyl)-3-pyridine carboxamide iodide hydroiodide (7) have been determined by X-ray single-crystal diffractometry in the solid state. Compounds 1, 4 and 7 are not planar and the amide group (C=O in relation to NH group) is in trans position in all three compounds. The 3-chlorobenzo[b]thiophene moiety in 1 and 4 is oriented with the chloro substituent in cis position in relation to amide NH group. The conformational characteristics of the compounds result from the introduction of different substituents or solvent molecules (water molecule in 4), which leads to various intermolecular hydrogen bonds formation (N–H⋯O, N–H⋯Cl, O–H⋯Cl, N–H⋯I) in 1, 4 and 7. Hydrogen bond formation could be responsible for the potential biological activity of the compounds.  相似文献   

11.
The high specific activity tritiation of (+)-SKF-10,047 (1) and N,N-dimethyltryptamine (4) is described. [N-allyl-3H] (+)-SKF-10,047 (3) was prepared by Lindlar catalyst tritiation of (+)-N-propargylnormetazocine (2) and [N-methyl-3H] N,N-dimethyltryptamine (6) was synthesized by the alkylation of N-methyltryptamine (5) with [3H] methyl iodide. Both sigma-1 synthetic agonist 3 and endogenous agonist 6 have been useful in studying this receptor.  相似文献   

12.
N-(Dimethylfluorosilylmethyl)succinimide (2a) and N-(dimethylfluorosilylmethyl)phthalimide (2b) were synthesized by the Si—N bond cleavage in readily accessible N-(dimethylimidosilylmethyl)imides with BF3 etherate. Analogously, (O→Si)-chelated 1-(dimethylfluorosilylmethyl)-2-pyrrolidone was prepared from 1-(dimethylmorpholinosilylmethyl)-2-pyrrolidone. X-ray diffraction study demonstrated that the silicon atom in the crystals of 2b is pentacoordinated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 558–561, March, 2006.  相似文献   

13.
Phthalazinone and pyridopyridazinone derivatives 3, 5, and 9 were prepared via reaction ofappropriate lactams 2 and 8 with 2-bromoethylphthalimide, N-tosylaziridine, and N,O-ditosyl derivatives of N-methylethanolamine in a two-step process in the presence of MeONa/MeOH or NaH/dimethylformamide (DMF). Starting compounds 2 and 8 were obtained by reaction of hydrazine hydrate with isoindolinones 1 or azaisoindolinones 6. Selected N-(2-phthalimidoethyl)-phthalazinones were converted into corresponding 2-[2-(methylamino) ethyl]- derivatives in satisfactory yields by treatment with hydrazine.  相似文献   

14.
The synthesis and reactions of methyl 2-[3-(trifluoromethyl)phenyl]-4H-furo[3,2-b]pyrrole-5-carboxylate (1a) are described. Upon reaction with methyl iodide, benzyl chloride, or acetic anhydride, this compound gave N-substituted products 1b-d. By hydrolysis of compounds 1a-c, the corresponding acids 2a-c were formed, or by reaction with hydrazine-hydrate, the corresponding carbohydrazides 3a-c were formed. By heating 2-[3-(trifluoromethyl)phenly]-4H-furo[3,2-b]pyrrole-5-carboxylic acid (2a) in acetic anhydride, 4-acetyl-2-[3-(trifluoromethyl)phenyl]furo[3,2-b]pyrrole (4) was formed. By hydrolysis of 4, 2-[3-(trifluoromethyl)phenyl]-4H-furo[3,2-b]pyrrole (5a) was formed, and reactions with methyl iodide or benzyl chloride gave N-substituted products 5b-c. The reaction of 4 with dimethyl butynedioate gave substituted benzo[b]furan 6. Compound 3a reacted with triethyl orthoesters giving 7a-c, which afforded with phosphorus (V) sulphide the corresponding thiones 8a-c. The thiones 8a-c reacted with hydrazine hydrate to form hydrazine derivatives 9a-c. The reaction of triethyl orthoformiate with compounds 9a-c led to furo[2′,3′: 4,5]pyrrolo[1,2-d][1,2,4]triazolo[3,4-f][1,2,4]triazines 10a-c. Hydrazones 11a-c were formed from 3a-c and 5-[3-(trifluoromethyl)phenyl]furan-2-carboxaldehyde. The effect of microwave irradiation on some condensation reactions was compared with “classical” conditions. The results showed that microwave irradiation shortens the reaction time while affording comparable yields.  相似文献   

15.
Methyldithiocarbonyl derivative 2 of pyrazine-2-carboxylic acid N′-methyl-hydrazide 1 was synthesized by methylation of CS2 adduct. Benzylamine caused the decomposition of compound 2 to pyrazine-2-carboxylic acid benzylamide 5 and 1,3-dibenzylthiourea 6. N-methyl-N′-(pyrazine-2-carbonyl)-hydrazinecarbodithioic acid methyl ester 2 were evidenced to cyclize to 3-methyl-5-pyrazin-2-yl-3H-[1, 3, 4]oxadiazole-2-thione 8 in the presence of triethylamine. In the reactions with secondary amines such as morpholine, pyrrolidine and phenylpiperazine pyrazinoyl derivatives (9–11) of thiosemicarbazide were obtained. Hydrazine, methylhydrazine, aminoalcohols, and N-alkylamino-substituted cyclic amines reacted with cyclization to 4-substituted 1,2,4-triazole-3-thiones 12, 13, and 18–22. Synthesized compounds exhibited low tuberculostatic activity in vitro (MIC 50–100 μg/mL).  相似文献   

16.
(Z)-1,6-Anhydro-3-deoxy-4-methylsulfanyl-3-[(methylsulfanyl)methylene]-β-D-erythro-hexopyranos-2-ulose (1) reacted with diethyl malonate, 1,3-diketones, N-aryl-3-oxobutyramides and dialkyl 3-oxoglutarate, respectively, in the presence of potassium carbonate and crown ether to yield diethyl 2-(1,6-anhydro-4-methylsulfanyl—D-arabino-hex-2-ulopyranos-3-ylmethylene) malonate (2), 1-{(1R,2S,8S,9R)-2-hydroxy-4-methyl-8-methylthio-3,11,12- trioxatricyclo7.2.1.02,7dodeca-4,6-dien-5-yl} ethanone (3), (1R,2S,12S,13R)-2-hydroxy-12-methylthio-3,15,16-trioxatetracyclo[11.2.1. 02,11. 04,9] hexadeca- 4(9),10-dien-8-one (4), (1R,8S,9R)-5-acetyl-3-aryl-8-methylthio-11,12-dioxa- 3-azatricyclo-[7.2.1.02,7]dodeca-2(7),5-dien-4-ones (5,6) and dialkyl (1R,8S,-9R)-4-hydroxy-8-methylthio-11,12-dioxatricyclo[7.2.1.02,7]dodeca-2(7),3,5-triene-3,5-dicarboxylates (7,8), respectively.  相似文献   

17.
Synthesis of N-Methyl- and N,N-Dimethylmerucathine and of N-Methyl- and N,N--Dimethylpseudomerucathine Starting from L -Alanine Starting form L -alanine, N-methylmerucathine (= (3R,4S)-4-(methylamino)1-phenyl-1-penten-3-ol; (3R,4S,)- 6 ), N,N-dimethylmerucathine (= (3R,4S)-4-(dimethylamino)-1-phenyl-1-penten-3-ol; (3R,4S)- 9 ), N-methylpseudomerucathine (= (3S,4S)-4-(methylamino)-1-phenyl-1-penten-3-01; (3S,4S)-6), and N,N-dimethylpseudomerucathine (= (3S,4S)-4-(dimethylamino)-1-phenyl-1-penten-3-ol; (3S,4S)- 9 ) were synthesized. The four compounds were analyzed by HPLC and compared with a natural khat extract.  相似文献   

18.
The base-catalyzed reaction of cycloalkanone oximes (la,b) with perfluoro-2-methyl-2-pentene (PFMP) initially affords the addition products,i.e., fluoroalkyl ethers (2a,b). In the presence of KOH, the latter undergoes dehydrofluorination to give perfluoroalkenyl ethers (3a,b). Thermolysis of ethers3a,b results in compounds of two types — pyrrolines (4a,b) andN-perfluoroalkenyl lactams (5a,b). The latter are also prepared from PFMP and the corresponding lactams. The structure ofN-[perfluoro-(2-methyl-2-penten-3-yl)]-2-pyrrolidone (5c) was established by X-ray diffraction study.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1073–1077, June, 1994.  相似文献   

19.
Abstract

Ganglioside GM4 and GM3 analogs, containing 3-deoxy-D-glycero-D-galacto-2-nonulopyranosonic acid (KDN) in place of N-acetylneuraminic acid, have been synthesized. KDN, prepared by the condensation of oxalacetic acid with D-mannose, was converted into methyl (phenyl 4,5,7,8,9-penta-O-acetyl-3-deoxy-2-thio-D-glycero-D-galacto-2-nonulopyranosid)onate (2) via methyl esterification, O-acetylation and replacement of the anomeric acetoxy group with phenyl thio. Glycosylation of 2 with 2-(trimethylsilyl)ethyl 6-O-benzoyl-β-D-galactopyranoside (3) or 2-(trimethylsilyl)ethyl O-(6-O-benzoyl-β-D-galactopyranosyl)-(1→4)-2,6-di-O-benzoyl-β-D-glucopyranoside (4) was performed, using N-iodosuccinimide-trimethylsilyl trifluoromethanesulfonate as the glycosyl promoter, to give 2-(trimethylsilyl)ethyl O-(methyl 4,5,7,8,9-penta-O-acetyl-3-deoxy-D-glycero-α-D-galacto-2-nonulopyranosylonate)-(2→3)-6-O-benzoyl-β-D-galacto-pyranoside (5) and 2-(trimethylsilyl)ethyl O-(methyl 4,5,7,8,9-penta-O-acetyl-3-deoxy-D-glycero-α-D-galacto-2-nonulopyranosylonate)-(2→3)-(6-O-benzoyl-β-D-galactopyrano-syl)-(l→4)-(2,6-di-O-benzoyl-β-D-glucopyranoside (9), respectively. Compounds 5 and 9 were converted via O-acetylation, selective removal of the 2-(trimethylsilyl)ethyl group and subsequent imidate formation, into the corresponding trichloroacetimidates 8 and 12, respectively. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-l,3-diol (13) with 8 and 12 in the presence of boron trifluoride etherate afforded the expected β-glycosides 14 and 17, which were transformed via selective reduction of the azido group, coupling with octadecanoic acid, O-deacylation and de-esterification, into the target gangliosides 16 and 19 in high yields.  相似文献   

20.
The ortho-metalated complex [Pd(x){κ 2 (C,N)-[C6H4CH2NRR′ (Y)}] (2a4a and 2b3b) was prepared by refluxing in benzene equimolecular amounts of Pd(OAc)2 and secondary benzylamine [a, EtNHCH2Ph; b, t-BuNHCH2Ph followed by addition of excess NaCl. The reaction of the complexes [Pd(x){κ 2 (C,N)-[C6H4CH2NRR′ (Y)}] (2a4a and 2b3b) with a stoichiometric amount of Ph3P=C(H)COC6H4-4-Z (Z = Br, Ph) (ZBPPY) (1:1 molar ratio), in THF at low temperature, gives the cationic derivatives [Pd(OC(Z-4-C6H4C=CHPPh3){κ 2 (C,N)-[C6H4CH2NRR′(Y)}] (5a9a, 4b6b, and 4b′6b′), in which the ylide ligand is O-coordinated to the Pd(II) center and trans to the ortho-metalated C(6)H(4) group, in an “end-on carbonyl”. Ortho-metallation, ylide O-coordination, and C-coordination in complexes (5a9a, 4b6b, and 4b′6b′) were characterized by elemental analysis as well as various spectroscopic techniques.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号