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1.
The sulfoxide of 6Z-[2-(methoxyimino)propylidene]penicillanic acid tert-butyl ester and the sulfones of 6Z-[2-(hydroxyimino-, methoxyimino-, benzyloxyimino-, 2-bromo- and 4-bromobenzyloxyimino)-propylidene]penicillanic acid in the syn and anti forms have been synthesized by the condensation of the sulfoxide and sulfone of 6Z-acetylmethylenepenicillanic acid tert-butyl ester with hydroxylamine, methoxyamine, benzyloxyamine, 2-bromo- and 4-bromobenzyloxyamines. The syn and anti isomers of 3Z-(2-methoxyiminopropylidene)-4R-(benzothiazolyl-2-dithio)-2-oxoazetidinyl-1R-(2-propenyl)acetic acid tert-butyl ester were obtained by opening of the thiazolidine ring in 6Z-[2-(methoxy-imino)propylidene]-1-oxopenicillanic acid tert-butyl ester with 2-mercaptobenzothiazole. The 3Z-(2-methoxyiminopropylidene)-4R-(methylsulfonyl)-2-oxoazetidinyl-1-(2-propylidene)acetic acid tert-butyl ester was synthesized by the interaction of 1,8-diazobicyclo[5.4.0]undec-7-ene and methyl iodide with 6Z-[2-(methoxyimino)propylidene]-1,1-dioxopenicillanic acid tert-butyl ester. A dependence of the cytotoxic effect in relation to cancer and normal cells in vitro on the structure of the substituent in position 6 and the syn and anti isomerism of the oxyimino group was established for the synthesized compounds.  相似文献   

2.
Irradiation of cis-1,2-dimethyl-1,2-diphenyl-1,2-disilacyclohexane (1a) in the presence of tert-butyl alcohol in hexane with a low-pressure mercury lamp bearing a Vycor filter proceeded with high stereospecificity to give cis-2,3-benzo-1-tert-butoxy-1,4-dimethyl-4-phenyl-1,4-disilacyclooct-2-ene (2a), in 33% isolated yield, together with a 15% yield of 1-[(tert-butoxy)methylphenylsilyl]-4-(methylphenylsilyl)butane (3). The photolysis of trans-1,2-dimethyl-1,2-diphenyl-1,2-disilacyclohexane (1b) with tert-butyl alcohol under the same conditions gave stereospecifically trans-2,3-benzo-1-tert-butoxy-1,4-dimethyl-4-phenyl-1,4-disilacyclooct-2-ene (2b) in 41% isolated yield, along with a 12% yield of 3. Similar photolysis of 1a and 1b with tert-butyl alcohol-d1 produced 2a and 2b, respectively, in addition to 1-[(tert-butoxy)(monodeuteriomethyl)(phenyl)silyl]-4-(methylphenylsilyl)butane. When 1a and 1b were photolyzed with acetone in a hexane solution, cis- and trans-2,3-benzo-1-isopropoxy-1,4-dimethyl-4-phenyl-1,4-disilacyclooct-2-ene (4a and 4b) were obtained in 25% and 23% isolated yield. In both photolyses, 1-(hydroxymethylphenylsilyl)-4-(methylphenylsilyl)butane (5) was also isolated in 4% and 5% yield, respectively. The photolysis of 1a with acetone-d6 under the same conditions gave 4a-d6 and 5-d1 in 18% and 4% yields.  相似文献   

3.
The condensation of the acetylmethylene group in the tert-butyl esters of 7Z-acetylmethylene-3-methyl-3-cephem-4-carboxylic acid and 7Z-acetylmethylene-3-methyl-1,1-dioxo-3-cephem-4-carboxylic acid and in 7Z-acetylmethylene-3-methylene-1,1-dioxo-3-cephem with arylmethoxyamines and O-alkylation of the tert-butyl ester of 7Z-(2-hydroxyimino)propylidene-3-methyl-1,1-dioxo-3-cephem-4-carboxylic acid using substituted benzyl bromides as well as pyridylmethyl chlorides gave arylmethoxyimino and pyridylmethoxyimino derivatives of these compounds in the syn and anti isomeric forms. The Vilsmaier reagent was used to introduce the N,N-dimethylaminomethylene group at C-2 of the cephem system in the tert-butyl esters of 7Z-[2-(arylmethoxyimino)propylidene]-3-methyl-1,1-dioxo-3-cephem-4-carboxylic acid. Subsequent transformation of the N,N-dimethylaminomethylene cephems using hydroxylamine led to 3Z-[2-(anti-arylmethoxyimino)propylidene]-tert-butoxycarbonylmethyl-4-(5-methyl-4-isoxazolylsulfonyl)- azetidin-2-ones. Condensation of the acetyl group in the tert-butyl ester of 7Z-acetylmethylene- 3-methyl-1,1-dioxo-3-cephem-4-carboxylic acid with 4-bromophenylhydrazine gave a cephem with a 2-(4-bromophenylhydrazono)propylidene group at C-7. Acylation of the tert-butyl ester of 7Z-(2-hydroxyimino)propylidene-3-methyl-1,1-dioxo-3-cephem-4-carboxylic acid by 2-bromobenzoyl chloride gave a cephem with a 2-(2-bromo-benzoyloxyimino)propylidene group at C-7. Biological screening of these products towards to malignant and normal cells in vitro showed that their antitumor activity and cytotoxic selectivity towards to malignant and normal cells depend on the structure and configuration of the arylmethoxyimino and pyridylmethoxyimino groups in the 7-alkylidene substituent as well as on the presence or absence of N,N-dimethylaminomethylene and carboxyl groups, respectively, at C-2 and C-4 of the cephem system.  相似文献   

4.
Chlorination of N-aroyl(arylsulfonyl)-2,6-di-tert-butyl-1,4-benzoquinone imines gave Z and E isomers of 4-arylsulfonylimino-2,6-di-tert-butyl-5,6-dichlorocyclohex-2-en-1-ones and Z isomers of 4-aroyl-(arylsulfonyl)imino-2,6-di-tert-butyl-5,5,6-trichlorocyclohex-2-en-1-ones, in which the tert-butyl group on the sp 3-hybridized carbon atom occupies exclusively the axial position. The formation of Z/E-isomeric structures is related to configurational stability of the chlorination products. The chlorination of 4-aroylamino-2,6-di-tertbutylphenols was found to be accompanied by replacement of one tert-butyl group by chlorine atom with formation of 4-aroylimino-6-tert-butyl-2,3,5,6-tetrachlorocyclohex-2-en-1-ones. Original Russian Text ? A.P. Avdeenko, V.V. Pirozhenko, O.V. Shishkin, G.V. Palamarchuk, R.I. Zubatyuk, S.A. Konovalova, O.N. Ludchenko, 2008, published in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 6, pp. 818–824. For communication VII, see [1].  相似文献   

5.
Acyl- and Alkylidenephosphines. XXV. Molecular and Crystal Structure of 1,2-Di(tert-butyl)-3-dimethylamino-1-thio-4-trimethylsilylsulfano-1λ5, 2λ3-diphosphet-3-ene The title compound 1 formed in a nearly quantitative yield by decomposition of tert-butyl(N,N-dimethylthiocarbamoyl)trimethylsilylphosphine, crystallizes in the orthorhombic space group P212121 with {a = 1067.3(1); b = 1077.1(1); c = 1924.6(5) pm; Z = 4} at +20°C. An X-ray structure determination (RG = 0.038) shows two tert-butyl groups at a four- (P1) and a three-coordinate phosphorus atom (P2) to be placed on different sides of the four membered ring. Characteristic bond lengths as well as the angles at the atoms P1, P2, C3, and C4 inside the ring have already been given above.  相似文献   

6.
The regiospecific reaction of 3-benzyloxycarbonylaminomethylcarbonylamino-4-benzoylpyridine (6a) , or 3-t-butoxycarbonylaminomethylcarbonylamino-4-benzoylpyridine (6b) , with either acetyl chloride or ethyl chloroformate, and either n-butylmagnesium chloride or phenylmagnesium bromide afforded the respective 1-acetyl (or ethoxycarbonyl)-2-n-butyl (or phenyl)-3-benzyloxy (or t-butoxy) carbonylaminomethylcarbonylami-no-4-benzoyl-1,2-dihydropyridines 7 in 60-75% yield. Reaction of 1-acetyl (or ethoxycarbonyl)-2-n-butyl (or phenyl)-3-t-butoxycarbonylaminomethylcarbonyl-4-benzoyl-1,2-dihydropyridines 7b, 7f, 7d, 7h with trifluoroacetic acid gave the corresponding 5-phenyl-8-acetyl (or ethoxycarbonyl)-9-n-butyl (or phenyl)-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-ones 8a, 8b, 8c, 8d respectively in 45–63% yield. N1-Methylation of 5-phenyl-8-acetyl-9-n-butyl (or phenyl)-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-ones 8a, 8b using sodium hydride and iodomethane yielded the corresponding N1-methyl derivatives 9a (48%) and 9b (54%). Oxidation of 5,9-diphenyl-8-ethoxycarbonyl-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-one (8d) using p-chloranil afforded 1,3-dihydro-5,9-diphenyl-2H-pyrido[3,4-e]-1,4-diazepin-2-one (10) . 5-Phenyl-8-acetyl-9-n-butyl-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-one (8a) and the corresponding 8-ethoxycarbonyl analog 8c exhibited weak anticonvulsant activity indicating that 8a and 8c may be acting at the same site as the 7-halo-1,4-benzodiazepin-2-one class of compounds.  相似文献   

7.
A synthesis of N-acetylneuraminic acid ( 1 ) and of N-acetyl-4-epineuraminic acid ( 2 , R = H) from 2-acetamido-4,6-O-benzylidene-1,2-dideoxy-1-nitro-D -mannopyranose ( 3 ) and 2-acetamido-1,2-dideoxy-4,6-O-isopropylidene-1-nitro-D -mannopyranose ( 4 ), respectively, is described. Michael addition of 3 and 4 to tert-butyl 2-(bromomethyl)prop-2-enoate ( 5 ) and subsequent hydrolytic removal of the NO2 group gave the 4-nonulosonate tautomers 6 / 7 and 8 / 9 , respectively (Scheme). Stereoselective reduction of 6 / 7 and 8 / 9 with NaBH4/AcOH in dioxane/H2O yielded 12/13 (94:6) and 14/15 (92:8), respectively. Reduction of 6 / 7 and 8 / 9 in the absence of AcOH or in EtOH gave 12 / 13 (15:85) and 14 / 15 (15:85), respectively. Ozonolysis of 12 and 13 followed by hydrolysis gave tert-butyl neuraminate 22 and tert-butyl 4-epineuraminate 24 , respectively. Ozonolysis of 14 / 15 , separation of the products 20 and 21 , and hydrolytic removal of the isopropylidene groups gave 22 and 24 , respectively. The tert-butyl ester 22 was saponified to give 1 , which was further characterized as the methyl ester 23 . Saponification of 24 gave the crude 4-epimer of 1 , which was converted into the stable Na salt 2 and also into the methyl ester 25 .  相似文献   

8.
Acid-catalyzed reaction of 6,10a-dihydroxy-3,4a,7,9-tetra(tert-butyl)-1,2,4a,10a-tetrahydrodibenzo-[b,e][1,4]dioxine-1,2-dione with 2-methylquinoline derivatives led to the formation of a previously unknown system 6-[(Z)-2-(quinolin-2-yl)-1-hydroxyethen-1-yl]pyran-2-one. The molecular structure of 3,5-di(tert-butyl)-6-[(Z)-2-(7,8-dimethyl-4-chloroquinolin-2-yl)-1-hydroxyvinyl]pyran-2-one was established by XRD method; the energy and structural characteristics of its isomers in the gas phase and in a polar solvent were calculated by quantumchemical methods (B3LYP/6-31G**).  相似文献   

9.
The first synthesis of (Z)-neomanoalide ( 4 ) and an improved synthesis of its (E)-isomer 3 was accomplished in a concise, regiocontrolled manner by exploiting 2-[(tert-butyl)dimethylsiloxy]-4{[(tert-butyl)dimethylsiloxy]-methyl}furan ( 6 ) as the key reagent. Lithiation of 6 and subsequent reaction with the (2Z)- or (2E)-isomer of (6E)-3-{[(tert-butyl)dimethylsiloxy]methyl}-7-methyl-9-(2′,6′,6′-trimethylcyclohex-1′-enyl)nona-2,6-dienyl bromide ( 5 ), followed by hydrolysis, afforded the corresponding neomanoalide.  相似文献   

10.
《Tetrahedron letters》2019,60(22):1493-1497
A simple and efficient method was developed for the synthesis of 1,4-thiazin-2-one O-(tert-butyl) oximes and benzo[b][1,4]thiazin-2-one O-(tert-butyl) oximes from N-tert-butoxy acyl imidoyl bromides and 2-aminothiols in the presence of K2CO3/SiO2. Twenty five novel compounds were readily synthesized in excellent yields using this procedure. The products possessed Z-stereochemistry with regard to the CN double bond. The reaction proceeded with initial substitution of bromine in the N-tert-butoxy acyl imidoyl bromides by mercapto groups in the presence of K2CO3/SiO2, and subsequent intramolecular Schiff base formation.  相似文献   

11.
Element-Element Bonds. I. Syntheses and Structure of Tetra(tert-butyl)tetrarsetane and of Tetra(tert-butyl)tetrastibetane Dilithium (tert-butyl)arsenide reacts with (tert-butyl)dichloroarsine to give tetra-(tert-butyl)tetrarsetane 1 ; homologous tetra(tert-butyl)tetrastibetane 2 is formed by reduction of (tert-butyl)dichlorostibane with magnesium. The isotypic compounds 1/2 crystallize in the monoclinic space group P21/c with Z = 4. The dimensions of the unit cells determined at ?45 ± 5°C are: a = 957.4(8)/1 000.2(3); b = 1 399.1(14)/1 423.9(4); c = 1 697.4(9)/1 749.8(7) pm; β = 96.02(6)/96.77(3)°. As shown by low temperature X-ray structure determinations (3 531/3 232 symmetry independent reflections; Rg = 4.0/4.6%) the four membered rings E4 (E = As or Sb) are folded; in all-trans configuration the bulky organic substituents occupy pseudo-equatorial positions. Characteristic averaged bond distances and angles are: E? E 244/282; E? C 202/221 pm; ? E? E? E 86/85° ? E? E? C 101/99°. The dihedral angels of the bisphenoides built up by the atoms of the rings are found to be 139/133°.  相似文献   

12.
Poly[2-(tert-butoxycarbonyl)-1,4-phenylene] ( 2 ) was prepared by the Ni-catalyzed polymerization of tert-butyl 2,5-dichlorobenzoate ( 1 ). The microstructure of polymer 2 was probably alternating head-to-head and tail-to-tail. This polymer was soluble in dipolar aprotic solvents, chloroform, tetrahydrofuran, and dichloromethane. Polymer 2 was saponified easily by thermal or acid treatment to yield poly[2-carboxy-1,4-phenylene] ( 3 ). Decarboxylation of polymer 3 in quinoline in the presence of copper(II) oxide produced poly(p-phenylene) (PPP) ( 4 ).  相似文献   

13.
Acid-catalyzed reaction of 6,10a-dihydroxy-3,4a,7,9-tetra(tert-butyl)-1,2,4a,10a-tetrahydrodibenzo-[b,e][1,4]dioxine-1,2-dione with 4-chloro-2,7,8-trimethylquinoline gave previously unknown 3,6,8-tri-tert-butyl-3-[2-tert-butyl-5-(4-chloro-7,8-dimethylquinolin-2-yl)-4-hydroxy-3-oxopenta-1,4-dien-1-yl]-5-hydroxy-1,4-benzodioxin-2-one whose structure was determined by X-ray analysis. The energy and structure parameters of possible isomers of the product in the gas phase and in solution were estimated by PBE0/6-31G** quantum-chemical calculations.  相似文献   

14.
The Diels-Alder adduct of furan and 1-cyanovinyl (1′R)-camphanate was converted into methyl [(tert-butyl)-dimethylsilyl 5-deoxy-2, 3-O-isopropylidene-β-L -ribo-hexofuranosid] uronate ((+)- 4 ). Reduction with diisobutyl-aluminium hydride gave the corresponding aldehyde which was condensed with the ylide derived from triphenyl-(propyl)phosphonium bromide to give (1R, 2S, 3S, 4S)-1-[(tert-butyl)dimethylsilyloxy]tetrahedro-2, 3-(isopropyl-idenedioxy)-4-[(Z)-pent-2′ -enyl]furan ((+)- 7 ). Removal of the silyl protective group gave a mixture of the corresponding furanose that underwent Wittig reaction with the ylide derived from [8-(methoxycarbonyl)-octyl]triphenylphosphonium bromide to yield methyl (11R, 12S, 13S, 9Z, 15Z)-13-hydroxy-11, 12-(isopropylidene-dioxy)octadeca-9, 15-dienoate ((?)- 9 ). Acidic hydrolysis, then saponification afforded (11R, 12S, 13S, 9Z, 15Z)-11, 12, 13-trihydroxyoctadeca-9, 15-dienoic acid ( 1 ).  相似文献   

15.
Compounds of Germanium and Tin. 3. Sterically Congested Alkylarylstannanes by Transfer and Isomerization of 2,4,6-Tri-tert-butylphenyl Groups Reaction of SnBr4 and SnI4 with 2,4,6-tri-tert-butylphenyllithium (ArLi) by rearrangement of two Ar-groups gives the stannanes ArR2SnBr ( 3 ) and ArR2SnI ( 4 ), R = 2-methyl-2(3,5-di-tert-butylphenyl)propyl, which by a further transalkylation reaction with methyl lithium yield ArR2SnCH3 ( 5 ). However, treatment of 3 and 4 with tert-butyl lithium exclusively leads to ArR2SnH ( 6 ) which surprisingly is also obtained by reaction of ArRSnCl2 with tert-butyl lithium, presumably by an intermolecular R-group transfer. The structures of 5 and 6 were confirmed by X-ray crystallography.  相似文献   

16.
Reaction of Di(tert-butyl)- and Diphenyldiazomethane and 1,3-Thiazole-5(4H)-thiones: Isolation and Crystal Structure of the Primary Cycloadduct Reactions of diazo compounds with C?S bonds proceed via the formation of thiocarbonyl ylides, which, under the reaction conditions, undergo either 1,3-dipolar cycloadditions or electrocyclic ring closer to thiiranes (Scheme 1). With the sterically hindered di(tert-butyl)diazomethane ( 2c ), 1,3-thiazole-5(4H)-thiones 1 react to give spirocyclic 2,5-dihydro-1,3,4-thiadiazoles 3 (Scheme 2). These adducts are stable in solution at ?20°, and they could be isolated in crystalline form. The structure of 3c was established by X-ray crystallography. In CDCl3 solution at room temperature, a cycloreversion occurs, and the adducts of type 3 are in an equilibrium with 1 and 2c . In contrast, the reaction of 1 with diphenyldiazomethane ( 2d ) gave spirocyclic thiiranes 4 as the only product in high yield (Scheme 3). The crystal structure of 4b was also determined by X-ray analysis. The desulfurization of compounds 4 to 4,5-dihydro-5-(diphenylmethylidene)-1,3-thiazoles 5 was achieved by treating 4 with triphenylphosphine in boiling THF. The crystal structure of 5f is shown.  相似文献   

17.
Homogeneous asymmetric hydrogenation of a wide range of methyl and tert-butyl (Z)-2-(acylamino)-3-(heteroaryl)acrylates (see 1a–f and 2a–d, f, g , resp.) catalyzed by diphosphinerhodium catalysts was studied for the synthesis of enantiomerically pure 3-furyl-, 3-thienyl-, and 3-pyrrolylalanines (see 3a–f , and 4a–d, g ; Scheme 1). The precursors, the (Z)-α-amino-α,β-didehydro esters 1a–f and 2a–d, f, g were prepared in high yields using the phosphorylglycine-ester method (Scheme 1). Isomerically pure (Z)-α-amino-α,β-didehydro esters were required to obtain the highest enantiomeric excesses (ee's) in the asymmetric hydrogenation, and the tert-butyl-ester strategy was beneficial in terms of both getting pure (Z)-α-amino-α,β-didehydro esters and obtaining high ee's in the hydrogenation. Finally, in contrast to the methyl-ester series, deprotection of the tert-butyl esters 4a–d, g was easily performed using CF3CO2H without any racemization.  相似文献   

18.
For trans-3-R- and 5-R-1-acetoxy-4-cyanocyclohexene-6,6-d2 the molar fractions of diequatorial conformers are 0.83 (3-methyl), 0.68 (5-methyl), 0.57 (3-tert-butyl) and 0.55–0.69 (5-tert-butyl). For the last two compounds the values of the coupling constants are in agreement with the hypothesis of an ee?aa equilibrium. For the cis isomers, the molar fractions of equatorial alkyl conformers are 0.76 (3-methyl and 5-methyl) and 1.0 (3-tert-butyl and 5-tert-butyl). The cis-1-acetoxy-3-tert-butyl-4-methoxycarbonyl-cyclohexene presents a conformational heterogeneity. The conformational free energy of the methyl group in position 4 has been evaluated as ?0.6 kcal mol?1 (2.5 kJ mol?1).  相似文献   

19.
The one-pot reaction of ethyl 1-cyclopropyl-6,7,8-trifluoro-1,4-dihydro-4-oxoquinoline-3-carboxylate ( 6 ) with tert-butyl acetoacetate gave 3-tert-butyl 7-ethyl 9-cyclopropyl-4-fluoro-6,9-dihydro-2-methyl-6-oxofuro[3,2-h]quinoline-3,7-dicarboxylate ( 5 ). This regioselective cyclization was rationalized by the Hard and Soft Acids and Bases principle. By use of a similar furan-forming reaction, we prepared 2-(amino-methyl)furo[3,2-h]quinoline-7-carboxylic acid 4 . Compound 4 showed weak antibacterial activity.  相似文献   

20.
《Tetrahedron: Asymmetry》2001,12(7):1095-1099
This paper describes asymmetric synthesis of β-aminophenylpropionic acid through application of a homochiral sulfoxide auxiliary. High kinetically controlled (3R,2S,RS)-diastereoselectivity (−60°C) is achieved during addition of the lithium enolate of tert-butyl (+)-(R)-p-toluenesulfinylacetate to substituted N-(benzylidene)toluene-4-sulfonamides 2a2d. The reductive cleavage of adduct 3a with sodium amalgam yielded tert-butyl 3-(toluene-4-sulfonamido)-3-phenylpropionate 5a, which was subjected to ester hydrolysis and subsequent detosylation with sodium in liquid ammonia to yield (S)-β-aminophenylpropionic acid in good yield and high 91% e.e.  相似文献   

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