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1.
The Hantzsch condensation of 2-azidoethyl acetoacetate with 2,3-dichlorobenzaldehyde and isopropyl 3-aminocrotonate afforded 3-(2-azidoethyl) 5-isopropyl 2,6-dimethyl-1,4-dihydro-4-(2,3-dichlorophenyl)pyridine-3,5-dicarboxylate ( 7 ). Reduction of the 3-(2-azidoethyl) moiety of 7 using 5% palladium-on-calcium carbonate and hydrogen gas gave the 3-(2-aminoethyl) derivative 8 , which was subjected to guanylation using 1H-pyrazole-1-carboxamidine hydrochloride to yield the target 3-(2-guanidinoethyl) analog 9 . The 3-(2-aminoethyl) product 8 was elaborated to the title compound 3-[2-(S-methylisothioureidoethyl)] 5-isopropyl 2,6-dimethyl-1,4-dihydro-4-(2,3-dichlorophenyl)pyridine-3,5-dicarboxylate hydrochloride ( 12 ) via the intermediate 3-(2-thioureidoethyl) compound 10 . The 3-(2-guanidinoethyl 9 and 3-[2-(S-methylisothioureidoethyl)] 12 compounds were about 116- and 23-fold less potent calcium channel antagonists, respectively relative to the reference drug nifedipine.  相似文献   

2.
We have recently described a new synthetic route which has been used in our laboratory for the preparation of several novel heterocyclic systems comprising, the I,l-dimethylthiazolidino[3,4-o)piperazine-5,8- dione-3-carboxylic acid and the 2,2-dimethylthiazolidino[3,2-a]piper- azine-5,8-dione-3-carboxylic acid (8). The former was obtained with quan- titative yield and the latter with 71% yield. As a development of our studies on novel 2,5-piperazinedione systems, we describe in this report, the synthesis of the (2,5-dioxopiperazinyl)2-isobutyric acid (9), then-butyl(2-isopropyl)3,6-dioxopiperazinyl-l) acetate (1 l), and another synthetic route, illustrated in Scheme I, by which the compound 8 was obtained with quantitative yield. Spectrometric data were obtained and their interpretation confirms the proposed structure of the new compounds.  相似文献   

3.
13C NMR study of the reaction between 3-isopropyl indene and trifluoromethane sulfonic acid in methylene chloride solution at ?70° shows the presence of 1-isopropyl indanyl cation. Proposed assignments of the chemical shifts show charge delocalisation due to the aromatic ring.  相似文献   

4.
The natural products containing isodaucane skeleton 1 belonged to a rare kind of sesqiterpenes.1 In recent years, investigation on this kind sesquiterpenes have been attracting the interest of chemists, because some isodaucane sesquiterpenes isolated from the medical plants have been shown important bioactivities.2 The main synthetic challenge of isodaucane natural products resided in the introduction of syn-C1-methyl and C8-isopropyl groups. Although some approaches to synthesize isodaucane have been reported to date,3 they needed several steps to construct the cyclopentane unit bearing syn-methyl and isopropyl groups.  相似文献   

5.
Flotation collector O-isopropyl N-ethylthionocarbamate (IPETC) is widely used for separation of sulfide ores. Its removal from water by several oxidation processes was studied. Photocatalytic oxidation with air in the presence of iron salts, utilizing solar irradiation or artificial UV-A light is very efficient. Oxidation leads through the formation of O-isopropyl N-ethylcarbamate and several other reaction intermediates to total decomposition of organic compound in the final stage in 1 day. Similar results were obtained with a Fenton type oxidation with hydrogen peroxide and iron salts. Treatment with sodium hypochlorite yields mainly O-isopropyl N-ethylcarbamate. The formation of this compound in wastewaters can be of concern, since simple alkyl carbamates are cancer suspect agents.  相似文献   

6.
The following carbamate derivatives of cyclodextrins (CDs) were prepared as novel chiral stationary phases for capillary gas chromatography: hexakis(2,6-di-O-pentyl)-α-cyclodextrin hexa(3-n-propyl, 3-isopropyl, and 3-phenylcarbamate), heptakis-(2,6-di-O-pentyl)-β-cyclodextrin hepta(3-n-propyl, 3-isopropyl, and 3-phenylcarbamate), and octakis(2,6-di-O-pentyl)-γ-cyclodextrin octa(3-n-propyl, 3-isopropyl, and 3-isopropyl, and 3-phenylcarbamate). Metal capillary columns coated with these stationary phases resolved many kinds of racemic mixture. In general, they were especially effective towards polar compounds such as free alcohols, amines, and epoxides. The types of sample which were effectively resolved depended on the cavity size of the CD: α-CD derivatives were specifically effective toward compounds having linear alkyl chains, and β-CD derivatives toward compounds with phenyl groups. The results indicate that chiral separation with the cyclodextrin carbamates depends on the formation of inclusion complexes and also on the hydrogen-bonding interactions between the samples and the CD carbamates.  相似文献   

7.
1 INTRODUCTION The applications of alkali metal cyclopentadi- enides or their benzoanellated analogues in organo- metallic and organic syntheses are still the interest of chemists[1–3]. The structures of known indenyl li- thium are the supersandwich or oligomeric indenyl lithium[4], and 2-aminoindenyl lithium[5] was charac- terized by high-resolution X-ray powder diffraction and single-crystal X-ray diffraction, respectively. The trigonal planar structure of TMEDA (tetra-methyl- ethyle…  相似文献   

8.
The title compound {η5:η1-[(2-MeOC6H4)C3H6]C9H6}Li(DME) (DME = 1,2-dimethoxy-ethylene) was synthesized by the treatment of 3-[(2-methoxyphenyl)-isopropyl]-indene with 1 equiv. of n-BuLi followed by the recrystallization from a mixed solution of toluene and DME.The compound crystallizes in orthorhombic system, pace group Pbca with a = 14.5677(3), b = 15.54670(10), c = 18.7498(3) (A), Z = 8, V = 4246.45(11) (A)3, Dc = 1.127 g/cm3 andμ(MoKα) = 0.072 mm- 1. The coordination geometry can be described as a distorted tetrahedron.  相似文献   

9.
Methyl 3-amino-2-methoxy-7-isopropylazulene-l-carboxylate( 8a ) and its 5-isopropyl isomer ( 8b ) were synthesized by reduction of the 3-nitro derivatives ( 7a,b ) with zinc/acetic acid in excellent yields. 7a and 7b were prepared by nitration and methylation of methyl 7-isopropyl-2-hydroxyazulene-l-carboxylate ( 5a ) and methyl 5-isopropyl-2-hydroxyazulene-l-carboxylate ( 5b ), respectively. Diazotization of 8a with sodium nitrite in trifluoroacetic acid at 0 °C gave methyl 5-isopropyl-1,2-azulenequinone-3-carboxylate ( 9a ) in 91% yield. Similar reaction of 8b gave the corresponding methyl 7-isopropyl-1,2-azulenequinone-3-carboxylate ( 9b ) in 93% yield. No evidence for the formation of l-diazo-1,2-azulenequinones was obtained.  相似文献   

10.
A series of 1,1'-biphenyl-2,6-dicarboxylic acid diesters were synthesized and examined for their inhibitory activity on guinea-pig detrusor muscle contraction at electrical field stimulation in vitro. Among them, 6-isopropyl 2-methyl 3-hydroxy-5-methyl-2'-nitro-(1,1'-biphenyl)-2,6-dicarboxylate, FR75513 (8a) was one of the potent compounds (IC50 = 3.3 x 10(-6) g/ml). This compound (8a) exhibited a strong inhibitory activity on detrusor contraction after intravenous administration in anesthetized rats (ID50 = 0.04 mg/kg).  相似文献   

11.
Quinol esters 2b, 2c, and 3b and sulfonamide 4c were investigated as possible precursors to 4-alkylaryloxenium ions, reactive intermediates that have not been previously detected. These compounds exhibit a variety of interesting reactions, but with one possible exception, they do not generate oxenium ions. The 4-isopropyl ester 2b predominantly undergoes ordinary acid- and base-catalyzed ester hydrolysis. The 4-tert-butyl ester 2c decomposes under both acidic and neutral conditions to generate tert-butanol and 1-acetyl-1,4-hydroquinone, 8, apparently by an SN1 mechanism. This is also a minor decomposition pathway for 2b, but the mechanism in that case is not likely to be SN1. Decomposition of 2c in the presence of N3- leads to formation of the explosive 2,3,5,6-tetraazido-1,4-benzoquinone, 14, produced by N3--induced hydrolysis of 8, followed by a series of oxidations and nucleophilic additions by N3-. No products suggestive of N3--trapping of an oxenium ion were detected. The 4-isopropyl dichloroacetic acid ester 3b reacts with N3- to generate the two adducts 2-azido-4-isopropylphenol, 5b, and 3-azido-4-isopropylphenol, 11b. Although 5b is the expected product of N3- trapping of the oxenium ion, kinetic analysis shows that it is produced by a kinetically bimolecular reaction of N3- with 3b. No oxenium ion is involved. The sulfonamide 4c predominantly undergoes a rearrangement reaction under acidic and neutral conditions, but a minor component of the reaction yields 4-tert-butylcresol, 17, and 2-azido-4-tert-butylphenol, 5c, in the presence of N3-. These products may indicate that 4c generates the oxenium ion 1c, but they are generated in very low yields (ca. 10%) so it is not possible to definitively conclude that 1c has been produced. If 1c has been generated, the N3--trapping data indicate that it is a very short-lived and reactive species in H2O. Comparisons with similarly reactive nitrenium ions indicate that the lifetime of 1c is ca. 20-200 ps if it is generated, so it must react by a preassociation process. Density functional theory calculations at the B3LYP/6-31G*//HF/6-31G* level coupled with kinetic correlations also indicate that the aqueous solution lifetimes of 1a-c are in the picosecond range.  相似文献   

12.

4,5-dialkyl 1-isopropyl 3-isopropoxy-1H-pyrazole-1,4,5-tricarboxylate was obtained in an excellent yield from the reaction of dialkyl acetylenedicarboxylates and diisopropyl azodicarboxylate in the presence of triphenylphosphine in dry dichloromethane. This reaction provides a useful synthetic route to highly functionalized pyrazoles.  相似文献   

13.
《Fluid Phase Equilibria》2005,235(1):18-25
Hydrogels are crosslinked macromolecules (polymer networks) with segments of hydrophilic groups. Such polymer networks are able to swell as well as to shrink in liquid phases. This paper reports experimental results for the swelling behavior of a nonionic, synthetic hydrogel of N-isopropyl acrylamide in partially miscible aqueous solutions of a single organic solvent (1-butanol and methyl isobutyl ketone) at 298 K. The experimental results are correlated applying a thermodynamic model, which combines an expression for the Gibbs energy of a liquid phase with an equation for the Helmholtz energy of an elastic network.  相似文献   

14.
Stable tris-, bis- and mono[9-(azuleno[1,2-b]thienyl)]methyl cations (7a, 8a and 9a) and their derivatives, with a 6-isopropyl substituent on each azuleno[1,2-b]thiophene ring (7b, 8b and 9b) were prepared by the hydride abstraction reaction of the corresponding methane derivatives. The bonding situation of these compounds including the methane derivatives was examined by analysis of the 3J(H,H) values for the seven-membered ring from the 1H NMR spectra. The methane derivatives exhibited a significant alternating pattern in the 3J(H,H) values, which indicated that the pi-system of the azulene core is perturbed by the fused thiophene ring, showing a tendency towards a localized heptafulvene substructure. The 3J(H,H) values of 7b and 8b in the seven-membered ring revealed that the alternating C-C bond lengths in the azulene core still existed. The cations 9a and 9b, which exhibited nearly equal 3J(H,H) values in the seven-membered ring, exhibit the development of a delocalized tropylium substructure in the azulene core. X-ray crystal analysis of 6-isopropylazuleno[1,2-b]thiophene revealed substantial bond-length alternation in the seven-membered ring. Significant bond-length equalization in the seven-membered ring was also confirmed by the X-ray crystal analysis of 9b. The stability of these carbocations was examined by measurement of the pKR+ values and the redox potentials, which revealed that the bond-length alternation in the azulene core does not significantly affect the stability of the carbocations.  相似文献   

15.
The 1-isopropyl and 1-benzyl derivatives of 1,5-tetrahydrobenzodiazepin-2-one were synthesized by alkylation under the conditions of phase-transfer catalysis. The inversion of the heterocycle was studied by PMR spectroscopy, and the free energies of activation were determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 254–258, February, 1986.  相似文献   

16.
Reactions of isopropyl 2-(1-aryl-4,5-dioxo-2-phenyl-4,5-dihydro-1H-pyrrol-3-yl)-2-oxoacetates with aromatic amines involve a pyrroledione-pyrroledione recyclization to form isopropyl 1-aryl-2-hydroxy-4,5-dioxo-3-[phenyl(arylamino)methylene]pyrrolidine-2-carboxylates. The crystal and molecular structure of (Z)-isopropyl 2-hydroxy-4,5-dioxo-1-phenyl-3-[phenyl(phenylamino)methylene]pyrrolidine-2-carboxylate was proved by XRD analysis.  相似文献   

17.
Absorbance values between 300 and 800 nm of aqueous solutions of poly(N-isopropyl acrylamide-co-itaconic acid-9.80), poly(N-isopropyl acrylamide-co-itaconic acid-52.05) and poly(N-isopropyl acrylamide)s containing Tegomer H-Si 2111 end groups and/or blocks were measured using a Shimadzu 160-A UV-visible spectrometer. Turbidities obtained from these absorbance values were used to interpret the macromolecular phase transition from a hydrophilic to a hydrophobic structure of the polymers. The effects of comonomer type and content, concentration of the solutions, pH and temperature on the coil-globule transition were discussed in terms of turbidity form factor, β related to size and shapes of particles and calculated by using the simplified form of Debye equation.The results presented in this work show that the presence of Tegomer H-Si 2111 (Si containing end groups and/or blocks) or high amount of itaconic acid (IA) in the chains prevent a collapse transition from hydrated extended coils to hydrophobic globules, which aggregate and form a separate phase (β<2). Furthermore, it was observed that in the case of concentrated solutions intermolecular hydrophobic interactions between isopropyl groups overcame the repulsive forces resulting from the ionized carboxylic acid groups of IA or surface active nature of Si containing hydrophobic groups (β>2). This stage of the transition corresponds to macroscopic phase separation after an intramolecular process.  相似文献   

18.
1-Acetyl-5-hydroxyl-2-isopropyl(phenyl)pyrazolidines, as well as 1-hydroxyperhydropyrazolo[1,2-a]-4H-pyridazine-5,8-dione, react readily with alkyl-, aryl-, and acylhydrazines and hydroxylamine to give the corresponding products of substitution of the OH group, which, depending on the nature of the hydrazine, exist in the linear -hydrazidohydrazone (oxime) form or in the form of a cyclic tautomer, viz., the corresponding 1-acetyl-5-hydrazinopyrazolidine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1238–1241, September, 1985.  相似文献   

19.
A new, practical, and hundred-gram scale synthesis of saflufenacil, a protoporphyrinogen oxidase (PPO) inhibitor herbicide, is described. The key intermediate N-methyl-N-isopropyl sulfamide ( 12 ) is obtained from sulfuryl chloride isocyanate, t-butanol, and N-methyl-N-isopropylamine in 74.8% yield over 3 steps. Saflufenacil is prepared in 48.6% yield over 8 steps and 98.7% purity (HPLC).  相似文献   

20.
《Tetrahedron: Asymmetry》1998,9(23):4275-4284
The substitution of the 4-methyl group by a 4-isopropyl group in the 2-benzyl-2,4-dihydro-1H-pyrazino[2,1-b]quinazoline-3,6-dione system allows a notable improvement in the stereoselective alkylation at C-1. The configuration of the newly introduced stereogenic centre has been assigned on the basis of 1H NMR data and NOE measurements.  相似文献   

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