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1.
By the reaction of anthranilic hydrazide 1 with cis-2-( p-methylbenzoyl)-1-cyclohexanecarboxylic acid 2a or diendo-3-( p-methylbenzoyl)bicyclo[2.2.1]heptane-2-carboxylic acid 2b , fused tetra- and pentacyclic ring systems 3a, b were prepared, trans-2-Amino-1-cyclohexanecar-bohydrazide 4b was reacted with 3-( p-chlorobenzoyl)propionic acid 5 to yield the pyridazino[6,1- b]quinazolinone 6 . From the reaction of cis-2-amino-1-cyclohexanecarbohydrazide 4a with 2a , three isomeric partially saturated 8 H-phthalazino[1,2- b]quinazolin-8-ones 7a-c were formed. The reaction of diexo-2-aminobicyclo[2.2.1]heptane-3-carbohydrazide 4c and 2a furnished the pentacyclic derivatives 8 and 9 containing a 3-aryl-4,5-dihydropyridazine or 3-arylhexahydropyridazine ring C with cis annelated C/D rings. The formation of 8 and 9 involving different ring systems can be rationalized by two reaction pathways: (i) in the bislactam 9 the carboxyl group acylates the hydrazide, while (ii) in 8 it forms a pyridazine ring with the cyclic amino group by cyclocondensation. The structures of the products were elucidated by 1H and 13C nmr methods, including DEPT, DNOE and 2D-HSC measurements. 相似文献
2.
Direct reversed-phase high-performance liquid chromatographic methods were developed for the separation of the enantiomers of tricyclic β-lactams, cis-3,4-benzo-6-azabicyclo[3.2.0]heptan-7-one, cis-4,5-benzo-7-azabicyclo[4.2.0]-octan-8-one, cis-5,6-benzo-8-azabicyclo[5.2.0]nonan-9-one and new bicyclic β-amino acids, the six- and seven-membered homologues of cis-1-amino-4,5-benzocyclopentane-2-carboxylic acid (benzocispentacin), cis-1-amino-5,6-benzocyclohexane-2-carboxylic acid and cis-1-amino-6,7-benzocycloheptane-2-carboxylic acid. The direct separations of the analytes were performed on chiral stationary phase (CSP) columns containing the macrocyclic glycopeptide antibiotic teicoplanin (Chirobiotic T), teicoplanin aglycone (Chirobiotic TAG), vancomycin (Chirobiotic V), vancomycin aglycone (Chirobiotic VAG), ristocetin A (Chirobiotic R) or a new dimethylphenyl carbamate-derivatized β-cyclodextrin-based Cyclobond DMP. The results achieved with the different methods were compared in systematic chromatographic examinations. The effects of an organic modifier and of the mobile phase composition on the separation and the separation efficiency of different columns were investigated. The difference in enantioselective free energy between the aglycone CSP and the teicoplanin CSP for these β-lactams and β-amino acids ranged between 0.3 and −1.1 kJmol−1. Better enantioseparations were attained in most cases on the aglycone CSP. 相似文献
3.
Summary. All-endo-3-amino-5-hydroxybicyclo[2.2.1]heptane-2-carboxylic acid and two epimers of 3-amino-6-hydroxybicyclo[2.2.1]heptane-2-carboxylic
acid were prepared via 1,3-oxazine or γ-lactone intermediates by the stereoselective functionalization of endo-3-aminobicyclo[2.2.1]hept-5-ene-2-carboxylic acid derivatives. Their structures were proved by IR and NMR spectroscopy, with
the use of HMQC, HMBC, DEPT, and DIFFN OE techniques. 相似文献
4.
All-endo-3-amino-5-hydroxybicyclo[2.2.1]heptane-2-carboxylic acid and two epimers of 3-amino-6-hydroxybicyclo[2.2.1]heptane-2-carboxylic
acid were prepared via 1,3-oxazine or γ-lactone intermediates by the stereoselective functionalization of endo-3-aminobicyclo[2.2.1]hept-5-ene-2-carboxylic acid derivatives. Their structures were proved by IR and NMR spectroscopy, with
the use of HMQC, HMBC, DEPT, and DIFFN OE techniques. 相似文献
5.
Reductive tetraallylation of pyridine-3-and pyridine-4-carboxylic acids with triallylborane in the presence of propan-2-ol
proceeded stereoselectively to yield trans-2,6-diallyl-3- and trans-2,6-diallyl-4-(1-allyl-1-hydroxybut-3-en-1-yl)-1,2,5,6-tetrahydropyridines, respectively. Under the same conditions, the
reaction with pyridine-2-carboxylic acid gave a mixture of trans- and cis-2,6-diallyl-2-(1-allyl-1-hydroxybut-3-en-1-yl)-1,2,5,6-tetrahydropyridines in a ratio of 57:43. When 2,6-diphenylpyridine-4-carboxylic
acid reacted with triallylborane, only the carboxylic group underwent reductive diallylation. When heated with triallylborane
in o-xylene (130–133°C, 7 h), trans-2,6-diallyl-4-(1-allyl-1-hydroxybut-3-en-1-yl)-1,2,3,6-tetrahydropyridine was converted to the corresponding cis-isomer. The stereochemistry of trans-2,6-diallyl-3-(1-allyl-1-hydroxybut-3-en-1-yl)-1,2,5,6,-tetrahydropyridine was confirmed by X-ray diffraction analysis.
Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2320–2326, November, 1998. 相似文献
6.
A rapid reversed-phase high-performance liquid chromatographic procedure is developed and validated for the resolution of
the cis-isomer of 1-[[ p-[2-(3-ethyl-4-methyl-2-oxo-3-pyrroline-1-carboxamido) ethyl] phenyl] sulfonyl]-3-( trans-4-methylcyclohexyl) urea, a dopamine agonist in bulk drugs. The cis-isomer and glimepiride were baseline resolved on a Waters Symmetry column (50 × 4.6 mm, 3.5 μm) using a mobile phase system
containing water: tetrahydrofuran (75:25; v/v. The chromatographic resolutions between cis-isomer and glimepiride were found to be greater than two. The developed method was extensively validated and proved to be
robust. The limit of detection and the limit of quantification of cis-isomer were 500 and 1,500 ng mL −1, respectively, for 10 μL injection volume. The percentage recovery of the cis-isomer ranged from 97.3 to 102.0 in bulk drug samples of glimepiride. Glimepiride sample solution and mobile phase were found
to be stable for at least 48 h. The proposed method was found to be suitable and accurate for the quantitative determination
of the cis-isomer in bulk drugs. 相似文献
7.
A general method for the synthesis of 5-substituted indolizidines based on intramolecular cyclization of trans- and cis-2-allyl-6-R-1,2,3,6-tetrahydropyridines, obtained from pyridine and triallylborane, has been elaborated. The closure of the
five-membered ring is carried out by hydroboration-oxidation followed by cyclization of the resulting δ-amino alcohols in
the presence of the Ph 3P−CBr 4−Et 3N system. (Pr 2BH) 2 and Pr 3B are used as the hydroborating reagents, and H 2O 2 in an acid medium is used for the oxidation of 2-[3-(dipropylboryl]-Δ 2-piperideines formed. This method has been used for the synthesis of two natural alkaloids: indolizidine 209D ( cis-5-hexylindolizidine) and its trans-isomer were prepared from cis- and trans-2-allyl-6-hexyl-1,2,3,6-tetrahydropiridine, respectively; indolizidine 167B and trans-5-propylindolizidine were synthesized from cis- and trans-2,6-diallyl-1,2,3,6-tetra-hydropyridine, respectively.
Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 971–979, May, 1998. 相似文献
8.
This work describes a substrate‐directed fluorination of some highly functionalized cyclopentane derivatives. The cyclic products incorporating CH 2F or CHF 2 moieties in their structure have been synthesized from diexo‐ or diendo‐norbornene β‐amino acids following a stereocontrolled strategy. The synthetic study was based on an oxidative transformation of the ring carbon–carbon double bond of the norbornene β‐amino acids, followed by transformation of the resulted ? all cis“ and ? trans“ diformyl intermediates by fluorination with ?chemodifferentiation“. 相似文献
9.
Summary The synthesis of the complex [Ru(cyclam)Cl 2]Cl (cyclam=1,4,8,11-tetraazacyclotetradecane) has been monitored by reversed-phase high-performance liquid chromatography.
The analytical results obtained during the reaction have shown that it is feasible to identify and isolate the two isomers cis- and trans- [Ru(cyclam)-Cl 2]Cl. The use of an octadecylsiloxy preparative column enabled the separation and purification of these two isomers and the
compounds have been obtained in high purity. The use of reversed-phase high-performance liquid chromatography has afforded
complete analytical control of the syntheses of saturated nitrogendonor macrocyclic complexes of ruthenium, enabling identification
of the cis and trans isomers of the complex [Ru(cyclam)Cl 2]Cl. 相似文献
10.
We describe here a novel strategy for the isolation of antibodies with sequence-specific protease activity: the synthesis
of dipeptide haptens in which the targeted peptide bond has been replaced by a ring-strained or torsionally strained hydroxyethylene
transition-state analog. Thus, the analogs mimic both a peptide bond in a distorted, reactive conformation and the transition
state for peptide bond hydrolysis. In order to obtain sequence-specific antibody proteases, these analogs have been flanked
with additional amino acid residues in preparation for immunization. In particular, we have synthesized peptides containing
analogs such as 2- cis-amino-3- cis-hydroxycyclobutane carboxylic acid and endo-(3-amino-2-hydroxy)bicyclo[2.2.1]heptane-7-anti-carboxylic acid. We have also prepared a series of peptide derivatives containing
analogs, such as 2-[3-amino-2-oxo-1-azetidinyl]-3-methylbutanoic acid, in which the targeted peptide bond has been incorporated
into a β-lactam ring. Since the “peptide bond” has been left intact, these species mimic only a distorted ground state. At
present, antibodies are being elicited against a number of the above peptide derivatives. 相似文献
11.
Summary The synthesis of the complex [Ru(cyclam)Cl 2]Cl (cyclam=1,4,8,11-tetraazacyclotetradecane) has been monitored by reversed-phase high-performance liquid chromatography.
The analytical results obtained during the reaction have shown that it is feasible to identify and isolate the two isomers cis- and trans- [Ru(cyclam)Cl 2]Cl. The use of an octadecylsiloxy preparative column enabled the separation and purification of these two isomers and the
compounds have been obtained in high purity. The use of reversed-phase high-performance liquid chromatography has afforded
complete analytical control of the syntheses of saturated nitrogendonor macrocyclic complexes of ruthenium, enabling identification
of the cis and trans isomers of the complex [Ru(cyclam)Cl 2]Cl. 相似文献
12.
- and -2-Methylamino and 2-benzylamino-3-hydroxymethylbicyclo [2.2.1]heptanes and the corresponding bicycio [2.2.1] heptenes ( - , - ) were synthesized from β-amino acid esters containing the norbornane or norbornene skeleton ( - ). The aminoalcohols were converted to 5,8- methano -3,1-benzoxazines by reaction with formaldehyde. As established by 1H and 13C NMR spectroscopy, the predominant conformation is ( ) for the , and ( ) for the derivatives. 相似文献
13.
BECKMANN or SCHMIDT rearrangement of ethyl trans-4-oxo-1-phenyl-2-tetralincarboxylate ( 2 ) affords ethyl trans-2,3,4,5-tetrahydro-2-oxo-5-phenyl-1 H-benzo [b] azepine-4-carboxylate ( 4 ). Mild treatment of trans-2,3,4,5-tetrahydro-1-methyl-2-oxo-5-phenyl-1 H-benzo-[b] azepine-4-carboxylic acid ( 7 ) with thionyl chloride and pyridine in dimethylformamide and subsequent reaction with an amine yields the corresponding benzazepine-4-carboxamide. If he it is applied during the preparation of the acid chloride, rearrangement occurs yielding cis and trans derivatives of hydrocarbostyril. 2,3,4,5-Tetrahydro-1,4-methano-1-methyl-5-phenyl-1 H-benzo-[b] azepinium chloride ( 25 ) reacts with primary or secondary amines to cis-tetrahydroquinoline derivatives. When heated above its melting point, trans-4,5-dihydro-2-methylamino-5-phenyl-3 H-benzo-[b] azepine-4-carboxylic acid ( 29 ) rearranges with elimination of water to a mixture of cis-and trans-2,3,3a,4-tetrahydro-1-methyl-2-oxo-4-phenyl-1 H-pyrrolo [2,3-b] quinoline ( 32 and 31 ). The reduction of 31 was investigated. The mechanisms of the rearrangements are discussed. 相似文献
14.
The C=N double bond of certain cis‐ or trans‐cycloalkane and diexo‐ or diendo‐norbornane‐condensed pyridazinones was reduced with NaBH 3CN. The cis‐ or trans nature of the starting cycloalkane derivatives was always retained in the saturated products, with a high degree of diastereoselectivity: the hydrogen on the new stereocenter and the annelational hydrogen next to the carbonyl always exhibited the same steric orientation. The stereostructures were determined by means of nmr measurements and confirmed by molecular modelling. 相似文献
15.
The reactions of 3-amino-1-phenyl-and 3-amino-1-(thien-2-yl)-4,4,4-trifluorobut-2-en-1-ones with 1,2-diaminopropane under
kinetically controlled conditions afford mixtures of cis and trans isomers of 2-aroylmethyl-4-methyl-2-trifluoromethylimidazolidines. Analogous reactions with 1,2-diamino-3,3,3-trifluoropropane
yield cis-2-aroylmethyl-2,4-bis(trifluoro-methyl)imidazolidines.
Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2135–2139, November, 1999. 相似文献
16.
The preparation of the diastereoisomers of 1-amino-2-bromocyclopropanecarboxylic acid is described using the methyl (1 RS, 5 SR)-2-oxo-3-oxabicyclo[3.1.0]hexane-1-carboxylate 5 as starting material. The key step is the oxidation of 9 with subsequent radical introduction of bromine according to the Barton procedure. The 2-bromo-cyclopropanecarboxylates cis- 11 and trans- 11 were obtained as diastereoisomer mixture in a ratio of 3:1. They were converted into cis- and trans-esters 12 and the acids 13 . 相似文献
17.
The reaction of [TcNCl 2(PPh 3) 2] with 2,2′:6′,2″-terpyridine produced cis-[TcNCl 2(terpy)] selectively. The resulting complexes were characterized by 1H NMR and IR spectroscopy. The geometries of the cis and trans isomers were estimated by theoretical calculations following a density functional method. The cis isomer is likely more stable than the trans one with respect to the trans influence of the nitrido ligand. Furthermore, the behavior of nitridotechnetium complexes in polar solvents was compared
to Os-analogues. 相似文献
18.
(1 R,1′ R,2 S,4 R)-1,7,7-Trimethylspiro[bicyclo[2.2.1]heptane-2,2′-[1,3]dithiolane] 1′-oxide, (1 R,2 S,3′ R,4 R)-1,7,7-trimethylspiro[bicyclo[2.2.1]heptane-2,2′-[1,3]dithiolane] 1′,1′,3′-trioxide, and (1 R,4 R)-1,7,7-trimethylspiro[bicyclo[2.2.1]heptane-2,2′-[1,3]dithiolane] 1′,1′,3′,3′-tetraoxide were synthesized by oxidation of
camphor ethylene dithioacetal with m-chloroperoxybenzoic acid at different substrate-tooxidant ratios. The structure of the products was proved by IR and NMR
spectroscopy and X-ray analysis. 相似文献
19.
Potassium methyl pyrrole-2-carboxylate and styrene oxide are shown to yield trans-1-styrylpyrrole-2-carboxylic acid (dry conditions) and 1-(2-hydroxy-2-phenylethyl)pyrrole-2-carboxylic acid (moist conditions). The hydroxy acid yields 1H-3-phenyl-3,4-dihydropyrrolo[2.1- c]-[1.4]oxazin-1-one, on treatment with polyphosphoric acid. Vinyl acids were also obtained from the potassium pyrrole ester and ethylene oxide, propylene oxide, and cis- and trans-stilbene oxide; the latter two compounds yielded stereospecific products. A pyrrolo[2.1- c]-[1.4]benzoxazinone was obtained from cyclohexene oxide. The photo chemical isomerization of the trans-1-styryl acid and the attempted conversion into lactones is described. 相似文献
20.
The pure cis- and trans-isomers of ethyl N-(2-pyridinyl)aminomethylenecyanoacetates were obtained and their structure and their interconvertibility is diseussed. 4 H-Pyrido[1,2- a]pyrimidin-4-one-3-carboxylic acids were synthesized by treatment of both cis- and trans-isomers with hydrochloric acid. 相似文献
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