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1.
C. G. Overberger T. Nishiyama 《Journal of polymer science. Part A, Polymer chemistry》1981,19(2):311-330
(+) (S)- and (?) (R)-trans-1,2-cyclopropanedicarboxylic acids (C3A), (+) (S)- and (?) (R)-trans-1,2-diaminocyclopropanes (C3B), (+) (S)- and (?) (R)-trans-2-phenylcyclopropylamines (øC3B), (+) (S)- and (?) (R)-trans-1,2-bis(methylamino)-cyclopropanes (C3MB), and (+) (S)- and (?) (R)-trans-(2-phenylcyclopropyl)-methylamines (øC3MB) were prepared. 相似文献
2.
The 6 R configuration of (+)-cis-γ-irone [(+)- 4 ] was established by chemical correlation with (—)-camphor. (+)-cis-γ-irone [(+)- 4 ] was converted into (+)-cis-α-irone [(+)- 1 ], (?)-trans-α-irone [(minus;;)- 2 ], and (+)-β-irone [(+)- 3 ], which therefore also have the 6 R configuration. The 2 S configurations of (+)-cis-α-irone [(+)- 1 ] and (+)-trans-α-irone [(+)- 2 ] were determined by comparison of their circular dichroism with that of R-α-ionone [(+)- 5 ]. The 2 S configuration of (+)-cis-γ-irone [(+)- 4 ] was established by chemical correlation with (+)-cis-α-irone [(+)- 1 ]. 相似文献
3.
(+)-cis-Achillene ( 10 ) and (?)-trans-achillenol (7), two monoterpenes recently isolated [1] from the essential oil of Achilleafilipendulina, were synthesized, together with their stereoisomers (?)-(9) and (+)-(8), starting from (S)-(+)-2,6-trans-dimethylocta-1,3, 7-triene ( 1 ). The isomeric ß-hymen thereties ((?)- 3 and (+)-4), often quoted [2] [3] [4] but never isolated, were obtained as intermediates. The mode of synthesis chosen establishesis (R)-chirality for naturally occurring (?)-trans-achillenol (7) and (+)-cis-achillene ( 10 ) as well as for the purely synthetic 4, 7-diene derivatives described in this paper. 相似文献
4.
《合成通讯》2013,43(22):3413-3417
ABSTRACT Conditions for efficient resolution of (±)-1-(9-anthryl)ethylamine ((±)-1) by fractional crystallization of its salts with (S)-(+)-mandelic acid (2) are reported. When crystallization was performed by fast addition of chloroform solution of an equivalent of (±)-1 to the hot chloroform solution of (+)-2, crystals of mandelate of (+)-1-(9-anthryl)ethylamine ((R,S)-3) are collected in 56% yield. (R)-(+)-1 (98.6% e.e.) is isolated by extraction from bicarbonate solution of mandelate salt. Ulterior collection of four crops afforded (R,S)-3 with 71.5% cumulative yield and >98% e.e. of (+)-1 in a any single crop. With only 0.5 equivalents of (+)-2 crystallization afforded (R,S)-3 in 47.4% yield and (+)-1 with 98.1% e.e. 相似文献
5.
Günther Ohloff Eberhard Otto Valentin Rautenstrauch Günther Snatzke 《Helvetica chimica acta》1973,56(6):1874-1882
The absolute configuration of (+)-α-ionone 3 (R), the absolute configurations at C(6) of (+)-cis-α-irone 5 (6S) and (?)-trans-α-irone 6 (6R), and the absolute configurations of (+)-cis-abscisic acid 10 (S) and (+)-trans-abscisic acid 11 (S) are deduced from the CD.-spectra. 相似文献
6.
Acids, such as p-toluenesulfonic acid, mediate the direct formation of optically active (?)-Δ6,1-3,4-trans-tetrahydrocannabinol from (+)-cis-or (+)-trans-p-menthadiene-(2,8)-ol-(1) and olivetol. 相似文献
7.
Sixteen compounds, (+)-ushinsunine-β-N-oxide ( 1 ), cleistopholine ( 2 ), liriodenine ( 3 ), (-)-anonaine ( 4 ), (+)-nornuciferine ( 5 ), (+)-N-acetylnornuciferine ( 6 ), (-)-ushinsunine ( 7 ), (-)-norushinsunine ( 8 ), (-)-asimilobine ( 9 ), (+)-reticuline ( 10 ), N-trans-feruloyltyramine ( 11 ), β-sitosterol (12) and stigmasterol ( 13 ), lyscamine ( 14 ), (-)-anaxagoreine ( 15 ) and trans-cinnamic acid ( 16 ) were isolated from the methanolic extract of the Cananga odorata. Among them, 1 is a new stereoisomer of ushinsunine-β-N-oxide. The structures of these compounds were established by means of spectral experiments. 相似文献
8.
The absolute configurations of acetylated bretonin A (= (+}-( R )-1-[(acetoxy)methyl]-2-{[(4E,6E,8E)-dodeca-4,6,8-trienyl]oxy}ethyl 4-acetoxybenzoate; (?)- 1b ) and isobretonin A (= (+)-(S)-3-{[(4E,6E,8E)-do-deca-4,6,8-trienyl]oxy}-2-hydroxypropyl 4-hydroxybenzoate; (+)-2), previously isolated from an undetermined sponge of the North Brittany sea, were established by comparison with synthetic (+)- lb and (+)- 2 , obtained from the condensation of commerical (?)-(R)-2,2-dimethyl-1,3-dioxolan-4-yl p-toluenesuifonate ((?)-(R)- 15 ) with a mixture of (4E,6E,8E)- ( 14e ) and (4E,6Z,8E)-dodeca-4,6,8-trien-1-ol ( 14z ). This also allowed confirming the structure and configuration of bretonin B (= (S)-2-{[(4E,6Z,8E)-dodeca-4,6,8-trienyl]oxy}-1-(hydroxy-methyl)ethyl 4-hydroxybenzoate; 3 ) which was also isolated from the same sponge, albeit in a too small amount for a complete study. As concerns the glyceryl ethers precursors of the bretonins, co-occurrence of the usual (S)-con-figuration (from 1a ) with the unusual (R)-configuration (from (+)- 2 )) poses intriguing biogenetic problems. 相似文献
9.
Apart from the well-known constituents (+)-β-selinene ( 2 ), (?)-β-elemene ( 4 ), (+)-β-costol ( 7 ), (?)-caryophyllene ( 17 ), and (?)-elemol ( 19 ) the following sesquiterpenoids have been isolated for the first time from costus root oil (Saussurea lappa CLARKE ): (?)-α-selinene ( 1 ), (+)-selina-4, 11-diene ( 3 ), (?)-α-trans-bergamotene ( 5 ), (?)-α-costol ( 6 ), (+)-γ-costol ( 8 ), (?)-elema-1,3,11 (13)-trien-12-ol ( 9 ), (?)-α-costal ( 11 ), (+)-γ-costal ( 12 ), (+)-γ-costal ( 13 ), (?)-elema-1,3,11 (13)-trien-12-al (elemenal, 14 ), (?)-(E)-trans-bergamota-2, 12-dien-14-al ( 15 ), (?)-ar-curcumene ( 16 ), and (?)-caryophyllene oxide ( 18 ). Compounds 6 , 8 , 9 , and 13 are new sesquiterpenoids. IR. and NMR. spectra of 12 sesquiterpenoids are reproduced. 相似文献
10.
Summary Direct resolution of four stereoisomers of the related compound of diltiazem hydrochloride, namely desacetyl diltiazem hydrochloride, was studied by both normal and reversed-phase chiral HPLC. The four stereoisomers were completely resolved on a Chiralcel OF column. The technique developed was applied to a chiral inversion study of desacetyl diltiazem hydrochloride. This inversion was observed neither in the solid state, in aqueous solution at 100°C for 3 h nor under visible light for 10h, but was observed in aqueous solution under UV irradiation.The (+)-(2S, 3S)-cis-desacetyl diltiazem hydrochloride degraded with a half-life of 1.9 h in aqueous solution under UV and epimerized to (+)-(2R, 3S)-trans-desacetyl diltiazem hydrochloride. Similarly, (+)-(2S, 3S)-cis-desacetyl diltiazem hydrochloride degraded about three times faster than diltiazem hydrochloride. Reverse epimerization of (+)-(2R, 3S)-trans-desacetyl diltiazem hydrochloride to (+)-(2S, 3S)-cis-desacetyl diltiazem hydrochloride was not observed.The overall degradation was the result of two competitive processes, the epimerization and the decomposition of the benzothiazepin ring. The degradation and epimerization rate of (+)-(2S, 3S)-cis-desacetyl diltiazem hydrochloride in solution under UV depended upon the solvent, the aqueous pH, and concentration. 相似文献
11.
D. F. Alimova Z. A. Kuliev S. Z. Nishanbaev A. D. Vdovin N. D. Abdullaev S. F. Aripova 《Chemistry of Natural Compounds》2010,46(3):352-356
Two new oligomeric proanthocyanidin glucosides were isolated from the aerial part and roots of Alhagi pseudalhagi. Their structures and relative configurations were elucidated as 7-O-β-D-Glc
\textp\xrightarrow6 {\text{p}}\xrightarrow{6} galloyl-(+)catechin-(4α-8)-(+)-catechin-(4α-8)-(–)-epigallocatechin and 7-O-β-D-Glc
\textp\xrightarrow6 {\text{p}}\xrightarrow{6} galloyl-(+)-catechin-[(4α-8)-(+)-catechin]3-(4α-8)-(–)-epigallocatechin-3-O-gallate. 相似文献
12.
(+)-cis-Khellactone methyl ether ( 4 ) and (?)-trans-khellactone methyl ether ( 6 ) had earlier been assigned the absolute configurations 3′-S; 4′-S and 3′-S; 4′-R, respectively, on the basis of the FREUDENBERG , rule. Both compounds together with their defunctionalised derivatives (?)- 7 and (+)- 8 (=(+)-lomatin), obtained from a mixture of (+)-visnadin ( 1 ) and (+)-samidin ( 2 ), were investigated by the HOREAU method. A conformational analytical study showed that the optical yield should rise in the order 4 < 6 < 7 , 8. This order was found and the α-phenylbutyric acid liberated was always dextrorotatory. The centre 3′ of the khellactones and their derivatives must be R-chiral and not S. Treatment of (?)- 6 with pyridinium perbromide gave (?)-trans-3-bromokhellactone methyl ether ( 11 ) as orthorhombic crystals. The X-ray crystal structure determination was made using the anomalous scattering of the Mo-K α radiation by Br. The result, — centre 3′ R-chiral (fig. g) — showed that the HOREAU method was correct. 相似文献
13.
A. A. Simenel Yu. V. Kuzmenko M. M. Ilyin V. V. Gumenyuk L. V. Snegur Yu. S. Nekrasov 《Russian Chemical Bulletin》2004,53(4):939-941
The stereochemistry of two processes, viz., -ferrocenylalkylation of indazole with optically active S-(+)-1-ferrocenylethanol and the thermal rearrangement of S-(+)-2-N-(ferrocenylethyl)indazole into S-(+)-1-N-(ferrocenylethyl)indazole, was studied. Both reactions proceed stereoselectively. 相似文献
14.
Graizano Guella Marino Cavazza Antonio Guerriero Francesco Pietra 《Helvetica chimica acta》1984,67(5):1248-1253
Authentic α-santolinenone ( = (+)-(4R)-1(7)-p-menthen-2-one; (+)- 1 ) is made available for the the first time in 30% overall yield from (+)-(4R)-p-menthene ((+)- 2 ) via the diastereoisomeric allylic alcohols (+)- 4a /(+)- 4b , which are oxidized to (+)- 1 with Ag2CO3/Celite. Yields are good, except for the last stage; indeed, only alcohol (+)- 4a , with equatorial OH-group, undergoes oxidation, and (+)- 1 is partly substracted via a hetero Diels-Alder dimerization giving a mixture of the diastereoisomeric dihydropyrans (+)- 5a /(+)- 5b . When Cr(VI) reagents ae used, (+)- 4a /(+)- 4b mainly give phellandral ( 6 ) and carvotanacetone ( 7 ), NnO2 reacts too sluggishly with (+)- 4a /(+)- 4b . A camphor pyrolyzate, previously thought to be 1 must be a different compound, probably 7 . 相似文献
15.
Enantiomerically pure methyl 5-bromo-5-deoxy-2,3-O- isopropylidene-β-D - (D - 5b ) and -β-l-ribofuranoside (l- 5b ) have been derived from (?)-(1R,2S,4R)-2-exo-cyano-7-oxabicylo[2.2.1]hept-5-en-endo,-yl (1′S)-camphanate ( 1 ) and (+)-(1S,2R,4S)-2-exo-cyano-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl(1′R)-camphanate ( 2 ), respectively, in 5 synthetic steps and 28% overall yield. Hydrolysis of D-5b and L - 5b afforded methyl 2,3-O isopropylidene-β-D -ribofuranoside (D -5a) and methyl 2,3-O-isopropylidene β-L-ribofuranoside (L-5a), respectively. The intermediate (+)-(1R,4R,5R,6R) 5-exo,6-exo-(isopropylidenedioxy)- 7 -oxabicyclo[2.2.1]heptan-2-one ((+)- 7 ) and its enantiomer(–)-7 were also obtained enantiomerically pure by resolution of (=)- 7 by the Johnson-Zeller method. In bothe approaches, the chiral auxiliaries ((–)- and (+)-camphanic acids, or (+)-(S)-N,S-dimethyl-S-phenylsulfoximide) were recovered at an early stage of the synthesis. 相似文献
16.
The Diels-Alder adduct of 2,4-dimethylfuran to 1-cyanovinyl (1′R)-camphanate ((+)-(1R,2S,4R)-2-exo-cyano-1,5-dimethyl-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl (1′R)-camphanate ((+)- 1 )) was converted into (+)-2,7-dideoxy-2,4-di-C-methyl-L -glycero- ((+)- 6 ) and -D -glycero-L -altro-heptono-1,4-lactone ((+)- 7 ), into (?)-(3R,4R,5R,6S)-3,4:5,7-bis(isopropylidenedioxy)-4,6-dimethylheptan-2-one ((?)- 22 ), and into (+)-(2R,3R,4R,5S,6S)-3,4:5,6-bis(isopropylidenedioxy)-2,4-dimethylheptanal ((+)- 34 ). Condensation of ((+)- 34 with the lithium enolate of (?)-(1R,4R,5S,6R)-6-exo-[(tert-butyl)dimethylsilyloxy]-1,5-endo-dimethyl-7-oxabicyclo[2.2.1] heptan-2-one ((?)- 38 ; derived from (+)- 1 ) gave a 3:2 mixture of aldols (+)- 39 and (+)- 40 (mismatched pairs of a α-methyl-substituted aldehyde and (E)-enolate) whereas the reaction of (±)- 34 with (±)- 38 gave a 10:1 mixture of aldols (±)- 41 and (±)- 39 . A single aldol, (?)- 44 , was obtained to condensing (+)- 34 with the lithium enolate of (+)-(1S,4S,5S,6S)-5-exo-(benzyloxy)-1,5-endo-dimethyl-7-oxabicyclo[2.2.1]heptan-2-one ((+)- 43 ; derived from (?)-(1S,2R,4S)-2-exo-cyano-1,5-dimethyl-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl (1′S)-camphanate ((?)- 3 )). All these cross-aldolisations are highly exo-face selective for the bicyclic ketones. The best stereochemical matching is obtained when the lithium enolates and α-methyl-substituted aldehydes can realize a ‘chelated transition state’ that obeys the Cram and Felkin-Anh models (steric effects). Polypropionate fragments containing eleven contiguous stereogenic centres and tertiary-alcohol moieties are thus prepared with high stereoselectivity in a convergent fashion. The chiral auxiliaries ((1R)- and (1S)-camphanic acid) are recovered at the beginning of the syntheses. 相似文献
17.
The synthesis of (S)-(+)-tylophorine and its seco analogues has been accomplished by using free radical reaction. (−)-N-(2,3,6,7-Tetramethoxyphenanthren-9-ylmethyl)-2-bromomethylpyrrolidine (7) and (−)-N-(2,3,6,7-tetramethoxyphenanthren-9-ylcarbonyl)-2-bromomethylpyrrolidine (9) have been obtained for the first time in three
and two linear steps from 2,3,6,7-tetramethoxyphenanthrene-9-carboxylic acid (4), respectively. When bromide 7 was subjected
to the action of tri-n-butyltin hydride and catalytic amount of azobisisobutyronitrile in acetonitrile at reflux, only a new structural N-((2,3,6,7-tetrame-thoxyphenanthren-9-yl)methyl)piperidine (2) was obtained in excellent yield, without expected (+)- tylophorine.
As an alternative route, when bromide 9 was treated with azobisisobutyronitrile and tri-n-butyltin hydride in toluene at reflux, tylophorin-9-one (10) was provided in 33.6% yield. At the same time, a new structural
(+)-N-((2,3,6,7-tetramethoxyphenanthren-9-yl)carbonyl)-2-methylpyrrolidine (11) was afforded as the main product in 65% yield.
Notably, azobisisobutyronitrile plays dual roles in this reaction, and the possible mechanism has been described. Compounds
10 and 11 were reduced by lithium aluminum hydride to give (+)-tylophorine and (+)-N-((2,3,6,7-tetramethoxyphenanthren-9-yl) methyl)-2-methylpyrrolidine (3), respectively. 相似文献
18.
Raphy Gabioud Pierre Vogel Alan A. Pinkerton Dieter Schwarzenbach 《Helvetica chimica acta》1986,69(2):271-282
The preparation and the CD spectra of optically pure (+)-trans-μ-[(1R,4S,5S,6R,7R,8S)-C,5,6,C -η : C,7,8,C-η-(5,6,7,8-tetramethylidene-2-bicyclo [2.2.2]octanone)]bis(tricarbonyliron) ((+)- 7 ) and (+)-tricarbonyl[(1S,4S,5S,6R)-C-5,6,C-η-(5,6,7,8,-tetramethylidene-2-bicyclo[2.2.2]octanone)]iron ((+)- 8 ), and of its 3-deuterated derivatives (+)-trans-μ-[(1R,3R,4S,5S,6R,7R,8S)-C,5,6,C-η : C,7,8,C-η-5,6,7,8-tetramethylidene(3-D)-2-bicyclo[2.2.2]-(octanone)]bis(tricarbonyliron) ((+)- 11 ) and (+)-tricarbonyl[(1S,3R,4S,5S,6R)-C-5,6,C- η-(5,6,7,8-tetramethylidene(3-D)-2-bicyclo[2.2.2]octanone)]iron ((+)- 12 ) are reported. The chirality in (+)- 7 and (+)- 8 is due to the Fe(CO)3 moieties uniquely. The signs of the Cotton effects observed for (+)- 7 and (+)- 8 obey the octant rule (ketone n→π*CO transition). Optically pure (?)-3R-5,6,7,8-tetramethylidene(3-D)-2-bicyclo[2.2.2]octanone ((?)- 10 ) was prepared. Its CD spectrum showed an ‘anti-octant’ behaviour for the ketone n→π*CO transition of the deuterium substituent. The CD spectra of the alcoholic derivatives (?)-trans-μ-[(1R,2R,4S, 5S,6R,7R,8S)-C,5,6,C-η : C,7,8,C- η-(5,6,7,8-tetramethylidene-2-bicyclo[2.2.2]octanol)]bis(tricarbonyliron) ((?)- 2 ) and (?)-tricarbonyl- [(1S,2R,4S,5S,6R)- C,5,6,C- η-(5,6,7,8-tetramethylidene-2-bicyclo[2.2.2]octanol)]iron ((?)- 3 ) and of the 3-denterated derivatives (?)- 5 and (?)- 6 are also reported. The CD spectra of the complexes (?)- 2 , (?)- 3 , (+)- 7 , and (+)- 8 were solvent and temperature dependent. The ‘endo’-configuration of the Fe(CO)3 moiety in (±)- 8 was established by single-crystal X-ray diffraction. 相似文献
19.
Racemic 2-trimethylsilyl- and 2-trimethylstannyl-1-(3-phenyl-2-propynyl)ferrocene (rac-1a,b) as well as the dextrorotatory specimen of the latter, (+)-1b, were synthesized in two steps from racemic 1-formyl-2-trimethylsilyl- and 1-formyl-2-trimethylstannylferrocenes (2a,b) or from the levorotatory specimen of the latter, (–)-2b, respectively. On the contact with strongly alkaline alumina compounds1a,b and (+)-1b undergo diastereoselective prototropic acetylene-allene rearrangement to give predominantly one of the two possible stereoisomers of 2-trimethylsilyl- or 2-trimethylstannyl-1-(3-phenyl-1,2-propadienyl)ferrocenes,rac-4a,b or (+)-4b, depending on the starting material (d. e. 30–40 %). The extent of intramolecular asymmetric induction in the formation of the axially chiral fragment during the transformation of (+)-1b to (+)-4b is estimated at 38 %.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1111– 1115, June, 1994.The work was carried out with financial support from the Russian Fundamental for Basic Research (Project No.93-03-5827). 相似文献
20.
Epoxidation of (?)-(1R,2R,4R)-2-endo-cyano-7-oxabicyclo[2.2.1]hept-5-en-2-exo-yl acetate ((?)-5) followed by saponification afforded (+)-(1R,4R,5R,6R)-5,6-exo-epoxy-7-oxabicyclo[2.2.1]heptan-2-one ((+)-7). Reduction of (+)-7 with diisobutylaluminium hydride (DIBAH) gave (+)-1,3:2,5-dianhydroviburnitol ( = (+)-(1R,2R,3S,4R,6S)-4,7-dioxatricyclo[3.2.1.03,6]octan-2-ol; (+)-3). Hydride reductions of (±)-7 were less exo-face selective than reductions of bicyclo[2.2.1]heptan-2-one and its derivatives with NaBH4, AlH3, and LiAlH4 probably because of smaller steric hindrance to endo-face hydride attack when C(5) and C(6) of the bicyclo-[2.2.1]heptan-2-one are part of an exo oxirane ring. 相似文献