共查询到20条相似文献,搜索用时 950 毫秒
1.
Kenichi Takeuchi Tadakazu Miyazaki Itsuko Kitagawa Kunio Okamoto 《Tetrahedron letters》1985,26(5):661-664
The reaction of 1-adamantyl triflate () with carbon monoxide and adamantane catalyzed by triflic acid affords 3-hydroxy-4-homoadamantyl 1-adamantanecarboxylate () as a major product, which is easily converted to 3,4-homoadamantanediol () — a promising starting material for 3,4-bifunctional homoadamantane derivatives. 相似文献
2.
Masahiro Hirama David S. Garvey Linda D.-L. Lu Satoru Masamune 《Tetrahedron letters》1979,20(41):3937-3940
The -vinyloxyborane (), prepared from S-phenyl propanethioate, 9-BBN triflate, and diisopropylethylamine, reacts stereoselectively with aldehydes to provide -β-hydroxy-α-methylcarboxylic acid thiol esters. This reaction has been applied to a synthesis of Prelog-Djerassi lactonic acid (). 相似文献
3.
4.
Tatsuhiko Kanmera Sannamu Lee Haruhiko Aoyagi Nobuo Izumiya 《Tetrahedron letters》1979,20(46):4483-4486
A series of cyclo (Δaminoacyl-L-Ala) () (Δ=α,β-dehydro) were prepared from cyclo(Gly-L-Ala) and corresponding aldehyde, and hydrogenated with Pd black in MeOH. Chiral inductions producing cyclo (L-aminoacyl-L-Ala) () from were 96–99% in the case of L-Aba (2-aminobutanoic acid), L-Val, L-Leu, and L-App (2-amino-5-phenylpentanoic acid) as an L-aminoacyl moiety in . Pure L-Leu, L-Aba, and L-App were synthesized in preparative scale from corresponding through asymmetric hydrogenation and acid-hydrolysis. 相似文献
5.
The vinyloxyborane(5), prepared from (+)--phenyl-3()-butanethioate, 9-BBN triflate and diisopropylethylamine, reacted with -(3-benzyloxypropylidene)benzylamine to give the β-benzylamino thiol ester(6) in a moderate yield, which was efficiently converted to the optically pure thienamycin intermediate(10). 相似文献
6.
A new backbone rearrangement is observed in A/B methyl lithocholate derivatives. It is initiated from the C-3 carbon either by dehalogenation of the chloroesters by AgSbFg6 or by the action of the triflic anhydride on the si1y1ated ether . This rearrangement leads to methyl diacholenate and new lactones in D-homoandrostane series and . The differences of behaviour between A/B and A/B series and the mechanism of rearrangements are discussed. 相似文献
7.
Fumio Sanda Tsuyoshi Shinjo Wonmun Choi Takeshi Endo 《Macromolecular rapid communications》2001,22(5):363-366
This article deals with the cationic and anionic depolymerization of polydithiocarbonate, which was synthesized by cationic polymerization of 5‐phenoxymethyl‐1,3‐oxathiolane‐2‐thione ( 1 ) using methyl triflate as the initiator. The cationic depolymerization of the obtained polymer was carried out in the presence of 5–20 mol‐% of methyl triflate or triflic acid catalyst in chlorobenzene at 60 °C for 96 h to afford 4‐phenoxymethyl‐1,3‐dithiolan‐2‐one ( 2 ) in 35–83% yield. The anionic depolymerization of the polymer was carried out in the presence of 5 mol‐% of triethylamine or potassium tert‐butoxide at 20 °C for 24 h to afford 2 in 85–100% yield. 相似文献
8.
The thiogibberellin analogs and were synthesized via sulfhysdrolysis of the carboxylic acid anhydrides and and transformed photochemically to the corresponding 7→15α-thiololactones and . 相似文献
9.
K.J.L. Paciorek D.H. Harris M.E. Smythe J.H. Nakahara R.H. Kratzer 《Journal of fluorine chemistry》1985,28(4):387-398
1,3-Bis(phenylchlorophospha)-5-perfluoroalkyl-2,4,6- triazine and the corresponding perfluoroalkylether analogue were synthesized by interaction of equimolar amounts of the respective amidines and imido-diphenyl-diphosphinic acid pentachloride. With additional quantities of amidine, 1,3-bis(phenylperfluoro--octanoylamidinophospha)-5-perfluoro- -heptyl-2,4,6-triazine was obtained. The replacement of the chloro- by azido-groups in 1,3-bis(phenylchlorophospha)-5- perfluoro--heptyl-2,4,6-triazine proceeded readily. The mass spectral breakdown patterns of the chloro- and the amidino- substituted compounds were directly comparable to those of the bis(diphenylphospha)-s-triazines. 相似文献
10.
The β (1 → 3) -linked disaccharide was synthesized from -galactose and a -galactosamine unit with a watersoluble amide spacer. This represents the hapten of T-antigen and, when coupled to a protein, is suitable for use as an artificial antigen. Other O-β--galactosylated derivatives of galactosamine were synthesized. 相似文献
11.
Marjorie F. Dubreuil Nadia G. Farcy Eric J. Goethals 《Macromolecular rapid communications》1999,20(7):383-386
Esters of trifluoromethane sulfonic acid have been synthesized by reaction of different alcohols with triflic anhydride and used in situ as initiators for the polymerization of tetrahydrofuran. Kinetic studies of the polymerization showed that allyl triflate has the highest reactivity and that an increase of the alkyl chain length of the initiator leads to a significant decrease of the initiation rate. “Non-linear” triflate ester such as isobutyl triflate leads to incomplete initiation. It was impossible to synthesize quantitatively the triflate from tert-butyl alcohol due to spontaneous elimination leading to isobutylene. 相似文献
12.
(1,5)-(-)-Karahana ether (8,8-dimethyl-2-methylene-6-oxabi-cyclo[ 3.2.1]octane) and (1,5)-(-)-karahana lactone (8,8-dimethyl-2-methylene-6-oxabicyclo [3.2.1]octan-7-one) were synthesized from ()-3-hydroxy-2,2-dimethylcyclo-hexanone. The natural karahana lactone was shown to be almost racemic (. 1.3 % e.e.). 相似文献
13.
(?)-Terrecyclic acid A () was synthesized from (+)-fenchone (). The absolute configuration of terrecyclic acid A and quadrone was established. 相似文献
14.
For the first time a perfluoroalkanesulfonylallene, the 1-phenyl-3-(trifluoromethanesulfonyl)-propadiene () was synthesized. is reacts already at room temperature with cyclopentadiene to form the adduct . 相似文献
15.
Natural warburganal (1b) and 4α-methoxycarbonyl congener (1a) were efficiently synthesized from 1-ãbietic acid () by selective and oxidative 相似文献
16.
N-t-Butyldimethylsilylpyridinium triflate reacted with Grignard reagents at 4-position with almost complete regioselectivity (99%) to afford the corresponding 1,4-dihydropyridine derivatives (), which are easily oxidized by oxygen to give 4-substituted pyridines (: 58 – 70%). 相似文献
17.
《Tetrahedron》1987,43(4):701-709
The carbonylation of the l-adamantyl cation with carbon monoxide in carbon tetrachloride at atmospheric pressure in the presence of trifluo-romethanesulfonic acid (triflic acid) and adamantane affords 3-hydroxy-4-homoadamantyl l-adamantanecarboxylate (2) in 70% yield under appropriate conditions. Among various l-adamantyl cation precursors tested, l-adamantyl trifluoromethanesulfonate (triflate) and methanesulfonate (mesylate) have given the best, comparable results. As to the acid catalyst, fluorosulfonic acid is less effective than triflic acid, and 100% sulfuric acid and methanesulfonic acid are completely ineffective to produce 2. It is recommended to use five mol each of triflic acid and adamantane per mol of l-adamantyl mesylate or triflate. This reaction proceeds via the addition of the l-adamantanecarbonyl cation to l-adamantanecarbaldehyde, a transient intermediate, followed by the Wagner-Meerwein rearrangement. The hydroxy ester 2 is easily converted into 3,4-homoadamantanediol which is a promising starting material for 3,4-bifunctional homoadamantane derivatives. 相似文献
18.
3-Methylisoguanosine () has been synthesized from 5-(cyanomethylamino)-1(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)imidazole-4-carboxamide () through the carbonitrile (). 相似文献
19.
Yoshimitsu Nagao Kaoru Seno Kohji Kawabata Tadayo Miyasaka Sachiko Takao Eiichi Fujita 《Tetrahedron letters》1980,21(9):841-844
3-Acylthiazolidine-2-thiones () were easily prepared and they were treated with several amines in dichloromethane to give amides in very high yields within a short time. Aminoalcohols and aminophenols were selectively converted into acylaminoalcohols and acylaminophenols, respectively, by this reaction. One can monitor the reaction by disappearance of the yellow color of the starting material . Some amide alkaloids (–) have effectively been synthesized. 相似文献
20.
Kenji Mori 《Tetrahedron letters》1984,25(35):3875-3878
The enantiomers of the olive fly pheromone (1 and 4) were synthesized from ()-malic acid in amounts sufficient for the biological test. 相似文献