- Oxysterols: 27-hydroxycholesterol and its radiolabeled analog
-
We describe a convenient and stereoselective route to the synthesis of 27-hydroxycholesterol. Also its radiolabeled analog, 22, 23 di [3H]-27-hydroxycholesterol with high specific radioactivity (55 Ci/mmol) was synthesized by this method. Julia
- D'Ambra, Thomas E.,Javitt, Norman B.,Lacy, James,Srinivasan, Puliyur,Warchol, Tadeusz
-
-
Read Online
- Total synthesis of four stereoisomers of methyl 4,8,12-trimethylpentadecanoate, a major component of the sex pheromone of the stink bug: Edessa meditabunda
-
The male-produced sex pheromone of the stink bug Edessa meditabunda was previously identified as a mixture of the esters methyl 4,8,12-trimethylpentadecanoate (1) and methyl 4,8,12-trimethyltetradecanoate (2), produced in a ratio of 92 : 8, respectively.
- Schulz, Stefan,Szczerbowski, Daiane,Zarbin, Paulo Henrique Gorgatti
-
p. 5034 - 5044
(2020/07/30)
-
- Enantioselective Synthesis and Activity of All Diastereoisomers of (E)-Phytal, a Pheromone Component of the Moroccan Locust, Dociostaurus maroccanus
-
The Moroccan locust, Dociostaurus maroccanus (Thunberg, 1815) (Orthoptera: Acrididae), is a polyphagous pest capable of inflicting large losses in agriculture under favorable environmental and climatic conditions. Currently, control of the pest relies solely on the application of conventional insecticides that have negative effects on the environment and human safety. In the search for a more rational, environmentally acceptable approach for locust control, we have previously reported that (Z/E)-phytal (1) is a male-produced candidate sex pheromone of this acridid. This molecule, with two stereogenic centers at C-7 and C-11, has four different diastereomers along with the Z/E stereochemistry of the double bond at C-2. In this paper, we present for the first time the enantioselective synthesis of the four diastereomers of (E)-phytal and their electrophysiological and behavioral activity on males and females. Our results demonstrate that the (R,R)-phytal is the most active diastereomer in both assays, significantly attracting females in a double-choice Y olfactometer, and confirming the previous chromatographic assignment as component of the sex pheromone of the Moroccan locust.
- Guerrero, Angel,Ramos, Victoria Elena,López, Sergio,Alvarez, José María,Domínguez, Aroa,Coca-Abia, María Milagro,Bosch, María Pilar,Quero, Carmen
-
-
- SUBSTITUTED PYRAZOLOAZEPIN-4-ONES AND THEIR USE AS PHOSPHODIESTERASE INHIBITORS
-
The present invention relates to novel substituted pyrazoloazepin-4-ones with phosphodiesterase inhibitory activity, as well as to their use as therapeutic agents the treatment of inflammatory diseases and conditions.
- -
-
Page/Page column 42
(2018/07/05)
-
- SUBSTITUTED PYRAZOLOAZEPIN-4-ONES AND THEIR USE AS PHOSPHODIESTERASE INHIBITORS
-
The present invention relates to novel substituted pyrazoloazepin-4-ones with phosphodiesterase inhibitory activity, as well as to their use as therapeutic agents in the treatment of inflammatory diseases and conditions.
- -
-
Page/Page column 38
(2018/07/05)
-
- Strictly Alternating Sequences When Copolymerizing Racemic and Chiral Acetylene Monomers with an Organo-Rhodium Catalyst
-
A racemic mixture and two chiral monomers of 2-methyl-1-butyl propiolate, i.e., rac1, R1, and S1, were stereoregularly polymerized with a catalyst, [Rh(norbornadiene)Cl]2, in methanol at 40 °C to obtain the corresponding helical racemic and two chiral polymers, Prac1, PR1, and PS1, and a copolymer, Pco. The 1H and 13C NMR spectra of the racemic and chiral polymers differed, although the NMR spectra of their monomers were the same. The structures of the Pco copolymers with different chiral monomer ratios were analyzed using 1D and 2D NMR, optical rotation, circular dichroism (CD), UV-vis, and computational methods to elucidate the stereochemical effect of the chiral monomers together with the polymerization mechanism. The temperature dependence of 1H and 13C NMR spectra in line shape and intensity indicated that the helical main chain undergoes restricted rotation around the ester methylene bonds ?O-CH2- through a three-site jump exchange called an accordion-like helix oscillation (HELIOS). The energetically preferred structures of the helical-sense polymers PR1 or PS1 were simulated using the MMFF94 program. The dependence of the NMR spectral line shapes, optical rotations, and calculated structures on the monomer feed clearly indicated that the copolymers alternatively incorporate R1 and S1 to generate one-handed helical-sense chains. Based on these results, a polymerization mechanism is proposed, explaining a strictly alternating copolymerization that yields helical chains.
- Yoshida, Yoshiaki,Mawatari, Yasuteru,Sasaki, Takahiro,Hiraoki, Toshifumi,Wagner, Manfred,Müllen, Klaus,Tabata, Masayoshi
-
p. 1291 - 1301
(2017/03/09)
-
- Toward a new palmerolide assembly strategy: Synthesis of C16-C24
-
Asymmetric synthesis of C16-C24 of palmerolide A is described, featuring convergent Negishi coupling, Singaram propargylation, and successful tactical maneuvering to address an unexpected allylic substitution reaction. Georg Thieme Verlag Stuttgart · New York.
- Lisboa, Marilda P.,Jeong-Im, Jeannie H.,Jones, David M.,Dudley, Gregory B.
-
scheme or table
p. 1493 - 1496
(2012/07/28)
-
- Isolation, structural elucidation, and biosynthesis of 15-norlankamycin derivatives produced by a type-II thioesterase disruptant of Streptomyces rochei
-
Lankamycin, a 14-membered macrolide antibiotic, contains a 3-hydroxy-2-butyl side chain at C-13. To analyze the function of lkmE, which encodes type-II thioesterase in the lankamycin cluster, we carried out a gene disruption experiment. Disruption of lkmE
- Arakawa, Kenji,Cao, Zhisheng,Suzuki, Natsumi,Kinashi, Haruyasu
-
supporting information; experimental part
p. 5199 - 5205
(2011/08/06)
-
- Hierarchical chiral expression from the nano- to mesoscale in synthetic supramolecular helical fibers of a nonamphiphilic C 3-symmetrical π-functional molecule
-
The controlled preparation of chiral structures is a contemporary challenge for supramolecular science because of the interesting properties that can arise from the resulting materials, and here we show that a synthetic nonamphiphilic C3 compound containing π-functional tetrathiafulvalene units can form this kind of object. We describe the synthesis, characterization, and self-assembly properties in solution and in the solid state of the enantiopure materials. Circular dichroism (CD) measurements show optical activity resulting from the presence of twisted stacks of preferential helicity and also reveal the critical importance of fiber nucleation in their formation. Molecular mechanics (MM) and molecular dynamics (MD) simulations combined with CD theoretical calculations demonstrate that the (S) enantiomer provides the (M) helix, which is more stable than the (P) helix for this enantiomer. This relationship is for the first time established in this family of C3 symmetric compounds. In addition, we show that introduction of the wrong enantiomer in a stack decreases the helical reversal barrier in a nonlinear manner, which very probably accounts for the absence of a majority rules effect. Mesoscopic chiral fibers, which show inverted helicity, i.e. (P) for the (S) enantiomer and (M) for the (R) one, have been obtained upon reprecipitation from dioxane and analyzed by optical and electronic microscopy. The fibers obtained with the racemic mixture present, as a remarkable feature, opposite homochiral domains within the same fiber, separated by points of helical reversal. Their formation can be explained through an oscillating crystallization mechanism. Although C3 symmetric disk-shaped molecules containing a central benzene core substituted in the 1,3,5 positions with 3,3′-diamido-2,2′-bipyridine based wedges have shown peculiar self-assembly properties for amphiphilic derivatives, the present result shows the benefits of reducing the nonfunctional part of the molecule, in our case with short chiral isopentyl chains. The research reported herein represents an important step toward the preparation of functional mesostructures with controlled helical architectures.
- Danila, Ion,Riobe, Francois,Piron, Flavia,Puigmarti-Luis, Josep,Wallis, John D.,Linares, Mathieu,Agren, Hans,Beljonne, David,Amabilino, David B.,Avarvari, Narcis
-
supporting information; experimental part
p. 8344 - 8353
(2011/07/08)
-
- Stereochemistry of enacyloxins. Part 5: Synthesis of a C9′-C15′ fragment of enacyloxins, a series of antibiotics from Frateuria sp. W-315
-
The C9′-C15′ fragment of enacyloxins, a series of antibiotics isolated from Frateuria sp. W-315, was synthesized from diethyl D-tartrate. Copyright by Walter de Gruyter Berlin Boston.
- Furukawa, Hiroyuki,Hoshikawa, Hiroaki,Igarashi, Wataru,Yaosaka, Manabu,Yamada, Teiko,Kuwahara, Shigefumi,Kiyota, Hiromasa
-
scheme or table
p. 3 - 5
(2011/10/08)
-
- Synthesis of all the stereoisomers of 6-methyl-2-octadecanone, 6,14-dimethyl-2-octadecanone, and 14-methyl-2-octadecanone, the components of the female-produced sex pheromone of a moth, Lyclene dharma dharma
-
All of the stereoisomers of the components of the female-produced sex pheromone of a moth, Lyclene dharma dharma, were synthesized. They are (R)- and (S)-6-methyl-2-octadecanone, (6R,14R)-, (6R,14S)-, (6S,14R)-, and (6S,14S)-6,14-dimethyl-2-octadecanone, and (R)- and (S)-14-methyl-2-octadecanone. Enantiomers of citronellal and methyl (S)-3-hydroxy-2-methylpropanoate were the starting materials, and olefin cross metathesis was employed as the key reaction.
- Mori, Kenji
-
scheme or table
p. 2798 - 2805
(2009/08/15)
-
- Total Synthesis of rapamycin
-
For over 30 years, rapamycin has generated a sustained and intense interest from the scientific community as a result of its exceptional pharmacological properties and challenging structural features. In addition to its well known therapeutic value as a potent immunosuppressive agent, rapamycin and its derivatives have recently gained prominence for the treatment of a wide variety of other human malignancies. Herein we disclose full details of our extensive investigation into the synthesis of rapamycin that culminated in a new and convergent preparation featuring a macro-etherification/catechol-templating strategy for construction of the macrocyclic core of this natural product.
- Ley, Steven V.,Tackett, Miles N.,Maddess, Matthew L.,Anderson, James C.,Brennan, Paul E.,Cappi, Michael W.,Heer, Jag P.,Helgen, Celine,Kori, Masakuni,Kouklovsky, Cyrille,Marsden, Stephen P.,Norman, Joanne,Osborn, David P.,Palomero, Maria A.,Pavey, John B. J.,Pinel, Catherine,Robinson, Lesley A.,Schnaubelt, Juergen,Scott, James S.,Spilling, Christopher D.,Watanabe, Hidenori,Wesson, Kieron E.,Willis, Michael C.
-
supporting information; experimental part
p. 2874 - 2914
(2009/12/25)
-
- Synthesis of brassinolide and its biosynthetic precursors using methyl 3-hydroxy-2-methylpropionate
-
Formal synthesis of plant hormones that belong to the group of 24α-methylbrassinosteroids, including brassinolide and its biosynthetic precursors with one hydroxyl group in their side chain, was performed. Stereochemistry of a methyl group at the C24 atom
- Khripach,Zhabinskii,Parkhimovich,Gulyakevich
-
experimental part
p. 240 - 249
(2010/04/26)
-
- General synthetic approach to bicyclo[9.3.0]tetradecenone: A versatile intermediate to clavulactone and clavirolides
-
An efficient and stereoselective approach to the bicyclo[9.3.0] tetradecenone core structure of clavulactone starting from readily and abundantly available 2-methyl-1,3-cyclopentandione employing microbial desymmetrization and cyanohydrin alkylation as th
- Sun, Bingfeng,Xu, Xingxiang
-
p. 8431 - 8434
(2007/10/03)
-
- Regio- and stereochemical study of sex pheromone of pine sawfly; Diprion nipponica
-
Regio- and stereoisomers of 1,2,ω-trimethyldecyl propionate (ω = 5-9) were prepared from stereochemically pure chiral building blocks as sex pheromone candidates of a pine sawfly; Diprion nipponica. Among the synthesized candidates, (1S,2R,8S)-1,2,8-trimethyldecyl propionate was found to be the sex pheromone of D. nipponica, based on compatibility of its GC-MS data with that of the extract of females, and its significantly high pheromone activity in a field bioassay. The field bioassay of the synthesized compounds also revealed that (1S,2R,SR)-1,2,8-trimethyldecyl propionate, (1S,2R,7S)-1,2,7-trimethyldecyl propionate, and (1S,2R,6S)-1,2,6-trimethyldecyl propionate could attract male sawflies to some extent as pheromone mimics.
- Tai, Akira,Syouno, Emi,Tanaka, Kazuki,Fujita, Morifumi,Sugimura, Takashi,Higashiura, Yasutomo,Kakizaki, Masashi,Hara, Hideho,Naito, Tikahiko
-
p. 111 - 121
(2007/10/03)
-
- Synthesis of (3S,7S)- and (3S,7S,15S)- stereoisomers of 3,7-dimethyl-2- heptacosanone and 3,7,15-trimethyl-2-heptacosanone, the ketones identified from the locust Schistocerca gregaria
-
The (3S,7S) and (3S,7S,15S) stereoisomers of 3,7-dimethyl-2- heptacosanone (1) and 3,7,15-trimethyl-2-heptacosanone (2), the ketones identified from the locust Schistocerca gregaria, were synthesized by employing (2R,6S)-7-acetoxy-2,6-dimethyl-1-heptanol (4) as the starting material.
- Nakamura, Yoshihide,Mori, Kenji
-
p. 1307 - 1312
(2007/10/03)
-
- Synthesis of Microcolin B, a Potent New Immunosuppressant Using an Efficient Mixed Imide Formation Reaction
-
Microcolin B, a potent new immunosuppressant isolated from blue-green alga Lyngbya majuscula off the Venezuelan coast, has been made using a methyl-directed asymmetric hydrogenation reaction with rhodium on alumina catalyst on lactone 4 for the synthesis of the key (R,R)-2,4-dimethyl-octanoic acid fragment 1. A new, direct mixed imide formation reaction was also developed for the production of the unusual prolylpyrrolen-2-one 2 portion of microcolin. The pentafluorophenyl ester of CBZ-proline 5 was reacted with the lithium imidate of lactam 6, providing the mixed imide in 80% yield. Coupling of acid 1 with the N-terminus of the tripeptide, followed by coupling with pyrrolylproline 2, gave microcolin B. The new mixed-imide forming reaction was also applied to a formal total synthesis of microcolin A. The pentafluorophenyl ester of TBS-protected cis-hydroxyproline was coupled with lactam 6, and the resultant imide was converted to the key pyrrolylproline made previously for microcolin A.
- Andrus, Merritt B.,Li, Wenke,Keyes, Robert F.
-
p. 5542 - 5549
(2007/10/03)
-
- Synthesis of (25R)-cholest-5-ene-3β,26-diol and its radiolabeled analog
-
A new, convenient and stereoselective route to the synthesis of (25R)-cholest-5-ene-3β,26-diol (1) and its radiolabeled analog 4 is described. The key step is a Julia condensation of sulfone 6 with aldehyde 12 to furnish compound 13. Further reduction of
- D'Ambra, Thomas E.,Javitt, Norman B.,Nakanishi, Koji,Warchol, Tadeusz
-
p. 3801 - 3804
(2007/10/03)
-
- Pheromone synthesis, CLXXIV: Synthesis of (5R,11S)-5,11-Dimethylheptadecane and (S)-2,5-Dimethylheptadecane, the major and the minor components of the sex pheromone of the geometrid moth, Lambdina fiscellaria lugubrosa
-
(5R,11S)-5,11-Dimethylheptadecane (1), the major component of the female-produced sex pheromone of the western hemlock looper (Lambdina fiscellaria lugubrosa), was synthesized by starting from the enantiomers of methyl 3-hydroxy-2-methylpropanoate (3). (S)-2,5-Dimethylheptadecane (2), the minor and synergistic component of the pheromone, was also synthesized by starting from (S)-citronellol (4). VCH Verlagsgesellschaft mbH, 1996.
- Mori, Kenji,Horikiri, Hiromasa
-
p. 501 - 505
(2007/10/03)
-
- An Alkylative Strategy to the C-13 to C-21 Sector of Discodermolide
-
An approach to the C-13 to C-21 sector if the immunosuppressive marine natural product discodermolide (1) is described.The C-15 to C-16 bond is formed by diastereoselective alkylation of a ketone enolate.Either diastereomer of alkylation can be obtained by selecting the appropriate counter ion.The C-16 to C-21 subunit is prepared in two steps from 11.
- Yang, Ge,Myles, David C.
-
p. 1313 - 1316
(2007/10/02)
-
- The synthesis of the C-9 to C-21 sector of discodermolide: An efficient route to the C13-14 Z-trisubstituted alkene
-
The synthesis of the C-9 to C-21 sector of the immunosuppressive marine natural product discodermolide is described. The C-9 to C-15 subunit is synthesized in five steps from aldehyde 5 using the diene aldehyde cyclocondensation reaction. Diastereoselective alkylation of the previously synthesized C-16 to C-21 subunit by a suitably functionalized C-9 to C-15 synthon (3) leads to the C-9 to C-21 sector of discodermolide.
- Yang, Ge,Myles, David C.
-
p. 2503 - 2504
(2007/10/02)
-
- Synthetic study on tautomycin. Stereocontrolled synthesis of C(1)-C(18) fragment using a strategy of selective reduction of spiroketal
-
A stereocontrolled synthesis of C(1)-C(18) fragment of tautomycin is accomplished employing asymmetric crotylboration, selective reduction of spiroketal, and addition of crotylstannane as the key steps.
- Oikawa,Oikawa,Ichihara
-
p. 4797 - 4800
(2007/10/02)
-
- The synthesis and biochemical pharmacology of enantiomerically pure methylated oxotremorine derivatives
-
Previous pharmacological studies of methylated oxotremorine derivatives bearing substituents at the 3-, 4-, and 5-positions of the pyrrolidinone ring have been conducted using racemic mixtures, and not with optically active compounds. The synthesis and radioligand binding data of optically active, methylated oxotremorine derivatives at the 3- and 4-positions are described. There are significant pharmacological differences between the 3- and 4- position derivatives. The 4-position enantiomers have weak, approximately equal affinity and antagonist-like profiles, whereas the 3-position enantiomers have significantly different affinities and partial agonist-like profiles.
- Trybulski,Zhang,Kramss,Mangano
-
p. 3533 - 3541
(2007/10/02)
-
- Pheromone Synthesis, CXXX. Synthesis of (4S,8S)- and (4S,8R)-4,8-Dimethyldecanal, the Stereoisomers of the Aggregation Pheromone of Tribolium castaneum
-
(4S,8S)- and (4S,8R)-4,8-Dimethyldecanal (1) were synthesized by starting from (R)-citronellic acid (2a), methyl (S)-3-hydroxyy-2-methylpropanoate (3a), and (S)-2-methyl-1-butanol (4a).
- Mori, Kenji,Takikawa, Hirosato
-
p. 497 - 500
(2007/10/02)
-
- New Approaches to the Synthesis of trans-Alkene Isosteres of Dipeptides
-
Two new syntheses of protected dipeptide analogues bearing a trans carbon-carbon double bond in place of the amide linkage are reported.One route is a linear synthesis employing the rearrangement of an allylic selenide to a protected allylic amine.The second route is convergent and uses the Julia olefin synthesis in a key step.The latter route is fully stereocontrolled and has been used to prepare protected trans-alkene isosteres of the dipeptides TyrAla, PhePhe, LeuPhe, and LeuLeu.
- Spaltenstein, Andreas,Carpino, Philip A.,Miyake, Fumio,Hopkins, Paul B.
-
p. 3759 - 3766
(2007/10/02)
-
- A FORMAL SYNTHESIS OF (+)MILBEMYCIN β3: A WITTIG APPROACH
-
A new route has been established to generate the C14-C15 trisubstituted double bond of milbemycin β3 by reaction of a Wittig reagent with the appropriate spiroacetal aldehyde.The product of this reaction, after conversion to the iodide and enan
- Baker, Raymond,O'Mahony, Mary J.,Swain, Christopher J.
-
p. 3059 - 3062
(2007/10/02)
-
- A STEREOCONTROLLED SYNTHESIS OF TRANS-ALKENE ISOSTERES OF DIPEPTIDES
-
A general synthetic route to trans-alkene isosteres of protected dipeptides is reported.This sequence permits the fully stereocontrolled preparation of these isosteres in optically active form and in quantities sufficient for further biological study.Prep
- Spaltenstein, Andreas,Carpino, Philip A.,Miyake, Fumio,Hopkins, Paul B.
-
p. 2095 - 2098
(2007/10/02)
-
- SYNTHESIS OF THE ENANTIOMERS OF CIS-2-METHYL-5-HEXANOLIDE, THE MAJOR COMPONENT OF THE SEX PHEROMONE OF THE CARPENTER BEE
-
(2R,5S)-2-Methyl-5-hexanolide and its antipode were synthesized in highly optically pure state (98-99percent e.e.) starting from ethyl (S)-lactate and the enantiomers of methyl β-hydroxyisobutyrate.The specific rotations of our samples were D +/- 91.0 -93.5 deg (CHCl3), while the reported values of the samples prepared by resolution or asymmetric synthesis were +/- 64.5-65.6 deg.
- Mori, Kenji,Senda, Shuji
-
p. 541 - 546
(2007/10/02)
-