- Synthesis and cytotoxic activity of N-substituted thiosemicarbazones of 3-(3,4-methylenedioxy) phenylpropanal
-
Five new N-substituted thiosemicarbazones of 3-(3,4-methylenedioxy) phenylpropanal were synthesized. Safrole, a natural product obtained from sassafras oil (Ocotea pretiosa), was oxidized to alcohol using BH3-THF and H2O2, followed by oxidation to aldehyde using pyridinium dichromate (PDC) and condensation with five N-substituted derivatives of thiosemicarbazide. Tests were performed to evaluate the cytotoxic activity with continuous chain KB cells (epidermoide carcinoma of the floor of the mouth). Compounds 5 and 6 showed IC50 values of 1.5 and 4.6 μg/ml, respectively.
- Silva, Maria Joselice E.,Alves, Antonio Jose,Do Nascimento, Silene C.
-
-
Read Online
- VISIBLE-LIGHT MEDIATED ORGANOPHOTOREDOX CATALYTIC DEUTERATION OF AROMATIC AND ALIPHATIC ALDEHYDES
-
Described are methods for preparing a deuterated aldehyde using with a photocatalyst and a hydrogen atom transfer agent in a H2O free solvent comprising D2O and an organic solvent under an inert gas. The methods may be used to convert a wide variety of aldehydes (e.g., aryl, alkyl, or alkenyl aldehydes) to C-1 deuterated aldehydes under mild reaction conditions.
- -
-
Paragraph 0059-0060; 0061-0062
(2021/06/22)
-
- Borane-Catalyzed, Chemoselective Reduction and Hydrofunctionalization of Enones Enabled by B-O Transborylation
-
The use of stoichiometric organoborane reductants in organic synthesis is well established. Here these reagents have been rendered catalytic through an isodesmic B-O/B-H transborylation applied in the borane-catalyzed, chemoselective alkene reduction and formal hydrofunctionalization of enones. The reaction was found to proceed by a 1,4-hydroboration of the enone and B-O/B-H transborylation with HBpin, enabling catalyst turnover. Single-turnover and isotopic labeling experiments supported the proposed mechanism of catalysis with 1,4-hydroboration and B-O/B-H transborylation as key steps.
- Nicholson, Kieran,Langer, Thomas,Thomas, Stephen P.
-
supporting information
p. 2498 - 2504
(2021/04/13)
-
- Three-Component, Interrupted Radical Heck/Allylic Substitution Cascade Involving Unactivated Alkyl Bromides
-
Developing efficient and selective strategies to approach complex architectures containing (multi)stereogenic centers has been a long-standing synthetic challenge in both academia and industry. Catalytic cascade reactions represent a powerful means of rapidly leveraging molecular complexity from simple feedstocks. Unfortunately, carrying out cascade Heck-type reactions involving unactivated (tertiary) alkyl halides remains an unmet challenge owing to unavoidable β-hydride elimination. Herein, we show that a modular, practical, and general palladium-catalyzed, radical three-component coupling can indeed overcome the aforementioned limitations through an interrupted Heck/allylic substitution sequence mediated by visible light. Selective 1,4-difunctionalization of unactivated 1,3-dienes, such as butadiene, has been achieved by employing different commercially available nitrogen-, oxygen-, sulfur-, or carbon-based nucleophiles and unactivated alkyl bromides (>130 examples, mostly >95:5 E/Z, >20:1 rr). Sequential C(sp3)-C(sp3) and C-X (N, O, S) bonds have been constructed efficiently with a broad scope and high functional group tolerance. The flexibility and versatility of the strategy have been illustrated in a gram-scale reaction and streamlined syntheses of complex ether, sulfone, and tertiary amine products, some of which would be difficult to access via currently established methods.
- Bellotti, Peter,Glorius, Frank,Heidrich, Bastian,Huang, Huan-Ming,Pflüger, Philipp M.,Schwarz, J. Luca
-
supporting information
p. 10173 - 10183
(2020/06/27)
-
- Asymmetric Multifunctional Modular Organocatalysis: One-Pot Direct Strategy to Enantiopure α,β-Disubstituted γ-Butyrolactones
-
A simple and efficient approach to enantioenriched α,β-disubstituted γ-butyrolactones has been developed through multifunctional modular organocatalysis in a highly enantioselective (>99% ee) and diastereoselective (>30:1) manner following a one-pot sequential Michael-hemiacetalization-oxidation reaction. The catalytic process has great substrate compatibility, and the products have been transformed to synthetically useful molecules. The methodology has also been applied to the formal synthesis of (+)-Pilocarpine.
- Mahto, Pratibha,Rana, Nirmal K.,Shukla, Khyati,Das, Braja G.,Joshi, Harshit,Singh, Vinod K.
-
supporting information
p. 5962 - 5966
(2019/08/20)
-
- Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage-Independent Activation of Strong C-O Bonds
-
Despite the prevalence of alcohols and carboxylic acids as functional groups in organic molecules and the potential to serve as radical precursors, C-O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen-centered nucleophile. We show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H atom trapping to afford the deoxygenated products. Using the same method, we demonstrate access to synthetically versatile acyl radicals, which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge C-O, C-N, and C-C bonds in a single step.
- Stache, Erin E.,Ertel, Alyssa B.,Rovis, Tomislav,Doyle, Abigail G.
-
p. 11134 - 11139
(2018/11/21)
-
- Pilot in Vivo Structure-Activity Relationship of Dihydromethysticin in Blocking 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone-Induced O6-Methylguanine and Lung Tumor in A/J Mice
-
(+)-Dihydromethysticin was recently identified as a promising lung cancer chemopreventive agent, while (+)-dihydrokavain was completely ineffective. A pilot in vivo structure-activity relationship (SAR) was explored, evaluating the efficacy of its analogs in blocking 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced short-term O6-methylguanine and long-term adenoma formation in the lung tissues in A/J mice. Both results revealed cohesive SARs, demonstrating that the methylenedioxy functional group in DHM is essential while the lactone functional group tolerates modifications.
- Puppala, Manohar,Narayanapillai, Sreekanth C.,Leitzman, Pablo,Sun, Haifeng,Upadhyaya, Pramod,O'Sullivan, M. Gerard,Hecht, Stephen S.,Xing, Chengguo
-
supporting information
p. 7935 - 7940
(2017/10/06)
-
- Asymmetric NHC-catalyzed redox α-amination of α- aroyloxyaldehydes
-
Asymmetric α-amination through an N-heterocyclic carbene (NHC)-catalyzed redox reaction of α-aroyloxyaldehydes with N-aryl-N-aroyldiazenes to form α-hydrazino esters with high enantioselectivity (up to 99% ee) is reported. The hydrazide products are readily converted into enantioenriched N-aryl amino esters through samarium(II) iodide mediated N-N bond cleavage.
- Taylor, James E.,Daniels, David S. B.,Smith, Andrew D.
-
supporting information
p. 6058 - 6061
(2014/01/06)
-
- A natural product inspired tetrahydropyran collection yields mitosis modulators that synergistically target CSE1L and tubulin
-
A Prins cyclization between a polymerbound aldehyde and a homoallylic alcohol served as the key step in the synthesis of tetrahydropyran derivatives. A phenotypic screen led to the identification of compounds that inhibit mitosis (as seen by the accumulation of round cells with condensed DNA and membrane blebs; see picture). These compounds were termed tubulexins as they target the CSE1L protein and the vinca alkaloid binding site of tubulin.
- Voigt, Tobias,Gerding-Reimers, Claas,Tran, Tuyen Thi Ngoc,Bergmann, Sabrina,Lachance, Hugo,Sch?lermann, Beate,Brockmeyer, Andreas,Janning, Petra,Ziegler, Slava,Waldmann, Herbert
-
p. 410 - 414
(2013/02/23)
-
- New two-step sequence involving a hetero-Diels-Alder and a nonphenolic oxidative coupling reaction: A convergent access to analogs of steganacin
-
A new family of analogs of steganacin, an important antimitotic compound, was accessed. It takes advantage of a completely stereoselective sequence of two key steps. The central dihydropyrane core is built by a highly diastereoselective and facially controlled hetero-Diels-Alder reaction. It is followed by a nonphenolic biaryl oxidative coupling with a complete atropo-stereoselectivity. It leads to a quick way to form cyclic biaryl lignans.
- Laurent, Mathieu Y.,Stocker, Vivien,Temgoua, Valéry Momo,Dujardin, Gilles,Dhal, Robert
-
supporting information; experimental part
p. 1608 - 1611
(2011/04/26)
-
- A concise microwave-assisted synthesis of 2-aminoimidazole marine sponge alkaloids of the isonaamines series
-
A short and efficient route to 1,4-substituted 2-aminoim-idazole alkaloids starting from the easily accessible 2-alkylami-nopyrimidines and α-bromo aldehydes is reported. The formation of the intermediate imidazo[l,2-a] pyrimidinium salts and subsequent cleavage were facilitated by microwave irradiation. Marine sponge alkaloids preclathridines A, C and isonaamines A, C, D were obtained in high yields using the optimized one-pot two-step procedure. Thieme Stuttgart.
- Ermolat'ev,Alifanov,Rybakov,Babaev,Van Der Eycken
-
scheme or table
p. 2083 - 2088
(2009/04/03)
-
- Tandem molybdenum catalyzed hydrosilylations: An expedient synthesis of β-aryl aldehydes
-
The synthesis of β-aryl aldehydes utilizing a tandem molybdenum catalyzed hydrosilylation is described. This new functional group interconversion provides an efficient method for the two-carbon homologation of aryl aldehydes.
- Frost, Christopher G.,Hartley, Benjamin C.
-
p. 4259 - 4261
(2008/02/12)
-
- INDUCIBLE NITRIC OXIDE SYNTHASE DIMERIZATION INHIBITORS
-
The present invention relates to compounds and methods useful as inhibitors of nitric oxide synthase. Certain compounds of the subject invention have the following structural formula: wherein T, X, and Y are independently selected from the group consisting of CR4, N, NR4, S, and O; U is selected from the group consisting of CR10 and N; V is selected from the group consisting of CR4 and N; W and W' are independently selected from the group consisting of CH2, CR7R8, NR9, O, N(O), S(O)q and C(O); n, m and p are independently an integer from 0 to 5; q is 0, 1, or 2; and other substituents are as defined herein. Other compounds of the subject invention have structural formulas as defined herein. Also disclosed herein are pharmaceutical compositions comprising the compounds of the subject invention
- -
-
Page/Page column 62
(2010/11/08)
-
- Ruthenium-catalyzed cycloisomerization of cis-3-en-1-ynes to cyclopentadiene and related derivatives through a 1,5-sigmatropic hydrogen shift of ruthenium vinylidene intermediates
-
We report a new ruthenium-catalyzed cycloisomerization of unactivated cis-3-en-1-ynes, which produces substituted cyclopentadiene and related derivatives. The mechanism of this cyclization is proposed to involve a [1,5]-sigmatropic hydrogen shift of ruthenium-vinylidene intermediates on the basis of deuterium-labeling experiments. Copyright
- Datta, Swarup,Odedra, Arjan,Liu, Rai-Shung
-
p. 11606 - 11607
(2007/10/03)
-
- Stereoselective synthesis of naturally occurring unsaturated amide alkaloids by a modified Ramberg-Baecklund reaction
-
A convenient and rapid approach for the synthesis of naturally occurring unsaturated amide alkaloids 1a-1n by the recently developed one-flask Ramberg-Baecklund reaction is described. The starting material was alcohol 3, which was transformed into thiolacetate 4 using the Mitsunobu reaction. In situ cleavage of acetyl moiety of 4, followed by alkylation of the resulting thiol with appropriate chloroacetamide 5, provided the sulfide 6. Oxidation of sulfide 6 gave the corresponding sulfone 2. Treatment of the sulfone 2 with the dibromodifluoromethane in the presence of alumina-supported potassium hydroxide in dichloromethane solution afforded unsaturated amide alkaloids 1a-1n. To the best of our knowledge, the synthesis of 1e and 1i was reported for the first time.
- Li, Yang,Zhang, Yu,Huang, Zhi,Cao, Xiaoping,Gao, Kun
-
p. 622 - 630
(2007/10/03)
-
- Efficient construction of benzohydrindenones from aryltrienones via domino Nazarov electrocyclization - Electrophilic aromatic substitution
-
1,4-Dien-3-ones substituted with pendant arylethyl side chains attached at C-1 were readily prepared from substituted dihydrocinnamaldehydes. Treatment with TiCl4 at low temperature effected domino Nazarov electrocyclization - arene trapping within 5 min to give racemic benzohydrindenones in near-quantitative yield and with complete diastereoselectivity.
- Browder, Cindy C.,Marmsaeter, Fredrik P.,West
-
p. 375 - 385
(2007/10/03)
-
- Three-component synthesis of (E)-α,β-unsaturated amides of the piperine family
-
Selective formation of (E)-α,β-unsaturated amides by intermolecular three-component reaction between aldehydes, amines (1° or 2°) and ketenylidenetriphenylphosphorane (Ph3P=C=C=O) is described. Natural amides such as fagaramide and piperines could be prepared from immediately available educts. The method is shown to be extendable to the preparation of thioesters from thiols and aldehydes.
- Schobert,Siegfried,Gordon
-
p. 2393 - 2397
(2007/10/03)
-
- Highly efficient trapping of the Nazarov intermediate with substituted arenes.
-
1,4-Dien-3-ones bearing pendant arylethyl side chains were readily prepared from substituted dihydrocinnamaldehydes. When treated with TiCl(4) at low temperature, these compounds underwent domino cyclization to give benzohydrindenones in near-quantitative yield and with complete diastereoselectivity. Reaction: see text.
- Browder,Marmsaeter,West
-
p. 3033 - 3035
(2007/10/03)
-
- PCC oxidation of organoboranes obtained using acetoxyborohydride
-
The selective hydroboration with acetoxyborohydride of dienes and functionalized olefins followed by PCC oxidation afford the corresponding carbonyl derivatives.
- Dhillon, Ranjit S.,Kaur, Avinder Pal,Kaur, Gurpreet
-
p. 453 - 454
(2007/10/03)
-
- Synthesis of piperamides and new analogues from natural safrole
-
Species of the Piper genus are amply known for their biological activities. This paper describes a new synthetic route for the preparation of piperamides and analogues, using as an efficient precursor, the Brazilian natural product safrole (1). The amides (6a-c) were obtained in 25-32% overall yield.
- De Araújo Jr., Jo?o X.,Barreiro, Eliezer J.,Parente, José P.,Fraga, Carlos A. M.
-
p. 263 - 273
(2007/10/03)
-
- Parallel synthesis of aldehydes and ketone facilitated by a new solid- phase Weinreb amide
-
This paper describes a novel supported Weinreb amide resin that facilitates parallel synthesis of aldehydes and ketones on a scale useful for chemical library synthesis. This new resin makes it possible to produce custom aldehydes and ketones from a wide range of carboxylic acids, including N-BOC-amino acids. A variety of commercially unavailable aldehydes are easily synthesized in parallel and obtained in high purity via a simple filtration workup, thus facilitating parallel synthesis of lead optimization libraries that typically require custom synthesis of aldehyde intermediates for development of structure-activity relationships. To demonstrate the utility of this method, we synthesized a small library based on a supported Horner- Emmons reagent. This is the first time it has been shown that aldehydes generated via a supported Weinreb amide could be used directly as reagents in chemical library synthesis employing moisture-sensitive reactions. The analogous solution reaction is not suited for parallel synthesis because of the laborious extractive workup procedure necessary and, at times, the instability of these reactive intermediates.
- Salvino, Joseph M.,Mervic, Miljenko,Mason, Helen J.,Kiesow, Terence,Teager, David,Airey, John,Labaudiniere, Richard
-
p. 1823 - 1830
(2007/10/03)
-
- Thieno-pyridine sulfonamides derivatives thereof and related compounds that modulate the activity of endothelin
-
Methods, compositions, and compounds for modulating the activity of an endothelin peptide are provided. The methods use compositions that contain compounds that include those of the formula: STR1 where X is selected from groups that include O, S, and NH; Y is selected from O+ and N, and R1 and R2 are each selected independently from among alkyl, lower alkenyl, lower alkynyl, lower haloalkyl, halide, pseudohalide or H, except that R2 is not halide. R3, R4 and R5 are selected from among groups that include hydrogen, halide, alkoxy, alkyl, haloalkyl; and R7 is selected from groups that include (CH2)r R18, in which r is 0 to 6 and R18 is selected from groups that include aryl, particularly pyrmidinyl and phenyl. The methods are effected by contacting endothelin receptors with one or more of the compounds or with compositions containing one or more of the compounds prior to, simultaneously with, or subsequent to contacting the receptors with an endothelin peptide.
- -
-
-
- Total synthesis of isodeoxypodophyllotoxin using the Me3Sn radical initiated carbocyclization
-
The lactone portion of the podophylotoxin framework was assembled from a free-radical carbocyclization reaction, and the target structure was constructed based on intramolecular Friedel-Crafts reaction. In addition to isodeoxypodophyllotoxin, there were formed unusual tri- and tetracyclic compounds.The lactone portion of the podophylotoxin framework was assembled from a free-radical carbocyclization reaction, and the target structure was constructed based on intramolecular Friedel-Crafts reaction. In addition to isodeoxypodophyllotoxin, there were formed unusual tri- and tetracyclic compounds.
- Hanessian, Stephen,Ninkovic, Sacha
-
p. 1880 - 1888
(2007/10/03)
-
- A SHORT AND CONVENIENT SYNTHESIS OF (2E,4E)-N-ISOBUTYL-7-(3,4-METHYLENEDIOXYPHENYL)HEPTA-2,4-DIENAMIDE
-
(2E,4E)-N-Isobutyl-7-(3,4-methylenedioxyphenyl)hepta-2,4-dienamide (I) possessing insecticidal activity against flies and mosquitoes has been synthesized in fine yield from 3-(3,4-methylenedioxyphenyl)prop-1-ene (II) using hydroboration-oxidation with acetoxyborohydride and a modified Wittig reaction as the key steps.
- Kad, Goverdhan L.,Arora, Ajay K.,Singh, Sukhwinder,Singh, Jasvinder
-
p. 1050 - 1053
(2007/10/03)
-
- Synthetic Routs to the Piperolides, Faydenolides, Epoxypiperolides, and Related Compounds
-
Syntheses of the piperolides, the faydenolides, epoxypiperolide, and related compounds are described. (+/-)-Narthogenin is also efficiently produced.
- Pelter, Andrew,Al-Bayati, Redha I. H.,Ayoub, Miqdad T.,Lewis, Wynn,Pardasani, Pushpa,Hansel, Rudolf
-
p. 717 - 742
(2007/10/02)
-
- ORGANOBORANES FOR SYNTHESIS. 4. OXIDATION OF ORGANOBORANES WITH PYRIDINIUM CHLOROCHROMATE. A DIRECT SYNTHESIS OF ALDEHYDES FROM TERMINAL ALKENES VIA HYDROBORATION
-
The oxidation of trialkylboranes containing primary alkyl groups with pyridinium chlorochromate (PCC) in methylene chloride provides the corresponding aldehydes in good yields.The stoichiometry for the oxidation of alcohols, borate esters and trialkylboranes with PCC has been examined.In view of the poor regioselectivity (only 94percent primary alkyl groups) and functional group tolerance observed in the hydroboration with borane (BH3*THF or BH3*SMe2), a more selective hydroborating agent, bis(3-methyl-2-butyl)borane (disiamylborane), was utilized for the preparation of aldehydes from terminal alkenes.However, the formation of 3-methyl-2-butanone as a by-product, and the requirement of six moles of PCC per mole of aldehyde are major disadvantages in this method.This difficulty was circumvented by employing monochloroborane-dimethyl sulfide for hydroboration.This reagent exhibits high regioselectivity (> 99percent primary alkyl groups) in the hydroboration of terminal alkenes.Oxidation of the resulting dialkylchloroborane following hydrolysis affords the desired aldehydes in satisfactory yields.Consequently, the hydroboration of terminal alkenes, followed by PCC oxidation, represents a direct convenient method for the transformation of alkenes into the corresponding aldehydes.
- Brown, Herbert C.,Kulkarni, Surendra U.,Rao, C. Gundu,Patil, Vemanna D.
-
p. 5515 - 5522
(2007/10/02)
-