- Asymmetric Total Syntheses of Kopsia Indole Alkaloids
-
The asymmetric total syntheses of a group of structurally complex Kopsia alkaloids, (?)-kopsine, (?)-isokopsine, (+)-methyl chanofruticosinate, (?)-fruticosine, and (?)-kopsanone, has been achieved. The key strategies for the construction of the molecular complexity in the targets included an asymmetric Tsuji–Trost rearrangement to set the first quaternary carbon center at C20, an intramolecular cyclopropanation by diazo decomposition to install the second and third quaternary carbon centers at C2 and C7, respectively, and a SmI2-promoted acyloin condensation to assemble the isokopsine core. A radical decarboxylation of an isokopsine-type intermediate results in a thermodynamic partial rearrangement to give N-decarbomethoxyisokopsine and N-decarbomethoxykopsine, two key intermediates for the syntheses of Kopsia alkaloids with different subtype core structures.
- Leng, Lingying,Zhou, Xiaohan,Liao, Qi,Wang, Falu,Song, Hao,Zhang, Dan,Liu, Xiao-Yu,Qin, Yong
-
-
Read Online
- Conformationally constrained penta(hetero)cyclic molecular architectures by photoassisted diversity-oriented synthesis
-
Intramolecular cycloadditions of photogenerated azaxylylenes provide access to unprecedented polyheterocyclic scaffolds, which are suitable for subsequent postphotochemical modifications to further grow molecular complexity. Here, we explore approaches to the rapid "assembly" of new photoprecursors with nitrogen- or oxygen-rich tethers capable of producing potential pharmacophores and also compatible with subsequent 1,3-dipolar cycloadditions to furnish pentacyclic heterocycles with new structural cores, a minimal number of rotatable bonds, and a high content of sp3-hybridized carbon atoms. The modular assembly of the photoprecursors and the potential variety of postphotochemical modifications of the primary photoproducts provide a framework for the combinatorial implementation of this synthetic strategy.
- Umstead, Weston J.,Mukhina, Olga A.,Kutateladze, Andrei G.
-
-
Read Online
- Total Synthesis of Actinophyllic Acid
-
Herein we report a total synthesis of the indolohydroazocine natural product actinophyllic acid. The target molecule was retrosynthetically deconvoluted to render a greatly simplified and symmetrical [4.4.1] bicyclic trienone, the desymmetrization of which was carefully examined under a variety of conditions, including oxidative, reductive, and transition-metal-catalyzed transformations. Ultimately, the successful synthetic strategy featured chemoselective catalytic dihydroxylation, desymmetrizing nitrile oxide dipolar cycloaddition, and palladium-catalyzed aminoarylation to sequentially modify the three olefins within the trienone, followed by a late-stage reductive cascade indolization and alkylation to complete the target molecule.
- Yoshii, Yu,Tokuyama, Hidetoshi,Chen, David Y.-K.
-
-
Read Online
- Three-dimensional heterocycles: New uracil-based structures obtained by nucleophilic substitution at the sp2 carbon of bromoisoxazoline
-
The regioisomeric cycloadducts of bromonitrile oxide and N-benzoyl-2,3-oxazanorborn- 5-ene were easily prepared and elaborated into a novel class of uracil-based scaffolds. The key-synthetic step is the nucleophilic substitution at the sp2 carbon atom of the bromoisoxazoline three-dimensional heterocycles. The protocol to perform the nucleophilic substitution of uracil anions was optimized and adapted to the steric requirements of the substrates. A library of pyrimidine derivatives was prepared in very good yields and the products were fully characterized. They are proposed as nucleoside analogues and as synthons for β-turn motifs within PNA structures.
- Memeo, Misal Giuseppe,Lapolla, Francesco,Bovio, Bruna,Quadrelli, Paolo
-
-
Read Online
- Synthetic method 3 - bromo -5, 5 - dimethyl -4 and 5 -dihydroisoxazole
-
The invention discloses a synthetic method of 3 - bromo -5, 5 - dimethyl -4 and 5 -dihydroisoxazole, which comprises the continuous synthesis of intermediate dibromoformaldehyde oxime and the synthesis of the product 3 - bromo -5, 5 - dimethyl -4 and 5 -dihydroisoxazole. To the method, the production route is improved firstly through dehydration condensation of glyoxylic acid and hydroxylamine hydrochloride, the obtained intermediate does not need to be discharged, and a bromination reagent is directly added. 1,3 - Dipole ring addition reaction produces the target product, can realize whole production route in-process target product overall yield's improvement, reduces by-product and the generation of three wastes, can also realize the recovery of solvent, and easy and simple to handle, and whole process used raw materials and solvent price are low, are favorable to the control cost, especially be fit for industrial production.
- -
-
Paragraph 0018-0023
(2021/12/08)
-
- Preparation method of pyroxasulfone intermediate
-
The invention discloses a preparation method of a pyroxasulfone intermediate, which comprises the following steps: by taking glyoxylic acid as an initial raw material, carrying out condensation reaction on the glyoxylic acid and hydroxylamine to generate 2-(hydroxyimino) acetic acid; then carrying out bromination reaction in the presence of sodium bromate and sodium hydrogen sulfite to generate dibromoformaldoxime; and finally, carrying out cyclization reaction with isobutene to generate the pyroxasulfone intermediate that is 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole. The bromination reaction temperature is 10-60 DEG C, and the molar ratio of glyoxylic acid to sodium bromate to sodium hydrogen sulfite is 1: 2-1: 4. According to the method disclosed by the invention, the bromine is slowly released through the reaction of the sodium bromate and the sodium hydrogen sulfite, the reaction is relatively mild and easy to control, byproducts are not easy to generate, the product generated by introducing isobutene does not need to be rectified to remove impurities, and the yield is relatively high.
- -
-
Paragraph 0009; 0025-0029
(2021/09/04)
-
- Synthesis method and application of pyroxasulfone
-
The invention relates to the technical field of pesticides, and provides a synthesis method of pyroxasulfone, which comprises the steps of: (1) carrying out a hydroxyalkylation reaction, a fluoromethylation reaction and a chlorination reaction on a reaction body (I) to obtain an intermediate 2; and (2) mixing an intermediate 1 and the intermediate 2, adding water to separate out an organic phase to obtain a transition intermediate, and adding a solvent and an oxidizing agent for reaction to obtain pyroxasulfone. The invention further provides application of pyroxasulfone to pesticides. The pyroxasulfone is prepared by the synthesis method. According to the invention, the overall yield of the target product can be increased, the generation of by-products can be reduced, the generation of three wastes is perfectly reduced, and the recycling of the solvent is realized.
- -
-
Paragraph 0030; 0091; 0097-0197
(2020/09/09)
-
- PROCESS FOR PREPARATION OF BROMO FORMIMINE COMPOUNDS
-
The present invention discloses an improved process for the preparation of bromo-formimine compounds. More particularly, the present invention discloses an improved process for the preparation of bromo-formimine compounds, wherein bromine anion is recycled by using a suitable oxidizing agent.
- -
-
Page/Page column 16-17
(2020/12/11)
-
- Synthesis and Synthetic Application of Chloro- And Bromofuroxans
-
Furoxans are potentially useful heteroaromatic units in pharmaceuticals and agrichemicals. However, the applications for furoxan-based compounds have been hampered due to the underdevelopment of their synthetic methods. Herein, we report a new synthetic approach for the synthesis of chloro- and bromofuroxans. The starting materials were dichloro- and dibromofuroxans, and the substituents were directly introduced to the furoxan ring in a modular fashion. The synthesized monohalofuroxans served as substrates for the installation of a second substituent to prepare further functionalized furoxans.
- Ando, Akihiro,Hasebe, Hayu,Hayashi, Masahiko,Kim, Hojin,Matsubara, Ryosuke,Tsuneda, Takao
-
p. 5959 - 5972
(2020/05/26)
-
- In vivo evaluation of two tissue transglutaminase PET tracers in an orthotopic tumour xenograft model
-
Background: The protein cross-linking enzyme tissue transglutaminase (TG2; EC 2.3.2.13) is associated with the pathogenesis of various diseases, including cancer. Recently, the synthesis and initial evaluation of two high-potential radiolabelled irreversible TG2 inhibitors were reported by us. In the present study, these two compounds were evaluated further in a breast cancer (MDA-MB-231) tumour xenograft model for imaging active tissue transglutaminase in vivo. Results: The metabolic stability of [11C]1 and [18F]2 in SCID mice was comparable to the previously reported stability in Wistar rats. Quantitative real-time polymerase chain reaction analysis on MDA-MB-231 cells and isolated tumours showed a high level of TG2 expression with very low expression of other transglutaminases. PET imaging showed low tumour uptake of [11C]1 (approx. 0.5 percentage of the injected dose per gram (%ID/g) at 40–60?min p.i.) and with relatively fast washout. Tumour uptake for [18F]2 was steadily increasing over time (approx. 1.7 %ID/g at 40–60?min p.i.). Pretreatment of the animals with the TG2 inhibitor ERW1041E resulted in lower tumour activity concentrations, and this inhibitory effect was enhanced using unlabelled 2. Conclusions: Whereas the TG2 targeting potential of [11C]1 in this model seems inadequate, targeting of TG2 using [18F]2 was achieved. As such, [18F]2 could be used in future studies to clarify the role of active tissue transglutaminase in disease.
- van der Wildt, Berend,Wilhelmus, Micha M. M.,Beaino, Wissam,Kooijman, Esther J. M.,Schuit, Robert C.,Bol, John G. J. M.,Breve, John J. P.,Pasternack, Ralf,Lammertsma, Adriaan A.,Windhorst, Albert D.,Drukarch, Benjamin
-
-
- Continuous Preparation and Use of Dibromoformaldoxime as a Reactive Intermediate for the Synthesis of 3-Bromoisoxazolines
-
We report the multistep continuous process for the preparation of dibromoformaldoxime (DBFO) as a precursor to generate 3-bromoisoxazolines. We also report process improvements that afford a productivity of over 620 mmol h-1 of DBFO.
- Battilocchio, Claudio,Bosica, Francesco,Rowe, Sam M.,Abreu, Bruna L.,Godineau, Edouard,Lehmann, Matthias,Ley, Steven V.
-
supporting information
p. 1588 - 1594
(2017/10/25)
-
- Synthesis of spiro 3-bromo-4,5-dihydroisoxazoles via [1,3]dipolar cycloaddition reactions
-
A group of novel 4-bromo-7,9-dimethyl-1-aryl-2-oxa-3,7,9-triaza-spiro[4.5]dec-3-ene-6,8,10-trione derivatives is prepared through 1,3-dipolar cycloadditions between benzylidenes and bromonitrile oxide. This reaction is shown to have high atom economy.
- Soleimani, Ebrahim,Yazdani, Hossein,Saei, Parisa
-
supporting information
p. 1635 - 1637
(2015/03/14)
-
- Discovery of a novel isoxazoline derivative of prednisolone endowed with a robust anti-inflammatory profile and suitable for topical pulmonary administration
-
A novel glucocorticoids series of (GCs), 6α,9α-di-Fluoro 3-substituted C-16,17-isoxazolines was designed, synthesised and their structure-activity relationship was evaluated with glucocorticoid receptor (GR) binding studies together with GR nuclear translocation cell-based assays. This strategy, coupled with in silico modelling analysis, allowed for the identification of Cpd #15, an isoxazoline showing a sub-nanomolar inhibitory potency (IC50 = 0.84 nM) against TNFα-evoked IL-8 release in primary human airways smooth muscle cells. In Raw264.7 mouse macrophages, Cpd #15 inhibited LPS-induced NO release with a potency (IC50 = 6 nM) > 10-fold higher with respect to Dexamethasone. Upon intratracheal (i.t.) administration, Cpd #15, at 0.1 μmol/kg significantly inhibited and at 1 μmol/kg fully counteracted eosinophilic infiltration in a model of allergen-induced pulmonary inflammation in rats. Moreover, Cpd #15 proved to be suitable for pulmonary topical administration given its sustained lung retention (t1/2 = 6.5 h) and high pulmonary levels (>100-fold higher than plasma levels) upon intratracheal administration in rats. In summary, Cpd #15 displays a pharmacokinetic and pharmacodynamic profile suitable for topical treatment of conditions associated with pulmonary inflammation such as asthma and COPD.
- Ghidini,Capelli,Carnini,Cenacchi,Marchini,Virdis,Italia,Facchinetti
-
supporting information
p. 88 - 95
(2015/02/05)
-
- Design, synthesis and biological evaluation of B-region modified diarylalkyl amide analogues as novel TRPV1 antagonists
-
Design, synthesis and biological evaluation of B-region, known to be a dipolar interacting pharmacophore, modified diarylalkyl amide analogues for novel TRPV1 (transient receptor potential channel, vanilloid subfamily member 1) antagonists was described. A variety of moieties including guanidines, heterocyclic rings, cinnamides, and α-substituted acetamides were introduced at the B-region. TRPV1 antagonistic activities of these analogues were evaluated by 45Ca2+ uptake assay in rat DRG neuron. In particular, α,α-difluoroamide 53 exhibited 3-fold more potent TRPV1 antagonistic activity (IC50 = 0.058 μM) than the parent amide analogue 6.
- Han, Young Taek,Yang, Shao-Mei,Wang, Xiao-Yuan,Li, Fu-Nan
-
p. 440 - 451
(2014/04/17)
-
- Synthesis and molecular modeling of novel dihydroxycyclopentane- carbonitrile nor-nucleosides by bromonitrile oxide 1,3-dipolar cycloaddition
-
The regioisomeric cycloadducts of the bromonitrile oxide to the N-benzoyl-2,3-oxazanorborn-5-ene were easily prepared and elaborated into a novel class of uracil nor-nucleoside derivatives. In the key-synthetic step represented by the reductive N-O bond cleavage, an unusual double ring opening afforded the aminol intermediates containing a β-hydroxynitrile structure. By adapting known protocols, the aminols entered the linear construction of uracil rings. These novel nucleosides were found structurally similar to a potent antiviral compound, Brivudin, and molecular modeling and docking allowed to select one of the two regioisomeric structures as promising candidate for antiviral tests, due to the nice level of binding with the Thymidine Kinase, the enzyme involved in virus replication.
- Savion, Marco,Memeo, Misal Giuseppe,Bovio, Bruna,Grazioso, Giovanni,Legnani, Laura,Quadrelli, Paolo
-
experimental part
p. 1845 - 1852
(2012/03/27)
-
- ISOXAZOLE-PYRIDINE DERIVATIVES AS GABA MODULATORS
-
The present invention is concerned with novel isoxazole derivatives of formula (I) wherein X, R1, R2, R3 and R4 are as described herein, as well as pharmaceutically acceptable salts and esters thereof. The active compounds of the present invention have affinity and selectivity for GABA A α5 receptor. Further the present invention is concerned with the manufacture of the active compounds of formula (I), pharmaceutical compositions containing them and their use as medicaments.
- -
-
Page/Page column 51
(2010/11/18)
-
- The biological targets of acivicin inspired 3-chloro- and 3-bromodihydroisoxazole scaffolds
-
Target analysis of acivicin derived 3-halodihydroisoxazoles scaffolds in living non-pathogenic and pathogenic bacteria.
- Orth, Ronald,Boettcher, Thomas,Sieber, Stephan A.
-
supporting information; experimental part
p. 8475 - 8477
(2011/02/24)
-
- Design, synthesis, and herbicidal activities of novel 2-cyanoacrylates containing isoxazole moieties
-
A series of novel 2-cyanoacrylates containing an isoxazole moiety were designed and synthesized. Their structures were characterized by 1H NMR and elemental analysis (or high-resolution mass spectrometry). Their herbicidal activities against four species were evaluated, and the results indicated that some of the title compounds showed excellent herbicidal activities against rape and amaranth pigweed in postemergence treatment even at a dose of 75 g/ha.
- Liu, Yuxiu,Cui, Zhipeng,Liu, Bin,Cai, Baoli,Li, Yonghong,Wang, Qingmin
-
scheme or table
p. 2685 - 2689
(2011/07/07)
-
- NOVEL HETEROCYCLIC COMPOUNDS AS POSITIVE ALLOSTERIC MODULATORS OF METABOTROPIC GLUTAMATE RECEPTORS
-
The present invention relates to new compounds which are Heterocyclic derivatives of formula (I) wherein A, B, P, X, Y, Q, W, R1 and R2 are defined in the description. Invention compounds are useful for treating central or peripheral nervous system disorders and other disorders which are affected by the neuromodulatory effect of mGluR5 positive allosteric modulators such as cognitive decline and also to treat both positive and negative symptoms in schizophrenia.
- -
-
Page/Page column 54-55
(2010/11/25)
-
- Sulfonamide derivatives
-
The present invention provides certain sulfonamide derivatives useful for potentiating glutamate receptor function in a mammal and therefore, useful for treating a wide variety of conditions, such as psychiatric and neurological disorders.
- -
-
-
- Synthesis of haloformimine compounds
-
Disclosed is an improved method for the preparation of highly pure haloformimine compounds in high yields by reacting a formimine compound in a solvent with a halogenating agent while maintaining the pH of the halogenation reaction in the range of 2 to 5. The pH of the reaction may be maintained by a variety of means, such as by the addition of a base.
- -
-
-
- Sulphonamide derivatives
-
Glutamate receptor function in a mammal may be potentiated using an effective amount of a compound of formulaR1—L—NHSO2R2??Iin whichR1 represents an unsubstituted or substituted aromatic or heteroaromatic group;R2 represents (1-6C)alkyl, (3-6C)cycloalkyl, (1-6C)fluoroalkyl, (1-6C)chloroalkyl, (2-6C)alkenyl, (1-4C)alkoxy(1-4C)alkyl, phenyl which is unsubstituted or substituted by halogen, (1-4C)alkyl or (1-4C)alkoxy, or a group, of formula R3R4N in which R3 and R4 each independently represents (1-4C)alkyl or, together with the nitrogen atom to which they are attached form an azetidinyl, pyrrolidinyl, piperidinyl, morpholino, piperazinyl, hexahydroazepinyl or octahydroazocinyl group; andL represents a (2-4C)alkylene chain which is unsubstituted or substituted by one or two substituents selected independently from (1-6C)alkyl, aryl(1-6C)alkyl, (2-6C)alkenyl, aryl(2-6C)alkenyl and aryl, or by two substituents which, together with the carbon atom or carbon atoms to which they are attached form a (3-8C)carbocyclic ring;and pharmaceutically acceptable salts thereof.Also disclosed are compounds of formula I, processes for preparing them and pharmaceutical compositions containing them.
- -
-
-
- Synthesis and pharmacological profile of a series of 2,5-substituted-N,N-dimethyltryptamine derivatives as novel antagonists for the vascular 5-HT1B-like receptor
-
The coronary 5-HT1B-like receptor has been implicated in vasospasm and it is postulated that a 5-HT1B-like antagonist may block the detrimental action of 5-HT whilst not interfering with normal blood vessel function. The synthesis and pharmacological profile of a novel series of 2-(N-heteroaryl)carboxamido-5-substituted-N,N-dimethyltryptamine derivatives as silent (as judged by the inability of angiotensin II to unmask 5-HT1B-like receptor mediated agonist activity in the rabbit femoral artery), competitive and selective 5-HT1B-like receptor antagonists is described. Modifications to the 2-carboxamido sidechain as well as the 5-ethylene linked heterocycle are explored. N-Furfuryl-5-[2-(N-phthalimido)ethyl]-3-[2-(dimethylamino)ethyl]-1H-indole-2- carboxamide (34) was discovered which fulfilled our in vitro selection criteria and which had a favourable pharmacokinetic profile. Compound 34 showed good affinity (pKB = 7.38) for the vascular 5-HT1B-like receptor and greater than 125 fold selectivity over α1-adrenoceptor affinity. The selectivity of 34 and related compounds for the 5-HT1B-like receptor over other receptor subtypes is discussed and a mode of binding for this class of compound to a pharmacophore model is proposed. The Royal Society of Chemistry 1999.
- Moloney, Gerard P.,Martin, Graeme R.,Mathews, Neil,Hobbs, Heather,Dodsworth, Susan,Sang, Pang Yih,Knight, Cameron,Maxwell, Miles,Glen, Robert C.
-
p. 2713 - 2723
(2007/10/03)
-
- An expedient synthesis of (±)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid hydrobromide via a 3-bromoisoxazole intermediate
-
The excitatory, amino acid ± 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid hydrobromide was prepared in gram quantities in a 3.3% overall yield from methylbut 2-ynoate. The key step was the facile preparation of methyl 3-bromo-5-methylisoxazole-4-carboxylate.
- Hanson, Robert N.,Mohamed, Fand A.
-
p. 345 - 348
(2007/10/03)
-
- Synthesis of α-Amino-3-chloro-4,5-dihydro-5-methyl-5-isoxazoleacetic Acid, a Ring-Methylated Analogue of the Antitumor Agent Acivicin (AT-125)
-
α-Amino-3-chloro-4,5-dihydro-5-methyl-5-isoxazoleacetic acid (8), a ring-methylated analogue of the potent antitumor agent acivicin (AT-125), is synthesized in a 6-step procedure in 63percent overall yield from (S)-valine.Key step is the 1,3-dipolar addition of bromonitrile oxide to the N,C-protected (S)-isodehydrovaline (6) available from (S)-valine in four steps involving the photoisomerization of N-phthaloylvaline methyl ester (1).The stereochemical course of the 1,3-dipolar cycloaddition is proven by means of a X-ray structure analysis of the major diastereoisomer 7a formed in the chloronitrile oxide cycloaddition.The absolute configuration of the major (u) diastereomer 7a and the bromo derivative 7b is (αS,5R). - Key Words: Acivicin / Photochemistry / 1,3-Dipolar cycloadditions / Nitrile oxides
- Griesbeck, Axel G.,Hirt, Joachim,Peters, Karl,Peters, Eva-Maria,Schnering, Hans-Georg von
-
p. 619 - 624
(2007/10/02)
-
- Pesticidal compounds
-
Compounds of the formula: STR1 wherein R1 is hydrogen or alkyl; Q is a linkage group of the formula --CHR2 -- or --CHR3 --CHR4 --where R2 is hydrogen or alkyl, R3 is hydrogen or alkyl, and R4 is hydrogen or alkyl; X is nitrogen or =CH--; and Z is halogen, show insecticidal activity. Also disclosed are the processes for producing the compounds and methods of using them as insecticides.
- -
-
-
- BROMONITRILE OXIDE CYCLOADDITIONS IN WATER
-
Bromonitrile oxide can be generated homogeneously in water at acidic pH, allowing efficient cycloaddition with water soluble olefins and acetylenes.Allylammonium salts react with high regioselectivity and without the need for N-group protection. Keyword: Acivicin; transglutaminase; cysteine; 4,5-dihydroisoxazole; dibromonoformaldoxime.
- Rohloff, John C.,Robinson, James III,Gardner, John O.
-
p. 3113 - 3116
(2007/10/02)
-
- Diastereofacial Selectivity Studies on 3-Alkenyl-4,5-diphenyl-4,5-dihydroisoxazoles
-
Epoxidation of 3-(1-phenylethenyl)-4,5-diphenyl-4,5-dihydroisoxazole and 3-ethenyl-4,5-diphenyl-4,5-dihydroisoxazole occurred with 74percent diastereomer excess (de) and 66percent de, respectively.Catalytic cis-hydroxylation of the 3-(1-phenylethenyl)dihydroisoxazole afforded a diol with 80percent de.Cycloaddition reactions of the same alkenyl dihydroisoxazoles with bromonitrile oxide and phenylsulfonylcarbonitrile oxide occurred with 10-46percent de; opposite diastereomers were preferred in the reactions of 3-ethenyl- and 3-(1-phenylethenyl)dihydroisoxazoles.These results are rationalized based on a combination of two factors: a preference for the s-trans heterodiene conformer and a preference for attack anti to the C-4 phenyl group in all but one case.The s-trans conformer of 3-ethenyl-4,5-dihydroisoxazole was determined by the ab initio method to be 2.8 kcal/mol more stable than the s-cis conformer.
- Wade, Peter A.,Bereznak, James F.,Palfey, Bruce A.,Carroll, Patrick J.,Dailey, William P.,Sivasubramanian, S.
-
p. 3045 - 3051
(2007/10/02)
-
- Carboxy- and Cyano-Hydroxylation of Alkenes. - Synthesis of 3-Hydroxy-4-amino Acids and Butyrolactones via the Isoxazoline Route
-
Dichloro- and dibromoformaldoximes are useful 1,3-dipolar cycloaddition reagents.They are conveniently preparated in situ, in high yields by dihalogenation of glyoxalic acid aldoxime with N-bromo- and N-chlorosuccinimide or tert-butyl hypochlorite.Dehydrohalogenation with potassium hydrogen carbonate in the presence of alkenes gives 3-halo-isoxazolines in a one-pot reaction.Reduction with iron pentacarbonyl gives β-hydroxynitriles.Methoxylation and catalytic reduction give β-hydroxy esters.Allyl alcohols and allylamines are transformed with halonitrile oxides into butyrolactones (DL-angelica lactone) and DL-3-hydroxy-4-amino acids (carnitine, 4-amino-3-hydroxybutyric acid), respectively.The lactonization is best effected by heating the γ-silyloxy ester in acetic acid with potassium hydrogen sulfate as catalyst.A synthesis of N-Boc-dihydromuscimol is described.
- Halling, Karen,Thomsen, Ib,Torssell, Kurt B. G.
-
p. 985 - 990
(2007/10/02)
-
- Dihaloformaldoxime
-
Dihaloformaldoximes of the formula: STR1 wherein R, X, X1 and Y are as defined herein having biocidal, fungicidal and pesticidal activity are disclosed.
- -
-
-
- Intermediates for the production of epipodophyllotoxin and related compounds and processes for the preparation and use thereof
-
There is provided a novel and efficient stereoselective total synthesis of epipodophyllotoxin and related epipodophyllotoxin compounds of the general formula STR1 wherein R1 and R2 each are independently hydrogen or (lower)alkoxy, or R1 and R2, taken together, is methylenedioxy; R4 and R6 each are independently hydrogen or (lower)alkoxy; and R5 is hydrogen or a phenol-protecting group; or an acid addition salt thereof. The present invention also provides novel intermediates and processes for the preparation of said intermediates, which are then converted into known antineoplastic agents.
- -
-
-
- Trichloroethanimidic acid esters
-
New and more efficient chemical processes are provided for preparing (αS, 5S)-α-amino-3-chloro-2-isoxazoline-5-acetic acid (AT-125), (αS, 5S)-α-amino-3-bromo-2-isoxazoline-5-acetic acid (bromo AT-125) and the C-5 epimers thereof. The disclosed processes allow the above-mentioned antitumor agents to be produced in high yield and purity with substantially fewer steps than prior art chemical procedures.
- -
-
-