- Chelation, activation, and proximity effects in the deprotection of dithianes with ZnBr2. Applications in the polyketide field
-
(Matrix presented) Double deprotection of dithiane aldol equivalents is feasible under mild conditions with ZnBr2 and suitably placed MEM, BOM, and SEM groups which function as protecting, activating, and regiodirecting groups. The procedure is useful in natural product synthesis.
- Vakalopoulos,Hoffmann
-
-
Read Online
- Method for preparing 3, 4-dimethylpyrazole and phosphate thereof
-
The invention discloses a method for preparing 3, 4-dimethylpyrazole and phosphate thereof. The method for preparing the 3, 4-dimethylpyrazole includes the steps: (1) feeding 2-butanone, aldehyde andalkali solution into a microchannel reactor and performing aldehyde ketone condensation reaction to produce 4-hydroxy-3-methyl-2-butanone salt; (2) mixing reaction liquid obtained in the step (1) andacid liquid in the microchannel reactor to obtain 4-hydroxy-3-methyl-2-butanone water solution; (3) performing reaction on hydrazine hydrate and the 4-hydroxy-3-methyl-2-butanone water solution in themicrochannel reactor, mixing reaction liquid with the alkali solution and hydrogen peroxide, and performing oxidative dehydrogenation reaction to obtain 3, 4-dimethylpyrazole water solution; (4) performing organic extraction and distillation on the 3, 4-dimethylpyrazole water solution to obtain the 3, 4-dimethylpyrazole. According to the method, reaction time is greatly shortened, the yield and the purity of products are ensured, and continuous production can be realized.
- -
-
Paragraph 0096; 0098; 0099; 0107; 0115; 0123
(2019/04/17)
-
- DITHIOLAN-3-YLPENTANOATE DERIVATIVES, PHARMACEUTICAL COMPOSITIONS AND METHODS FOR THE TREATMENT OF PAIN
-
The disclosure herein provides 1-carbamoyloxyethyl 5-(1,2-dithiolan-3-yl)pentanoate derivatives of formula I, formula II and formula III. The disclosure also provides a method of synthesizing the compound of formula I, formula II and formula III. The compound of formula I, formula II and formula III or its pharmaceutical acceptable salts, as well as polymorphs, solvates, and hydrates, thereof may be formulated as pharmaceutical composition. The pharmaceutical composition of compound of formula I, formula II and formula III or the final compound of formula I, formula II or formula III may be formulated for non-invasive peroral, topical (example transdermal), enteral, transmucosal, targeted delivery, sustained release delivery, delayed release, pulsed release and parenteral methods. Such compositions may be used to treat chronic pain manifested with chronic diseases or its associated complications.
- -
-
Page/Page column 12; 13
(2015/09/23)
-
- COMPOUND AND METHOD FOR THE TREATMENT OF PAIN
-
The disclosure herein provides a compound of formula 1. The disclosure also provides a method of synthesizing the compound of formula 1. The compound of formula 1 or its pharmaceutical acceptable salts, as well as polymorphs, solvates, and hydrates thereof may be formulated as pharmaceutical composition. The pharmaceutical composition of compound of formula 1 or the final compound may be formulated for non-invasive peroral, topical (example transdermal), enteral, transmucosal, targeted delivery, sustained release delivery, delayed release, pulsed release and parenteral methods. Such compositions may be used to treat chronic pain manifested with chronic diseases or its associated complications.
- -
-
Page/Page column 9
(2011/10/12)
-
- Synthesis of tetrahydrofurans by a tandem hydrogen atom abstraction/ radical nucleophilic displacement sequence
-
(equation presented) The reaction of a series of 5-(N-phthalimidoxy)-1-phenyl-1-(diphenylphosphatoxy)pentanes with triphenyltin hydride and AIBN provides alkoxy radicals which undergo 1,5-hydrogen atom abstraction to give β-(phosphatoxy)alkyl radicals. These radicals then take part in a radical nucleophilic displacement leading, after chain transfer, to tetrahydrofurans.
- Crich, David,Huang, Xianhai,Newcomb, Martin
-
p. 225 - 227
(2008/02/12)
-
- Porphyrins with exocyclic rings. Part 12. Synthesis of meso,β-butano- and meso,β-pentanoporphyrins from cycloalka[b]pyrroles
-
Pyrroles 5 with b-face fused seven- or eight-membered carbocyclic rings were prepared in good yields by Knorr-type condensations with cycloheptanone or cyclooctanone, respectively. Treatment with lead tetraacetate in dichloromethane afforded the labile ω-acetates 8 and subsequent acid catalyzed condensation with α-unsubstituted pyrrole-2-carboxylates yielded the related pyrrolylcycloalka[b]pyrroles 29 and 30. The α-unsubstituted pyrroles 14 and 23 were prepared by condensing α,β-unsubstituted ketones, or their β-acetoxycarbonyl precursors, with benzyl N-tosylglycinate in the presence of DBU, followed by dehydration with POCl3-pyridine and base catalyzed elimination of p-toluenesulfinic acid. Dipyrrole dibenzyl esters 29 and 30 were hydrogenolysed over 10% Pd-C to give the corresponding dicarboxylic acids. Acid catalyzed condensation with diformyldipyrrylmethane 33 under modified MacDonald '2 + 2' conditions afforded a series of four cycloalkanoporphyrins 4a-d with seven- or eight-membered exocyclic rings. Although the meso,β-butanoporphyrins 4a and 4b were isolated in good yields, poorer results were obtained for the related meso,β-pentanoporphyrin: 4c and 4d. It is proposed that the eight-membered carbocyclic ring distorts the geometry of the open-chain tetrapyrrolic intermediates and this deleterious influence results in the lower yields observed.
- Bastian, Jolie A.,Lash, Timothy D.
-
p. 6299 - 6310
(2007/10/03)
-
- 3-Benzyloxy-1-isocyanopropenes. Synthesis and use as 3-hydroxypropanoyl anion equivalents
-
New acyl anion equivalents bearing a hydroxyl group at the β-position have been developed. Treatment of 3-benzyloxy-1-isocyanopropenes with lithium diisopropylamide (LDA) in THF at -78°C generated the 1-lithio compounds, which reacted with alkyl halides to afford the corresponding 1-alkylated products in good yields. Acid hydrolysis of these alkylated products followed by hydrogenolysis of the resulting β-benzyloxyethyl ketones led to β-hydroxyethyl ketones.
- Kobayashi, Kazuhiro,Akamatsu, Hideki,Takada, Keiichiro,Morikawa, Osamu,Konishi, Hisatoshi
-
p. 2437 - 2440
(2007/10/03)
-
- Peroxygen compounds
-
The invention relates to novel ketone peroxides compositions containing them and processes for producing the peroxides and the compositions. The ketone peroxides are those with an alkoxy or hydroxy substituent in the α,β- or γ-position. The compositions contain (1) the peroxides and (2) water which may be in admixture with a hydrophobic or hydrophilic solvent or (3) a hydrophobic solvent. The peroxides are produced by reacting the α,β- or γ-alkoxy or hydroxy ketone with aqueous hydrogen peroxide and a source of hydrogen ions, for example a mineral acid.
- -
-
-