Day: October 13, 2022

Davis, Frankin A.; Haque, M. Serajul published the artcile< Stereochemistry of the asymmetric oxidation of ketone enolates using (camphorylsulfonyl)oxaziridines>, Related Products of 104322-63-6, the main research area is asym oxidation ketone enolate camphorylsulfonyloxaziridine; chiral hydroxy ketone preparation.

Ketones (e.g., PhCOCH2R; R = Me, Ph) were converted to their enolates with a base, e.g., (Me3Si)2NNa, and then oxidized with chiral oxaziridines, e.g., I, to give chiral hydroxy ketones, e.g. (+)(R)- and (-)(S)-PhCOCH(OH)R, in 69-95% enantiomeric excess and yields as high as 88%. Generally, sodium enolates gave the highest enantiomeric excess. A mechanism is proposed to account for the chiral recognition.

Journal of Organic Chemistry published new progress about Enols Role: RCT (Reactant), RACT (Reactant or Reagent). 104322-63-6 belongs to class isothiazole, and the molecular formula is C10H15NO3S, Related Products of 104322-63-6.

Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com

Davis, Franklin A.; Weismiller, Michael C.; Murphy, Christopher K.; Reddy, R. Thimma; Chen, Band Chi published the artcile< Chemistry of oxaziridines. 18. Synthesis and enantioselective oxidations of the [(8,8-dihalocamphoryl)sulfonyl]oxaziridines>, HPLC of Formula: 104322-63-6, the main research area is oxaziridine camphorsulfonyl chem reaction; enantioselective oxidation dihalocamphorylsulfonyloxaziridine sulfide; sulfoxide chiral; camphorylsulfonylimine halogenation chlorination bromination fluorination; halocamphorylsulfonylimine preparation halogenation epoxidation; epoxidation dihalocamphorylsulfonyloxaziridine oxone chloroperbenzoic acid; asym oxidation sulfide dihalocamphorylsulfonyloxaziridine; mol recognition oxidation sulfide dihalocamphorylsulfonyloxaziridine; steric interaction oxidation sulfide dihalocamphorylsulfonyloxaziridine; electronic effect oxidation sulfide dihalocamphorylsulfonyloxaziridine; transition state structure oxidation sulfide dihalocamphorylsulfonyloxaziridine; hydroxylation asym enolate dihalocamphorylsulfonyloxaziridine.

The synthesis and enantioselective oxidations of [(8,8-dihalocamphoryl)sulfonyl]oxaziridines I (R = F, Cl, Br) are reported. These reagents are prepared in two steps from the (camphorylsulfonyl)imine II (R1 = R2 = H) by treatment of the corresponding azaenolate with electrophilic halogen sources followed by biphasic oxidation of the resulting dihaloimine II (R1 = R2 = F; R1 = R2 = Cl; R1 = R2 = Br) with m-CPBA/K2CO3. Of these oxaziridines the dichloro reagent I (R = Cl), available on a multigram scale, affords the highest enantioselectivities for the asym. oxidation of sulfides to sulfoxides (42-74%) and for the hydroxylation of enolates (often better than 95% ee). In general the mol. recognition is predicted and explained in terms of minimization of nonbonded steric interactions in the transition states. For the asym. oxidation of sulfides to sulfoxides, secondary electronic factor related to the polarity of the sulfide and oxaziridine also play a role. Definitive evidence for chelation of the metal enolate with the C-X bond in I (R = F, Cl, Br) is not found. The mol. recognition is interpreted in terms of the higher reactivity of the reagents and an active-site structure which is sterically complementary with the enolate. For the asym. hydroxylation of the Z- and E-enolates of propiophenone, EtCOPh, the Z-enolate exhibits much higher stereoselectivity than the E-enolate: >95% vs 22% ee.

Journal of Organic Chemistry published new progress about Hydroxylation, stereoselective. 104322-63-6 belongs to class isothiazole, and the molecular formula is C10H15NO3S, HPLC of Formula: 104322-63-6.

Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com

Ma, Lifu; Dolphin, David published the artcile< Stereoselective Synthesis of New Chlorophyll a Related Antioxidants Isolated from Marine Organisms>, Category: isothiazole, the main research area is stereoselective synthesis chlorophyll a related antioxidant; chlorin stereoselective synthesis absolute configuration.

A new class of natural antioxidants, chlorophyll a related chlorins, e.g. I, II and III, have been synthesized from a chlorophyll a degradation product, pheophorbide a Me ester (IV). Claisen-type intramol. condensation of pyropheophorbide a Me ester afforded the common intermediate enol. Chlorin IV and enol I have a propensity to undergo exocyclic ring opening by ionic bases. The organic base DBU was found to be an efficient reagent for promoting the asym. hydroxylation of these chlorins, using N-sulfonyloxaziridines, without cleavage of the exocyclic rings. Model studies for hydroxylactonization have shown that periodate oxidation of hydroxy ketone stereoselectively and predominantly forms hydroxy lactone. Periodate oxidation of α-hydroxy 1,3-diketone (R) and/or (S)-II to furnish hydroxy lactone and diketone III was found out to be regioselective, and the site of reaction depends on the appropriate choice of reaction media. 1H NMR spectra have provided information on the absolute configuration of diastereomers at the C-132 or C-151 position.

Journal of Organic Chemistry published new progress about Antioxidants. 104322-63-6 belongs to class isothiazole, and the molecular formula is C10H15NO3S, Category: isothiazole.

Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com

Ma, Lifu; Dolphin, David published the artcile< Asymmetric hydroxylation of chlorophyll derivatives: a facile entry to both diastereomers of chlorophyllone a>, Synthetic Route of 104322-63-6, the main research area is asym hydroxylation chlorophyll sulfonyloxaziridine; pheophorbide asym hydroxylation sulfonyloxaziridine; pheophytin asym hydroxylation sulfonyloxaziridine.

High stereoselectivity is observed for the asym. oxidation of chlorophyll enolates derived from 132,173-pheophorbide a enol, pheophorbide a Me ester, and pheophytin a with DBU and N-sulfonyloxaziridines .

Tetrahedron: Asymmetry published new progress about Hydroxylation, stereoselective. 104322-63-6 belongs to class isothiazole, and the molecular formula is C10H15NO3S, Synthetic Route of 104322-63-6.

Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com

Davis, Franklin A.; Reddy, R. Thimma published the artcile< Asymmetric oxidation of simple selenides to selenoxides in high enantiopurity. Stereochemical aspects of the allyl selenoxide/allyl selenenate rearrangement>, Application In Synthesis of 104322-63-6, the main research area is asym oxidation selenide alkyl aryl stereochem; rearrangement allyl selenoxide selenenate; oxaziridine asym oxidation alkyl aryl selenide; selenoxide asym preparation.

For the first time simple alkyl aryl selenoxides of high enantiomeric purity (90-95% ee) and well-defined stereochem. are available via the asym. oxidation of selenides using (+)- or (-)-N-(phenylsulfonyl)-3,3-dichlorocamphoryl)oxaziridine (I). These nonracemic selenoxides, which are more stable in solution than in the solid state, exhibit high configurational stability as long as acid and moisture are excluded. Complete racemization occurs within minutes on addition of trace amounts of acid and water. The asym. oxidation of (E)- and (Z)-aryl cinnamyl selenides RSeCH:CHPh [R = Ph, 2,4,6-(Me2CH)3C6H2] with oxaziridine (+)-I affords optically active 1-phenylallyl alc. via a concerted [2,3] sigmatropic selenoxide-selenenate rearrangement. The extent of 1 → 3 chirality transfer (41-62% ee) as well as the endo/exo transition state geometry is highly dependent on the structure of the allylic selenide.

Journal of Organic Chemistry published new progress about Oxidation, stereoselective. 104322-63-6 belongs to class isothiazole, and the molecular formula is C10H15NO3S, Application In Synthesis of 104322-63-6.

Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com

Davis, Franklin; Ulatowski, Terrance G.; Haque, M. Serajul published the artcile< Asymmetric oxidation of chiral enolates in the preparation of acyclic tertiary α-hydroxy amides in high optical purity>, Application In Synthesis of 104322-63-6, the main research area is phenylpropionate enolate asym oxidation; phenylpropionamide enolate asym oxidation; hydroxy amide.

The application of double asym. induction, the asym. oxidation of chiral enolates, to the synthesis of tertiary α-hydroxy amides is described. Asym. oxidation of optically active acyclic, tetra-substituted enolate of I (R = Me) with the readily available (camphorylsulfonyl)oxaziridines (+)(2R,8aS)-II (III) or (-)(2S,8aR)-II (IV) in the presence and absence of HMPA gave tertiary α-hydroxy amide V (R = Me) in high optical purity (88-91% de). In contrast, oxidation of I (R = H) with III or IV gave V (R = H) in low yield and moderate stereoselectivities (30-50% de). The application of III and IV as ‘chiral probes’ of enolate-electrophile reaction mechanisms is discussed.

Journal of Organic Chemistry published new progress about Oxidation, stereoselective. 104322-63-6 belongs to class isothiazole, and the molecular formula is C10H15NO3S, Application In Synthesis of 104322-63-6.

Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com

Dowden, James; Moreau, Christelle; Brown, Richard S.; Berridge, Georgina; Galione, Antony; Potter, Barry V. L. published the artcile< Chemical synthesis of the second messenger nicotinic acid and adenine dinucleoside phosphate by total synthesis of nicotinamide adenine dinucleotide phosphate>, Electric Literature of 104322-63-6, the main research area is second messenger nicotinamide adenine nucleotide oligoribonucleotide preparation calcium release; nicotinic acid adenine nucleotide nicotinamide preparation calcium release NADP.

The first single-isomer synthesis of NADP is reported. Installation and maintenance of sensitive phosphate and pyridinium functionalities were key to success. Significantly, conversion of NADP into the important mammalian second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) was achieved. The biol. evaluation of the activity of the release of Ca2+ ions confirms the identity of NAADP. Ca2+ release properties against sea-urchin-egg homogenate and spectroscopic characterization are reported.

Angewandte Chemie, International Edition published new progress about Calcium release channels Role: BCP (Biochemical Process), BSU (Biological Study, Unclassified), BIOL (Biological Study), PROC (Process). 104322-63-6 belongs to class isothiazole, and the molecular formula is C10H15NO3S, Electric Literature of 104322-63-6.

Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com

Davis, Franklin A.; Clark, Charles; Kumar, Anil; Chen, Bang-Chi published the artcile< Asymmetric Synthesis of the AB Ring Segments of Daunomycin and 4-Demethoxydaunomycin>, COA of Formula: C10H15NO3S, the main research area is asym hydroxylation tetralone fragment daunomycin.

Asym. hydroxylation of the potassium enolate of β-keto ester I (R = H) with tetrahydro-9,9-dimethyl-8,8-dimethoxy-4H-4a,7-methanooxazirino[3,2-i][2,1]benzisothiazole 3,3-dioxide affords α-hydroxy β-keto ester (R)-(+)-I (R = OH) in >95% ee. The high ee’s are attributed to the fact that this enolate probably exists in one geometric form as a consequence of intramol. chelation. Reduction of the ketone in I (R = OH) with triethylsilane and conversion of the ester group into the Me ketone results in a highly efficient synthesis of the AB ring building block (R)-(-)-2-acetyl-5,8-dimethoxy-1,2,3,4-tetrahydro-2-naphthol (II, R1 = Me), a key intermediate in the asym. synthesis of the antitumor agent 4-demethoxydaunomycin. Selective deprotection of the 8-methoxy group in II (R1 = Me) with BBr3 gives II (R1 = H), important in the enantioselective synthesis of the clin. useful antitumor agent adriamycin. Attempts to prepare II more directly by asym. hydroxylation of the enolates of Me 5,8-dimethoxy-1,2,3,4-tetrahydro-2-naphthoate or the 8-benzyloxy analog of I (R = H) resulted in low ee’s, attributable to the formation of E/Z enolate mixtures and increased steric congestion in the transition state for hydroxylation.

Journal of Organic Chemistry published new progress about Hydroxylation, stereoselective. 104322-63-6 belongs to class isothiazole, and the molecular formula is C10H15NO3S, COA of Formula: C10H15NO3S.

Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com

Davis, Franklin A.; Sheppard, Aurelia C.; Chen, Bang Chi; Haque, M. Serajul published the artcile< Chemistry of oxaziridines. 14. Asymmetric oxidation of ketone enolates using enantiomerically pure (camphorylsulfonyl)oxaziridine>, Product Details of C10H15NO3S, the main research area is ketone enolate asym oxidation; oxidation stereoselective ketone enolate; asym oxidation enolate chiral oxaziridine; oxidizing agent stereoselective camphorylsulfonyloxaziridine; hydroxy ketone.

The reagent-controlled asym. oxidation of in situ generated RR1C:CR2OX (I; R = H, Me; R2 = Me, CMe3, Ph; X = Na, K, Li) by enantiomerically pure (camphorylsulfonyl)oxaziridines, e.g., (+)-II, has been investigated. The stereoselectivities for oxidation of trisubstituted enolates are good to excellent, 60-95% enantiomeric excess (ee), while those for tetrasubstituted enolates are lower; i.e., 21-30% ee. Isolated chem. yields for both types of enolate anions are good to excellent. The Na enolate anions, which could be oxidized at -78°, gave both higher yields and stereoselectivities than the corresponding Li enolates, which required warming to higher temperatures for complete oxidation The presence of HMPA generally had a deleterious effect on the stereoinduction. However, for oxidation of (E)- and (Z)-I (R = Ph, R1 = H, R2 = Me, X = Na, Li) the highest ee’s were observed in the presence of this additive. Investigation of the stereoselective trends reveals that the enolate substitution pattern and the enolate solution structure are the most important stereocontrol elements. The role that enolate geometry has in the stereoinduction is less clear, although (Z) enolates exhibit higher stereoselectivities than the (E) enolates. The results obtained in this study have been formulated into a mechanistic rational involving an SN2-type substitution of the enolate anion on II via an open transition state.

Journal of the American Chemical Society published new progress about Enolates Role: RCT (Reactant), RACT (Reactant or Reagent). 104322-63-6 belongs to class isothiazole, and the molecular formula is C10H15NO3S, Product Details of C10H15NO3S.

Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com