Tag: M.W=300-350

Nicolaou, K. C. published the artcileSynthesis of iso-epoxy-amphidinolide N and des-epoxy-caribenolide I structures. Initial forays, Quality Control of 99438-28-5, the publication is Organic & Biomolecular Chemistry (2006), 4(11), 2119-2157, database is CAplus and MEDLINE.

Two strategies for the projected total synthesis of the phenomenally potent antitumor macrolides amphidinolide N and caribenolide I are described. The title compounds are introduced as challenging and unique targets for chem. synthesis, and their retrosynthetic anal. is presented. The synthesis of the four defined key building blocks, required for the construction of amphidinolide N, in their enantiomerically pure forms, is described, followed by the coupling through hydrazone alkylation processes to generate the complete C6-C29 carbon framework (I) of the target compound Fusion of the remaining C1-C5 sector onto the mol. by metathesis-based methods was unsuccessful, resulting in the adoption of a second-generation strategy which called for the employment of one of the array of palladium-catalyzed cross-coupling reactions to generate the C5-C6 carbon-carbon bond. Vinyl bromide II, representing the C6-C29 skeleton of caribenolide I, was prepared through the sequential alkylation, but failed to engage in the appropriate cross-coupling reaction with a variety of C1-C4 partners. Despite these setbacks, the information gleaned from these endeavors was to prove invaluable in laying the foundation for the eventual successful approach to the macrocyclic structures of amphidinolide N and caribenolide I.

Organic & Biomolecular Chemistry published new progress about 99438-28-5. 99438-28-5 belongs to ethers-buliding-blocks, auxiliary class Chiral,Aliphatic cyclic hydrocarbon, name is (+)-B-Methoxydiisopinocampheylborane, and the molecular formula is C21H37BO, Quality Control of 99438-28-5.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Vuong, Sophie published the artcileFormal synthesis of TMC-69-6H via a one-pot enantioselective domino proline-mediated aldol/olefin homologation procedure, Application of (+)-B-Methoxydiisopinocampheylborane, the publication is Tetrahedron (2012), 68(2), 433-439, database is CAplus.

Enantioselective synthesis of TMC-69-6H (I) was accomplished from readily accessible pyridone derivative (II) via a domino proline-mediated aldol reaction/olefin homologation, followed by tandem ring-closing and cross metathesis.

Tetrahedron published new progress about 99438-28-5. 99438-28-5 belongs to ethers-buliding-blocks, auxiliary class Chiral,Aliphatic cyclic hydrocarbon, name is (+)-B-Methoxydiisopinocampheylborane, and the molecular formula is C18H34N4O5S, Application of (+)-B-Methoxydiisopinocampheylborane.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Nicolaou, K. C. published the artcileSynthesis of iso-epoxy-amphidinolide N and des-epoxy-caribenolide I structures. Revised strategy and final stages, Category: ethers-buliding-blocks, the publication is Organic & Biomolecular Chemistry (2006), 4(11), 2158-2183, database is CAplus and MEDLINE.

A general and highly convergent synthetic route to the macrocyclic core structures of the antitumor agents amphidinolide N and caribenolide I has been developed, and the total synthesis of iso-epoxy-amphidinolide N and des-epoxy-caribenolide I structures is described. Central to the revised strategy was the use of a Horner-Wadsworth-Emmons olefination between a β-ketophosphonate and an aldehyde to construct the C1-C13 sector common to both amphidinolide N and caribenolide I. Stereoselective alkylation allowed for the rapid assembly of the complete caribenolide I carbon skeleton. Key steps in the completion of the synthesis of des-epoxy-caribenolide I structure I included hydrolysis of a sensitive Me ester using Me₃SnOH, followed by regioselective macrolactonization of the resulting diol seco-acid and global deprotection. An analogous sequence of late-stage manoeuvres was used to arrive at the fully deprotected des-epoxy-amphidinolide N framework, obtained as a mixture of hemiacetal II and its bicyclic acetal. Regio- and diastereoselective epoxidation of the C6 methylene group in the bicyclic acetal provided access to iso-epoxy-amphidinolide N stereoisomer. Several of the prepared compounds were tested for cytotoxicity against human tumor cell lines, and none showed activity.

Organic & Biomolecular Chemistry published new progress about 99438-28-5. 99438-28-5 belongs to ethers-buliding-blocks, auxiliary class Chiral,Aliphatic cyclic hydrocarbon, name is (+)-B-Methoxydiisopinocampheylborane, and the molecular formula is C21H37BO, Category: ethers-buliding-blocks.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Canova, Sophie published the artcileRearrangement of Homoallylic Alcohols Induced by DAST, Recommanded Product: (+)-B-Methoxydiisopinocampheylborane, the publication is Organic Letters (2006), 8(10), 2091-2094, database is CAplus and MEDLINE.

Nonracemic α-substituted-β-methoxy homoallylic alcs. RCH(OH)CH(OMe)CH:CH₂ [R = TBDPSOCH₂CH₂, PhCH₂OCH₂CH₂, (R)-TBDPSOCH₂CHMe, (S)-TBDPSOCH₂CHMeCH₂; TBDPS = Me₃CSi(Ph)₂; (I)] undergo diethylaminosulfur trifluoride (DAST)-mediated fluorination and rearrangement on silica gel to provide β,γ-unsaturated aldehydes RCH(CHO)CH:CH₂ [R = TBDPSOCH₂CH₂, PhCH₂OCH₂CH₂, (R)-TBDPSOCH₂CHMe, (S)-TBDPSOCH₂CHMeCH₂; (II)] in 76-90% yields and with good transfer of chirality. II are unstable to prolonged treatment with silica gel, rearranging to the corresponding α,β-unsaturated aldehydes, and are reduced with sodium borohydride to the primary homoallylic alcs. RCH(CH₂OH)CH:CH₂ [R = TBDPSOCH₂CH₂, PhCH₂OCH₂CH₂, (R)-TBDPSOCH₂CHMe, (S)-TBDPSOCH₂CHMeCH₂]. The racemic homoallylic alcs. PhCH₂CH(OH)CH₂CH:CH₂ and TBDPSOCH₂CH₂CH(OH)CH₂CH:CH₂ lacking an α-methoxy substituent undergo fluorination without rearrangement; reaction of the secondary alc. derived from I [R = (R)-TBDPSOCH₂CHMe] by hydrogenation of the olefin with DAST yields a complex mixture

Organic Letters published new progress about 99438-28-5. 99438-28-5 belongs to ethers-buliding-blocks, auxiliary class Chiral,Aliphatic cyclic hydrocarbon, name is (+)-B-Methoxydiisopinocampheylborane, and the molecular formula is C21H37BO, Recommanded Product: (+)-B-Methoxydiisopinocampheylborane.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Barrett, Anthony G. M. published the artcileApplications of Crotonyldiisopinocampheylboranes in Synthesis: Total Synthesis of Restrictinol, Name: (+)-B-Methoxydiisopinocampheylborane, the publication is Journal of Organic Chemistry (1999), 64(1), 162-171, database is CAplus and MEDLINE.

The total synthesis of restrictinol, the hydrolysis product of the antifungal natural product restricticin, starting from com. available Me (S)-(+)-3-hydroxy-2-methylpropionate was achieved. Key steps in the strategy involved (1) the use of Brown’s allylboration chem. to construct an acyclic intermediate bearing three of the four stereogenic centers of the natural product, (2) formation of a C-glycosidic vinyl iodide, and (3) introduction of the triene side chain via a Suzuki coupling reaction.

Journal of Organic Chemistry published new progress about 99438-28-5. 99438-28-5 belongs to ethers-buliding-blocks, auxiliary class Chiral,Aliphatic cyclic hydrocarbon, name is (+)-B-Methoxydiisopinocampheylborane, and the molecular formula is C21H37BO, Name: (+)-B-Methoxydiisopinocampheylborane.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Brown, Herbert C. published the artcileChiral synthesis via organoboranes. 7. Diastereoselective and enantioselective synthesis of erythro- and threo-β-methylhomoallyl alcohols via enantiomeric (Z)- and (E)-crotylboranes, Name: (+)-B-Methoxydiisopinocampheylborane, the publication is Journal of the American Chemical Society (1986), 108(19), 5919-23, database is CAplus and MEDLINE.

Isomerically pure (Z)- and (E)-crotylpotassiums were prepared by metalation of (Z)- and (E)-2-butene using a modified Schlosser procedure. The enantiomerically pure (Z)-crotyldiisopinocampheylboranes I and II were prepared by employing methoxydiisopinocampheylboranes, prepared from either (+)- or (-)-α-pinene, resp., and (Z)-crotylpotassium I and II retain their stereochem. identity under the reaction conditions and were condensed with RCHO (R = Me, Et, H₂C:CH, Ph) regioselectively and stereoselectively to yield the corresponding erythro-β-methylhomoallyl alcs. e.g., III, in ≥99% diastereoselectivities and ≥95% enantioselectivities. Similarly, the enantiomeric (E)-crotyldiisopinocampheylboranes were prepared and add to RCHO to yield the corresponding threo-β-methylhomoallyl alcs. with similar selectivities. Further, (Z)- and (E)-crotyldiisocaranylboranes IV were prepared and condensed with EtCHO to furnish the erythro– and threo-β-methylhomoallyl alcs., resp., in ≥99% diastereoselectivities and improved enantioselectivities (97%).

Journal of the American Chemical Society published new progress about 99438-28-5. 99438-28-5 belongs to ethers-buliding-blocks, auxiliary class Chiral,Aliphatic cyclic hydrocarbon, name is (+)-B-Methoxydiisopinocampheylborane, and the molecular formula is C21H37BO, Name: (+)-B-Methoxydiisopinocampheylborane.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Brown, Herbert C. published the artcileEnantiomeric Z- and E-crotyldiisopinocampheylboranes. Synthesis in high optical purity of all four possible stereoisomers of β-methylhomoallyl alcohols, Recommanded Product: (+)-B-Methoxydiisopinocampheylborane, the publication is Journal of the American Chemical Society (1986), 108(2), 293-4, database is CAplus.

Enantiomerically pure Z-crotyldiisopinocampheylboranes are prepared from B-methoxydiisopinocampheylboranes and the allylic organopotassium compound from cis-2-butene. These enantiomeric Z-crotylboranes add to AcH regioselectively and stereoselectively to give erythro-(+)- and -(-)-3-methyl-4-penten-2-ols in ≥99% diastereoselectivities and ≥95% enantioselectivities. Similarly, enantiomeric E-crotyldiisopinocampheylboranes are prepared and add to AcH to give threo-(+)- and -(-)-3-methyl-4-penten-2-ols in ≥99% diastereoselectivities and ≥95% enantioselectivities.

Journal of the American Chemical Society published new progress about 99438-28-5. 99438-28-5 belongs to ethers-buliding-blocks, auxiliary class Chiral,Aliphatic cyclic hydrocarbon, name is (+)-B-Methoxydiisopinocampheylborane, and the molecular formula is C21H37BO, Recommanded Product: (+)-B-Methoxydiisopinocampheylborane.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Hanessian, Stephen published the artcileAlternative and Expedient Asymmetric Syntheses of L-(+)-Noviose, Synthetic Route of 99438-28-5, the publication is Organic Letters (2008), 10(2), 261-264, database is CAplus and MEDLINE.

L-(+)-Noviose I, the sugar component of the antibiotic novobiocin, was synthesized from either 2,2-dimethyl-1,3-cyclopentadione or benzyl glyoxylate relying on stoichiometric and asym. processes by two independent methods, comprising six and nine steps, in 27 and 20% overall yields, resp. An unsaturated lactone II was prepared via stereoselective boron-catalyzed reduction, scandium-catalyzed Baeyer-Villiger oxidation and Saegusa oxidation from 2,2-dimethyl-1,3-cyclopentadione. II could also be prepared via stereoselective Brown allylation, ruthenium-catalyzed isomerization and ring-closing metathesis, and allylic oxidation from benzyl glyoxylate. II was then transformed to I via stereoselective reduction and dihydroxylation.

Organic Letters published new progress about 99438-28-5. 99438-28-5 belongs to ethers-buliding-blocks, auxiliary class Chiral,Aliphatic cyclic hydrocarbon, name is (+)-B-Methoxydiisopinocampheylborane, and the molecular formula is C21H37BO, Synthetic Route of 99438-28-5.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Lemarchand, Aude published the artcileSynthesis of chiral ansa-bridged macrocyclic lactams ([16]metacyclophanes) related to geldanamycin, Computed Properties of 99438-28-5, the publication is Synthesis (2005), 1977-1990, database is CAplus.

Two chiral ansa-bridged lactams ([16]metacyclophanes) I (X = CH₂, O) were synthesized starting from 2-methoxyhydroquinone diisopropyl ether in 14 (I, X = CH₂, 3.9% overall) and 16 synthetic steps (I X = O, 0.6% overall). Both compounds contain typical features of geldanamycin in the C-1 to C-9 part of the ansa chain, i.e. the α,β,γ,δ-unsaturated anilide (C-1 to C-5), the carbamate at the stereogenic carbon atom C-7 and the E-double bond between C-8 and C-9. While the rest of the ansa chain (C-10 to C-15) was an alkyl chain in compound I (X = CH₂), a more polar CH₂OCH₂CH₂OCH₂ chain was installed in compound I (X = O). Key step of the sequence was a ring-closing metathesis in which the ansa compounds were formed as a mixture of isomers. Deprotection and oxidation to the quinone failed for diisopropyl ether I (X = O) but was successfully conducted with precursor I (X = CH₂).

Synthesis published new progress about 99438-28-5. 99438-28-5 belongs to ethers-buliding-blocks, auxiliary class Chiral,Aliphatic cyclic hydrocarbon, name is (+)-B-Methoxydiisopinocampheylborane, and the molecular formula is C21H37BO, Computed Properties of 99438-28-5.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Vincent, Andrea published the artcileIdentification of candidate drugs for the treatment of ALS, Related Products of ethers-buliding-blocks, the publication is Amyotrophic Lateral Sclerosis and Other Motor Neuron Disorders (2005), 6(1), 29-36, database is CAplus and MEDLINE.

A consortium of investigators interested in neurodegenerative diseases collaborated to screen 1040 drugs in multiple neurodegenerative disease assays. One model of amyotrophic lateral sclerosis (ALS) pathogenesis in particular incorporated glutamate exposure in enriched primary rat motor neuron cultures. In this model 78 compounds decreased motor neuron death caused by 100 μM glutamate. Almost all these pharmacol. agents act at one or more of the following cellular targets: (1) protein synthesis inhibition; (2) Cox inhibition; (3) regulation of anion flux; (4) modulation of GABA receptors; (5) antioxidant, and (6) cell cycle inhibition. The most prevalent mode of action was the regulation of intracellular calcium. These data extend the understanding of motor neuron degeneration and identify a number of cellular targets for the improvement of combined therapies for neurodegenerative disease.

Amyotrophic Lateral Sclerosis and Other Motor Neuron Disorders published new progress about 637-58-1. 637-58-1 belongs to ethers-buliding-blocks, auxiliary class Inhibitor, name is 4-(3-(4-Butoxyphenoxy)propyl)morpholine hydrochloride, and the molecular formula is C42H63O3P, Related Products of ethers-buliding-blocks.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem