Convenient Total Synthesis Research Articles

Convenient total synthesis of Bistratamides H and J

Scalable total syntheses of Bistratamides H and J with remarkable yields of 22.9 % and 24.2 % over 9 steps, respectively, have been accomplished. The key step features a PPh3-promoted cascade reaction (disulfide cleavage/thiocarbonylation/intramolecular Staudinger-aza-Wittig reaction/dehydrogenation) to construct the key Boc-l-Val-thiazole fragment, DAST-promoted oxazoline synthesis, and a PyBOP-assisted macrolactamization.

Development of Convergent Hybrid Phase Ligation for Efficient and Convenient Total Synthesis of Proteins.

Simple and efficient total synthesis of homogeneous and chemically modified protein samples remains a significant challenge. Here, we report development of a convergent hybrid phase native chemical ligation (CHP-NCL) strategy for facile preparation of proteins. In this strategy, proteins are split into ~100-residue blocks, and each block is assembled on solid support from synthetically accessible peptide fragments before ligated together into full-length protein in solution. With the new method, we increase the yield of CENP-A synthesis by 2.5-fold compared to the previous hybrid phase ligation approach. We further extend the new strategy to the total chemical synthesis of 212-residue linker histone H1.2 in unmodified, phosphorylated, and citrullinated forms, each from eight peptide segments with only one single purification. We demonstrate that fully synthetic H1.2 replicates the binding interactions of linker histones to intact mononucleosomes, as a proxy for the essential function of linker histones in the formation and regulation of higher order chromatin structure.

A Ruthenium-Catalyzed C–H Activation Strategy as an Efficient Shortcut in the Total Synthesis of 6,8-Dimethoxy-1,3-dimethyl­isoquinoline

A short and convenient total synthesis of 6,8-dimethoxy-1,3-dimethylisoquinoline, employing a C–H activation/alkenylation strategy, is reported. The approach involves the CeCl3·7H2O-promoted methoximation of 2,4-dimethoxyacetophenone and a methoxime-directed ruthenium-catalyzed allylation. This was followed by a one-pot, ruthenium-catalyzed allyl to propenyl isomerization and a microwave-assisted 6π-azaelectrocylization to complete the sequence. This approach, which entails a shortcut in the synthetic management of the three-carbon side chain, is an improved and more efficient route toward the natural product, which facilitated its access in just three steps and 27.3% overall yield.

Design, Synthesis, and Biological Evaluation of the Sex Pheromone of the Asian Corn Borer, Ostrinia furnacalis (Guenée)

A convenient total synthesis of (Z)-12-tetradecenyl acetate (1a) and (E)-12-tetradecenyl acetate (1b), which are the sex pheromones of Ostrinia furnacalis (Guenée), has been achieved. The target mixture molecules, of a cis-to-trans-isomer ratio of 27 to 73, were synthesized in 40% overall yield and through [13C + 1C] synthetic strategy in five steps from commercially available and cheap industrial brassylic acid as key starting material. The electroantennogram (EAG) responses of synthetic sex pheromone to ACB male moths were conducted. The results showed that the target mixture molecules were found to have a good activity and displayed significantly stronger EAG responses ranging from 10 to 1000 μg, and the optimized stimulating dosage of the activity of synthetic sex pheromone to ACB males is 10 μg. Compared with the existing routes, this synthetic approach is operationally simple, good-yielding, and cost-effective, which could serve as a basis for developing the techniques of sex pheromone mass trapping or mating disruption and providing an environmentally benign method to control ACB pests.

Efficient and convenient total synthesis of mycothiol on a large scale

Mycothiol（MSH）是放线菌体内普遍存在的一种重要的低分子量硫醇。因此，对其进行化学合成供酶学以及抑制剂筛选所需越显重要，但其化学合成路线供放大合成的发展一直面临一些屏障。我们在文献调研的基础上，通过整合目前最便捷、高效构建糖基供体、糖基受体以及半胱氨酸侧链三个片段的策略以及二糖与侧链的连接方法，发展了一种便捷、高效、可实现放大合成MSH的全合成策略。

Pd-Catalyzed C–H Lactonization for Expedient Synthesis of Biaryl Lactones and Total Synthesis of Cannabinol

A practical Pd(II)/Pd(IV)-catalyzed carboxyl-directed C-H activation/C-O cyclization to construct biaryl lactones has been developed. The synthetic utility of this new reaction was demonstrated in an atom-economical and operationally convenient total synthesis of the natural product cannabinol from commercially available starting materials, with the newly developed method used for two key steps.

A new route for total synthesis of (±) dephospho Form B of molybdenum cofactor by direct one step thiophene annulation from suitable pterin alkynes

A new convenient total synthesis of (±) dephospho Form B of molybdenum cofactor has been described. The development of direct thiophene annulation onto pterin from a simple direct thiophene annulation at the alkyne moiety at 6-position of pterin is successfully achieved by using excess of sodium sulfide. This novel method conveniently led to the synthesis of a series of pterin fused α-substituted thiophenes (9–11, respectively).

Convenient total synthesis of taranabant (MK-0364), a novel cannabinoid-1 receptor inverse agonist as an anti-obesity agent

Being obese has various health problems that are related to type 2 diabetes mellitus, cardiovascular disease, hypertension, hyperlipidemia, and fibrinolytic abnormalities. Merck's taranabant (MK-0364), a CB1R inverse agonist, is currently in Phase 3 clinical trials, and is being actively pursued by Merck toward obesity market. Merck intends to file for FDA approval of taranabant in 2008. In order to overcome practical difficulty involved in lab-scale preparation of taranabant with a dynamic kinetic resolution procedure developed by Merck's process group, we developed a ‘user-friendly’ method to install stereogenic centers by adopting Evans asymmetry chemistry. This method allowed us to prepare readily sub-gram scale of the target compound in a convenient way.

A Convenient Total Synthesis of (+)‐Decursinol from Resorcinol.

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A Convenient Total Synthesis of (+)-Decursinol from Resorcinol

A method for preparation of (+)-decursinol from resorcinol is provided to simplify the preparation steps, improve preparation yield and reduce the preparation costs by arranging condensation-cyclization reaction at the early time of the reaction, so that the condensation-cyclization reaction does not influence the chiral reaction requiring expensive reagents. A method for preparation of (+)-decursinol represented by the formula(6) comprises the steps of: performing condensation-cyclization reaction with resorcinol represented by the formula(1) and 2-methyl-3-butene-2-ol to prepare 7-hydroxy-2,2-dimethylchroman represented by the formula(2); performing condensation-cyclization reaction with the compound represented by the formula(2) and ethyl propiolate to prepare 8,8-dimethyl-7,8-dihydro-6H-pyrano9[3,2-g] chromen-2-one represented by the formula(3); oxidation-reacting the compound represented by the formula(3) with DDQ(dichloro dicyano quinone) to prepare xanthyletin represented by the formula(4); epoxylating the compound represented by the formula(4) with Jacobsen's (S,S)-salen-Mn(III) catalyst to prepare (6S, 7R)-6,7-epoxy-8,8-dimethyl-7,8-dihydro-6H-pyrano[3,2-g]chromen-2-one represented by the formula(5); and reduction-reacting the compound represented by the formula(5) with NaBH3CN.

Study on Tonghaosu and Its Analogs: Isolation, Structure Identification and Synthesis of Antifeedant B‐ring‐homo‐tonghaosu

AbstractThe methanolic extract from a Chinese endemic Chrysanthemum plant, Dendranthema indicum var. aromaticum, was found to show high antifeeding activity against Pieris brassicae L., and by bioassay‐guided separation, the active component, B‐ring‐homo‐tonghaosu, 2–(2′.4′‐hexadiynylidene)‐1, 6‐dioxaspiro‐[4, 5]dec‐3‐ene (2) was isolated. Its structure was elucidated by comparing its spectroscopic data with those of 2 reported in the literatures. Furthermore new convenient total synthesis methods of B‐ring‐homo‐tonghaosu were also developed to confirm its structure and make its further application in crop protection available. In addition, extensive comparison of spectroscopic data showed that the structure of compound 21 reported in literature should be revised to 2.

Convenient Total Synthesis of NM‐3, an Antiangiogenesis Agent, and Its Optical Resolution.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Convergent and Convenient Total Synthesis of Phytoalexin‐Elicitor Active Heptasaccharide by One‐Pot Sequential Glycosylation.

Convergent and convenient total synthesis of branched hepta-β-glucoside 1 having phytoalexin-elicitor activity was efficiently accomplished by way of two one-pot sequential glycosylation reactions. Trisaccharide 8 was synthesized in high yield by TfOH-catalyzed one-pot glycosylation using three component monosaccharides and subsequent selective deprotection of a 6′-O-TBDPS group. The second one-pot glycosylation of trisaccharide 8 with the three monosaccharides smoothly proceeded to afford heptaglucoside 11 stereoselectively in 48% total yield based on monosaccharide 3. The targeted compound 1 was obtained in high yield after the removal of the protecting groups.

Convergent and Convenient Total Synthesis of Phytoalexin-Elicitor Active Heptasaccharide by One-Pot Sequential Glycosylation

Abstract Convergent and convenient total synthesis of branched hepta-β-glucoside 1 having phytoalexin-elicitor activity was efficiently accomplished by way of two one-pot sequential glycosylation reactions. Trisaccharide 8 was synthesized in high yield by TfOH-catalyzed one-pot glycosylation using three component monosaccharides and subsequent selective deprotection of a 6′-O-TBDPS group. The second one-pot glycosylation of trisaccharide 8 with the three monosaccharides smoothly proceeded to afford heptaglucoside 11 stereoselectively in 48% total yield based on monosaccharide 3. The targeted compound 1 was obtained in high yield after the removal of the protecting groups.

Total synthesis of chromomoric acid B and F methyl esters

A convenient total synthesis of chromomoric acid B methyl ester 1 and the first synthesis of chromomoric acid F methyl ester 2 have been described. A one-pot Michael addition-enolate trapping sequence afforded ketone 5 which after a few steps was converted to 1. Retro Diels-Alder reaction of ester 7 afforded enone 9 which was then transformed to the target molecule 2 through hydrogenation and α-hydroxylation.

Convenient total synthesis of a 4-helix template-assembled synthetic protein (TASP) molecule by chemoselective ligation

The chemoselective ligation approach to the preparation of complex peptides has been used in a simple, convenient synthesis of a template-assembled synthetic protein (TASP) molecule. Reaction of a readily prepared synthetic pro-helical peptide-αCOSH, in unprotected form, with a synthetic (BrAc) 4 template molecule, also in unprotected form, proceeded rapidly in aqueous solution to give a uniform product in high yield. The resulting 4-helix TASP was simply purified to homogeneity, and the covalent structure was defined by ion-spray mass spectrometry [obs MW 6647.1±2.8 D; calc 6645.6 (monoisotopic), 6649.9 (average isotope composition)]. The conformation of the resulting macromolecule was determined by circular dichroism (CD) and was highly helical

Total Synthesis of (±) Thaicanine

Abstract A convenient total synthesis of (±) thaicanine (5) is described from 2-benzyloxy-3,4-dimethoxyphenylethylamine (1).

ChemInform Abstract: A Convenient Total Synthesis of (.+‐.)‐Isoochracinic Acid (VI), a Phthalide from Alternaria kikuchiana.

ChemInformVolume 18, Issue 5 Natural Products ChemInform Abstract: A Convenient Total Synthesis of (.+-.)-Isoochracinic Acid (VI), a Phthalide from Alternaria kikuchiana. S. N. YEOLA, S. N. YEOLA Dep. Chem., Univ. Poona, Pune 411 007Search for more papers by this authorR. S. MALI, R. S. MALI Dep. Chem., Univ. Poona, Pune 411 007Search for more papers by this author S. N. YEOLA, S. N. YEOLA Dep. Chem., Univ. Poona, Pune 411 007Search for more papers by this authorR. S. MALI, R. S. MALI Dep. Chem., Univ. Poona, Pune 411 007Search for more papers by this author First published: February 3, 1987 https://doi.org/10.1002/chin.198705309Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume18, Issue5February 3, 1987 RelatedInformation

1,6-Dihydro-3(2H)-pyridinones as synthetic intermediates. A convenient total synthesis of (.+-.)-cleavamine.

A novel and convenient total synthesis of (±)-cleavamine (1) starting from ethyl 1, 6-dihydro-3 (2H)-pyridinone-1-carboxylate (2) is described.