On the synthesis and functionalisation of the 4-aza-8,12-dioxa-4,8,12,12c-tetrahydrodibenzo[cd,mn]pyrenium system

The preparative use of the reaction between tris(2,6-dimethoxyphenyl)carbenium tetrafluoroborate and excess of an arylamine such as 4-methylaniline or 4-bromoaniline to yield firstly the aryl functionalised acridinium derivatives and then further in situ reaction to yield the desired functionalised triangulenium salts was found to be problematic. A preparative route for the triangulenium salts is presented along with a demonstration of the further derivatisation by standard Suzuki coupling reaction.     

Green Route for Rapid Synthesis of 2,2′-Dithiobis(benzothiazole) by Microwave Irradiation

A green route for rapid synthesis of 2,2′-dithiobis(benzothiazole) (DM) by microwave irradiation is discussed. The reaction time was shortened to 5 min, and the yield of product was good.     

NH(4)OAc Promoted Cyclocondensation of 3-(o-Allylphenyl)pentane-1,5-diones: Synthesis of Tetracyclic Benzofused 1-Azahomoisotwistanes

A facile two-step synthetic route for preparing the novel tetracyclic skeleton of benzofused 2,6-diaryl-1-azahomoisotwistanes 2 had been developed. The route was carried out by a one-pot tandem cross-coupling reaction of o-allylbenzaldehydes 1 with aryl methyl ketones 3, and NH(4)OAc mediated the cascade cyclocondensation reaction of the resulting 1,5-diketones 4 with the 3-o-allylphenyl group in good yield in two steps.     

A concise asymmetric route to Nuphar alkaloids. A formal synthesis of (-)-deoxynupharidine

[reaction: see text] A stereocontrolled route to Nuphar alkaloids is described that employs a formal [3 + 3] cycloaddition strategy to assemble the piperidine nucleus. The addition of Pd-TMM complexes to aziridine 10 was found to be sluggish; however, the addition of a functionalized allyl Grignard reagent followed by a Mitsunobu condensation reaction provided 11 in high yield. The employment of this route in the formal synthesis of (-)-deoxynupharidine 1 is described.     

A simple,regioselective synthesis of 1,4-bis(tert-butoxycarbonylmethyl)- tetraazacyclododecane

A convenient synthetic route to 1,4-bis(tert-butoxycarbonylmethyl)tetraazacyclododecane (cyclen) (1) with high yield and excellent regioselectivity is described. Compound 1 reacted with a range of functionalized alkyl halides under two reaction conditions to give mono-N-alkylated 1,4-bis(tert-butoxycarbonylmethyl)tetraazacyclododecane (2-9) in good yield.     

Combining two-directional synthesis and tandem reactions: a short formal synthesis of halichlorine

A short and efficient synthesis of an advanced intermediate (1) in the Clive route to halichlorine has been achieved in 12 steps and 13.2% yield by a combined two-directional synthesis/tandem reaction strategy.     

A practical, enantioselective synthetic route to a key precursor to the tetracycline antibiotics

A practical, enantioselective synthetic route to a key precursor to the tetracycline antibiotics is reported. The route proceeds in nine steps (21% yield) from the commercial substance methyl 3-hydroxy-5-isoxazolecarboxylate. Key steps in the route involve enantioselective addition of divinylzinc to 3-benzyloxy-5-isoxazolecarboxaldehyde and an endo-selective intramolecular furan Diels-Alder cycloaddition reaction. The route described has provided more than 40 g of chromatographically pure 1 with 93% ee.     

合成4-巯基-1-丁醇的新方法

报道了一种合成4-巯基-1-丁醇（1）的新方法。以1,4-丁二醇为原料,经磺酰化反应及亲核取代反应制得1,总收率达75%,纯度98%（GC）,其结构经¹H NMR和MS（ESI）确证。     

Synthesis of ent-thallusin

[reaction: see text] A three-step route from sclareol oxide (6) to bromo ester 4 in 53% overall yield was achieved using the efficient oxidation of an allylic bromide to an enal with bis(2,4,6-trimethylpyridine)silver(I) hexafluorophosphate in DMSO. Stille coupling of bromo ester 4 with stannylpyridine 5 gave the trimethyl ester of ent-thallusin in 54-92% yield by the stoichiometric conversion of 4 to a vinyl palladium intermediate prior to the addition of 5 to the reaction.     

Diversity oriented synthesis of benzoxazoles and benzothiazoles

A combinatorial synthetic route yielding benzoxazoles and benzothiazoles is described. The use of o-halophenylisocyanides in the Ugi reaction (U-4CR) followed by a copper-catalyzed cyclization affords the benzoxazole as well as the benzothiazole moiety in good yield and high diversity.     

A novel route to the marasmane skeleton via a tandem rearrangement-cyclopropanation reaction. total synthesis of (+)-isovelleral

A general and efficient route to the marasmane skeleton is described. Total syntheses of two simple marasmanes (35 and 37) in racemic form were achieved using a MgI2-catalyzed rearrangement-cyclopropanation reaction of trimethylsilyl enol ether 31 derived from naphthalenone 30. The reaction proceeds in high yield with complete diastereoselectivity and does not require the use of special cyclopropanation reagents. Application of this novel route to the marasmane framework was extended to the synthesis of naturally occurring (+)-isovelleral (41).     

A Facile Route to Metal Nitride Clusterfullerenes by Using Guanidinium Salts: A Selective Organic Solid as the Nitrogen Source

Using guanidinium salts 1 and 2 as the new nitrogen sources, metal nitride clusterfullerenes (NCFs) based on a variety of metals (Dy, Sc, Y, Gd, Lu, and mixed metals Sc/Dy, Sc/Gd, Sc/Lu, and Lu/Ce) have been synthesized based on a new “selective organic solid” (SOS) route. The synthesis of Dy‐NCFs by using Dy/ 1 was studied in detail, and the optimum molar ratio of 1 /Dy/C has been determined to be 2.5:1:10. For several representative metals such as Sc, Y, Gd, Dy, and Sc/Dy, we quantitatively compared the yield of M₃N@C₈₀ synthesized by the SOS route with the reported “reactive gas atmosphere” route, thereby indicating that the yield of M₃N@C₈₀ by using 1 could be comparable to that obtained by the reactive gas atmosphere route. Three other nitrogen sources ( 3 – 5 ) were also studied for comparison, which were mixed with Dy metal but did not result in the formation of Dy‐NCF. A possible reaction scheme for the solid‐state reaction of 1 , metal, and graphite is proposed. The SOS route appears to be a general route for the synthesis of NCFs that promises both high selectivity of NCFs and high reproducibility of the fullerene yield. Another advantages of the SOS route compared to the reported “trimetallic nitride template” (TNT) process and the reactive gas atmosphere route is that no additional heating pretreatment is needed, thus simplifying the procedure and being much more facile.     

A Novel Synthesis of Diethyl Malonate

Diethyl malonate (DEM) is an important starting material in pharmaceutical and agricultural chemical industries. Traditional synthetic method by reaction mono chloroacetic acid with sodium cyanide1 is unfriendly to environment and involves complicated procedures. Therefore, green synthesis routes of diethyl malonate were investigated actively in past decade. There have been proposed various processes for preparing DEM by carbonylation of ethyl chloroacetate catalyzed by Co2(CO)82, 3. Howev…     

Practical synthesis of methyl(E)-2-(3-(3-(2-(7-chloro-2- quinolinyl)ethenyl)phenyl)-3-oxopropyl)benzoate,a key intermediate of Montelukast

A novel and practical synthetic route is presented for the preparation of methyl-(E)-2-(3-(3-(2-(7-chloro-2-quinolinyl)ethenyl) phenyl)-3-oxopropyl)benzoate,the key intermediate of Montelukast,a leukotriene antagonist.The main diarylpropane framework was prepared via a polarity conversation reaction resulting in an acyl anion equivalent followed by a nucleophilic substitution reaction.The overall yield of this approach was 61%.This method is simple for operation and suitable for industrial production.     

Regioselective and Stereoselective Synthesis of the 3-Aryl-4- phosphoryl-1, 2, 4-triazoline-5-ones

Regioselective cyclization of 1-acylthiosemicarbazides has been shown to be an excellent method for the synthesis of triazoles, thiadiazoles and oxadiazoles, with a variety of potential biological activities1-6 and utilities as pharmacological properties7…     

Synthesis of (+/-)-phloeodictine A1

The antitumor antibiotic phloeodictine A1 (2) has been synthesized by a convergent seven-step route in 8% overall yield. The key step was the Eguchi aza-Wittig reaction of 6 to give 13 followed by a retro Diels-Alder reaction to liberate 5. Addition of 11-dodecenylmagnesium bromide to 5 to give 4b, alkylation with 18b, and deprotection completed the first synthesis of 2.     

A short synthesis of 10-hydroxy 7-spirocyclopropanated camphor

[Chemical reaction: see text] A short alternative synthesis of the title 10-hydroxy 7-spirocyclopropanated camphor (4) en route to 10-hydroxycamphor (5) was achieved from cyclopentadiene-derived 4-benzyloxymethylspiro[2.4]hepta-4,6-diene (6a) by a facile regioselective Diels-Alder cycloaddition with 2-chloroacrylonitrile in an overall yield of 20%.     

Synthetic studies on the bryostatins: preparation of a truncated BC-ring intermediate by pyran annulation

[reaction: see text]. A synthesis of a potential BC-ring subunit (C9-C27) for bryostatin 1, a remarkably potent anticancer agent, has been developed in 16 steps and 18% overall yield. The key features of this route include a BITIP-catalyzed asymmetric allylation reaction, chelation-controlled allylations, a hydroformylation reaction, and a pyran annulation reaction.     

Chlorotrimethylsilane catalyzed synthesis of 1,3-diphenyl-2-propenones and their antimicrobial activities

The base- or acid-catalyzed Claisen–Schmidt condensation reaction is the common synthetic route for the synthesis of 1,3-diphenyl-2-propenone (known as chalcone). A variety of different synthetic pathways have been used over the decades in the synthesis of chalcone. Microwave irradiation in absence of solvent is employed successfully and presented here with prominent improvement over the existing methods. The reaction is incredibly accelerated in the presence of the catalyst chlorotrimethylsilane (CTMS) and found superior in terms of reaction time, product yield, safer synthetic route, and easy removal of catalyst etc. Products were characterized by elemental analysis and spectroscopy. Single crystal X-ray diffraction was used to determine crystal structures. All compounds were treated for antimicrobial activity. The profound response against bacteria and fungus pathogens by these compounds is impressive and opens up opportunities for further physiological activity studies.     

New synthesis of 4-phenyl coumarins: dalbergin and nordalbergin

A successful route to the synthesis of 4-phenylcoumarins in good yield has been developed. Vanillin on Dakin reaction yielded O-methoxyhydroquinone which on subsequent condensation with ethyl benzoyl acetate furnished dalbergin (overall yield, 65%). The latter on demethylation afforded nordalbergin (overall yield, 62%). This procedure is applicable to the synthesis of other 4-phenylcoumarins.