A general route to 3-unsubstituted 1,5-diaryl-2,4-pentanediones and -4-Methoxy-2-pentanones

2-Isoxazolines are converted to corresponding 3-hydroxyketones which are used as precursors to produce new 3-unsubstituted 1,5-diaryl-2,4-pentanediones and -4-methoxy-2-pentanones.     

Synthesis of 2R,3S,4R-dihydroxyproline from D-ribonolactone

A synthesis of 2R,3S,4R-dihydroxyproline is described in which an azide is introduced into C-2 positon of D-ribonolactone with retention of configuration.     

Synthesis of 4-ylidenebutenolides from 2-trimethylsiloxyfuran

Dehydration or dealkoxylation of the reaction products of various aldehydes, ketones, and acetals with 2-trimethylsiloxyfuran gave corresponding 4-ylidenebutenolides in good to high overall yields.     

Synthesis of (2S,4S)-4-Hydroxyproline from D-Glucose

Diacetone-D-glucose 1 gives 3- O -methylxanthate 2 on reaction with NaH/Me I. Reductive deoxygenation of compound 2 by Bu₃SnH gives the corresponding 3-deoxy glucose derivative 3 and on acid-catalyzed regioselective deprotection of C-5,6-acetonide gives the diol 4. The diol on oxidative cleavage with NaIO₄ gives the aldehyde 5, which on further condensation with benzylamine followed by reduction with NaBH₄ gives the amine 7. Z-Protection of the amine followed by methanolysis gives methyl furanoside 9. Reaction of 9 with methanesulfonyl chloride/Et₃N gives the corresponding C-3-O-mesylate derivative 10. Catalytic hydrogenation of compound 10 (Pd/C/H₂/MeOH 3 kg) gives bicyclic oxaazo compound 11, due to deprotection of the N-benzyl- and Z-protecting groups and intramolecular nucleophilic displacement of the C-2- O-mesylate by the C-5 amine in a one-pot reaction. Z-Protection of the amine 11 followed by acid-catalyzed hydrolysis gives acetal 13. Reduction of acetal by use of NaBH₄ gives Z-prolinol 14. Selective oxidation of diol 14 by (2,2,6,6-tetramethylpiperidin-1-yl)-oxyl (TEMPO)/[(bis)(acetoxy)iodo]benzene (BAIB) and NaClO₂/NaH₂PO₄, followed by Z-deprotection, gives the title compound I in 3.5% overall yield from D-glucose.     

Synthesis of O2'-methyluridine, O2'-methylcytidine, N4,O2'-dimethylcytidine and N4,N4,O2'-trimethylcytidine from a common intermediate

A facile synthesis of the title compounds from a readily accessible precursor, 3',5'-O-bis-protected O4-(2-nitrophenyl)uridine, is described.     

Synthesis of Heterocyclic Compounds from 2-Phenyl-l,2,3-Triazole-4-Formylhydrize

Many compounds containing the 1,3,4-oxadiazole and/or1,2,3(or 4)-triazole and thiadiazole ring system are reported to possess antibacterial^[1], antiinflammatory^[2], anticonrulsant^[3],CNS stimulant^[4] and pesticidal^[5] activities and excellent anthelmintic properties^[6,7]. In view of this and the results of the combined different nuclei system in a molecular always enhancing the therapeutic activities,the present work deals with the synthesis of the combined different pharmacologically active nuclei system mentioned above in a molecular through some new method.     

Synthesis of Cytotoxic 4-Sulfonyl-, 4-Sulfonylthio-and 4-Sulfothioazetidinones-2

4-Sulfonylazetidinones-2 were synthesized by the reaction of DBU and organic halides on the esters of penicillin sulfones. 4-Sulfonylthio- and 4-sulfothioazetindinones-2 were synthesized by nucleophilic substitution of the 2-benzothiazolylthio groups in 4-(benzothiazolylthio)azetidinones-2 using sodium sulfinates or sodium hydrogen sulfite. A study of their cytotoxic activities revealed the anticancer effect of compounds containing methylsulfonylthio-, 4-tolylsulfonylthio-, and 4-methoxycarbonylamino-phenylsulfonylthio-substituents at position 4 of the -lactam ring relative to a wide range of monolayer cultures of cancer cells in vitro.     

Synthesis of Asymmetric 4H-1, 3, 2-Benzodioxaphosphorin 2-Sulfides from Intramolecular Cyclization Reaction

Avarietyofbiologicalactivitiesofsome4H-l,3,2-benzodioxaphosphorin2-sulfideshavebeenreported,forexampletheinsecticideSalithionl.Thecyclicphosphonothionateshavebeenpreparedbyintermolecularcondensationofphosphorodichloridothioateswithsalicylalcoholoritsderivativesinthepresenceofabase=,andbyintramolecularcyclizationreactionofthesalicylalasthestartingmaterial3.However,theintramolecularcyclizationreactionofthe2-hydrobenzophenonesandstereochemicalstudieshavenotbeenreported.Wenowdescribeanewsynthesis…     

Synthesis of 2-imino-4-thiazolines, 2-imino-4-alkoxythiazolidines,thiazoles and 4-imidazolin-2-ones from α-halomethyl ketimines

A variety of heterocycles, including 3,4-disubstituted-2-imino-4-thiazolines, 3,4-disubstituted-4-methoxy-2-iminothiazolidines, 2,4-disubstituted-thiazoles, 2-amino-4-substituted-thiazoles and 1,5-disubstituted-4-imidazolin-2-ones, were synthesized from α-chloromethyl and α-bromomethyl ketimines by condensation with potassium thiocyanate, thiourea, ammonium thiocyanate and potassium cyanate.     

Synthesis of heierocyclic compounds from 2-phenyl-1, 2,3-triazole-4-formylhydrazine

2-Phenyl-1, 2, 3-triazole-4-formylhydrazine (2) was prepared by hydrazinolysis of the corresponding ester 1. Reaction of 2 with CS2/KOH gave the oxadiazole derivatives (3) which via, Mannich reaction with different dialkyl amines furnished 3-N, N-dialkyl derivatives (4a-c). Also, condensation of 2 with appropriate aromatic acid in POCl3 yielded oxadiazole derivatives (5a-c), or with aldehydes and ketones afforded hydrazones (6a-c). Cyclization of (6a-c) with acetic anhydride gave the desired dihydroxadiazole derivatives (7a-c). On the other hand, reaction of dithiocarbazate (8) with hydrazine hydrate gave the corresponding triazole derivative (9) which on treatment with carboxylic acids in refluxing POCl3 yielded s-triazole[3,4-b]-1, 3, 4-thiadiazole derivatives (10a-b). The structures of all the above compounds were confirmed by means of IR, 1H NMR, MS and elemental analysis.     

2,4,5-三氧-1,3,2,4-二氮二磷杂环戊烷衍生物的合成和结构

本文报道了七个新的2,4,5-三氧-1,3,2,4-二氮二磷杂环戊烷衍生物的制备, 产物的结构经IR, ^1H和^31P NMR, MS以及元素分析证实, 并利用^31P NMR和GC-MS区分了化合物的顺式和反式异构体。     

2,2,4,4—四对羟甲基酚氧基—6,6—二苯基三聚磷腈的合成

通过Friedel－Crafts反应，将本基引入到六氯环三磷腈上，然后由亲核取代反应和氢化还原反应，合成了2，2，4，4-四对羟甲基酚氧基-6，6-二苯基三聚磷腈，探索了各步的合成、分离方法，并对化合物的结构进行了表征．     

One-pot Synthesis of 4-Trifluoromethyl-l,2-dihydropyrimidines

4-Trifluoromethyl-1,2-dihydropyrimidines were synthesized in moderate yields by the one-pot reaction of 4-ethoxy-1,1,1-trifluoro-3-buten-2-one, aldehydes and ammonia catalyzed by zinc chloride under mild conditions.     

Routes To trans-Chrysanthemic Acid,IV1 Synthesis from 4-Acetyl-2-Carene

4-Acetyl-2-carene obtained from 3-carene undergoes methylation, ozonolysis, and lead tetraacetate oxidation resulting in cis-dihydrochrysanthemolactone.     

Synthesis of 2, 4, 6-trialkyl-3-hydroxypyridines

Summary A new method was proposed for the synthesis of 2,4,6-trialky1-3-hydroxypyridines by the reactions of 3,5-dialkyl-2-acylfurans with ammonia.     

Synthesis of 3, 4, 6-triaryl-2-pyrones

A preparative method was worked out for the synthesis of 3,4,6-triaryl-2-pyrones by 1,3-dipolar cycloaddition of selenium arylacylmethylides to diphenylcyclopropenone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1475–1478, November, 1977.     

(2R,4S)-4-甲基-2-哌啶甲酸乙酯的合成

以S-(-)-α-苯乙胺为原料,经一锅法制得1-(1-苄基)-6-乙氧羰基-4-甲基-3,4-二氢哌啶(3),收率58.7%。以10%Pd/C为催化剂,3经催化氢化脱苄合成了4-甲基-2-哌啶甲酸乙酯(4),收率96%;4通过减压分馏得(2R,4S)-4,含量95%,其结构经1H NMR,IR和MS确证。     

Practical Synthesis Of dl-4-hydroxybethyl-2-buten-4-olide from Furfural

dl-4-Hydroxymethyi-2-buten-4-olide(4) has been synthesized from furfural (5) through a sequence of reactions as shown in Scheme of the text.