Synthesis of 3-carboxyalkylthia-zolidine-2-thione 4-thiosemicarbazones and their derivatives

3-Carboxyalkylthiazoltdine-2-thion-4-ones react with phosphorus pentasulfide to give 4-thiono analogs, which react with thtosemicarbazide to give the corresponding 4-thiosemicarbazones. 5-Substituted derivatives were obtained by condensation of the oxo compounds with 3-carboxyalkylthiazolidine- 2-thione-4-thiosemicarbazones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 900–902, July, 1976.     

Bond-switch rearrangement of 3-oxo-Δ4-1,2,4-thiadiazolin-5-yl ureas

5-Amino-3-oxo-Δ⁴-1,2,4-thiadiazolines 5a,b react with isocyanates to yield 1,2,4-thiadiazolidine derivatives 9a-d via bond switching of the corresponding isomers 7 . The same type of products 9e-m was obtained by treatment of 5-amino-1,2,3,4-thiatriazoles 6a-d with two equivalents of isocyanate.     

Iodo- and bromo-enolcyclization of 2-(2-propenyl)cyclohexanediones and 2-(2-propenyl)cyclohexenone derivatives using iodine in methanol and pyridinium hydrobromide perbromide in dichloromethane

alpha-Allylcyclohexane-1,3-diones undergo one-pot iodine-methanol promoted iodocyclization and oxidative aromatization to afford variously substituted 2-iodomethyltetrahydrobenzofuran-4-ones (minor) and 2-iodomethyl-4-methoxydihydrobenzofuran derivatives (major). On the other hand, the alpha-allyl-1,3-cyclohexanediones react with pyridinium hydrobromide perbromide in dichloromethane to afford mixtures of 2-bromomethyltetrahydrobenzofuran-4-ones (major) and 3-bromomethyltetrahydrobenzopyran-5-ones (minor). The prepared products and their derivatives were characterized using a combination of NMR, FT-IR and mass spectroscopic techniques.     

4-functionally substituted 3-hetarylpyrazoles: XX. Synthesis of derivatives of 5-(pyrasol-4-yl)-1,2,4-triazole and 3-(pyrazol-4-yl)-1,2,4-triazolo[3,4-c][1,4]oxazine

N-Methylimines of 3-aryl-1-phenylpyrazole-4-carbaldehyde react with ethyl 2-aryl-hydrazino-2-chloroacetate with the formation of ethyl 1-aryl-5-(pyrazole-4-yl)-4,5-dihydro-1H-1,2,4-triazolecarboxylates. Analogous reactions of pyrazol-4-carbaldehyde N-(2-hydroxy)ethylimines results in derivatives of 3-(pyrazol-4-yl)-1,2,4-triazolo[3,4-c][1,4]-oxazines.     

L-Proline-Catalyzed Knoevenagel Condensation: A Facile,Green Synthesis of (E)-Ethyl 2-Cyano-3-(1H-indol-3-yl)acrylates and (E)-3-(1H-Indol-3-yl)acrylonitriles

L-Proline has been utilized as a novel and ecofriendly catalyst in ethanol medium for the Knoevenagel condensation of indole-3-carboxyaldehydes and their N-methyl derivatives 1(a–e) and 4(a–e) with the active methylene compound, ethyl cyanoacetate (2) to afford substituted (E)-ethyl 2-cyano-3-(1H-indol-3-yl)acrylates 3(a–e) and 5(a–e) respectively. These products were reacted with dimethyl sulfate in the presence of PEG-600 as an efficient and green solvent to afford the corresponding N-mthylated derivatives 5(a–e). These Knoevenagel products react with 5% NaOH, yielding (E)-3-(1H-indol-3-yl)acrylonitriles 6(a–e) and 7(a–e).     

Potassium Fluoride Promoted Reaction of 3-Acylsubsti-Tuted 2H-1-Benzopyran-2-Ones with Acid Anhydrides. An Improved Method for the Synthesis of 4-(2-Oxoalkyl)-2H-Chroman-2-Ones. Part III1

The reaction of 3-acylsubstituted 2H-1-benzo-pyran-2-ones 1, 5 and 11a-c with acid anhydrides in the presence of potassium fluoride (KF)/molecular sieves 4A gives the 4-(2-oxoalkyl)-2-oxochromans 2, 6 and 12a-c as the main products. Also the 3-carboxylic acid derivatives, such as esters and N,N-dialkylamides, of 2H-1-benzopyran-2-one (11d-g) react with isobutyric acid anhydride in the presence of KF/molecular sieves 4A to give the corresponding 2-oxochroman-4-acetic acid derivatives.     

Studies on arylhydrazonoisoxazolinethiones. Behaviour of 4-arylhydrazono-3-phenyl-2-isoxazoline-5-thiones toward hydrazines,grignard reagents and alkylating agents

The 4-arylhydrazono-3-phenyl-2-isoxazoline-5-thiones 2 react with hydrazines to yield the 5-hydrazones 3 and 5 . The reaction of 2 with Grignard reagent resulted in addition of the reagent to the thiocarbonyl group to yield 7 . Treatment of 2 with diazomethane effected S - and N -methylation beside 1,2,3-triazole derivative 11 obtained through isomerisation. The potassium salt of 2 react with alkyl halides to yield the S-alkyl derivatives 12 .     

Electrophilic substitution of diazonium salts in 2-amino-4-(alkyl or aryl)oxazoles

Aryl diazonium fluoborates react readily with 2-amino-4-alkyloxazoles and 2-amino-4-aryloxazoles under mild conditions. The products are the corresponding 5-arylazo derivatives formed, in 44-98% yield free from side products.     

Addition reactions of 2-polyfluoroalkyl substituted 1,3-thiazolin-4-one derivatives

2-Polyfluoroalkyl-5-methoxycarbonylmethylene-thiazolin-4-ones react as dienophiles on the exo-cyclic ylidene bond to give spiro-derivatives and as 1,3-dienes with olefins to give dihydropyranothiazole derivatives. The endo-cyclic CN bond in these compounds do not enter into the cycloaddition reactions.     

Synthesis of isomeric 4- and 5-hydroxylaminothiazolidin-2-thiones

Tsomeric 4- and 5-hydroxylaminothiazolidin-2-thiones were synthesized by the reaction of 1,2-aminosubstituted oximes with CS₂, and of dimeric olefin nitrosochlorides with dithiocarbamate salts. These compounds react with aldehydes and ketones to form the respective nitrones. In contrast to the 5-derivatives, the 4-hydroxylamino derivatives hydrolyze to 4-hydorxythiazolidin-2-thiones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 549–553, April, 1986.     

Thiadiazole ring opening in the derivatives of 2-substituted 5-(1,2,3-thiadiazol-4-yl)-3-furoic acid under the action of bases

Transformations of the derivatives of 2-substituted 5-(1,2,3-thiadiazol-4-yl)-3-furoic acid under the action of bases has been studied. In the presence of potassium tert-butylate in THF, the studied compounds decompose with the cleavage of the thiadiazole ring, liberation of nitrogen, and formation of labile acetylene thiolates. In the presence of methyl iodide, these salts form stable 2-methylthioethynylfurans. Under the action of sodium ethylate in ethanol, thiadiazole ring of ethyl [2-methyl-5-(1,2,3-thiadiazol-4-yl)]-3-furoate is split to form the corresponding sodium acetylene thiolate. Under the action of ethanol, two molecules of this salt give bis(furyl)dithiafulvene. In the DMF–potassium carbonate system, acetylene thiolates react with primary and secondary amines giving thioamides of (4-ethoxycarbonyl-5-methylfur-2-yl)acetic acid. Treating of ethyl 2-methyland 2-N-morpholinomethyl-5-(1,2,3-thiadiazol-4-yl)-3-furoates with hydrazine hydrate leads to hydrazinolysis of the ester group and cleavage of thiadiazole ring resulting in the formation of hydrazides of 4-hydrazinocarbonylfur-2-ylacetic acid. In the case of ethyl 2-acetoxymethyl- and 2-(4-nitrophenoxy)methyl-5-(1,2,3-thiadiazol-4-yl)-3-furoates, thiadiazole ring is retained and exclusively hydrazinolysis of the ester groups is observed.     

Alkyl 2-(2-benzoyl-2-ethoxycarbonyl-1-ethenyl)amino-3-dimethylaminopropenoates in the synthesis of heterocyclic systems

Alkyl 2-(2-benzoyl-2-ethoxycarbonyl-1-ethenyl)amino-3-dimethylaminopropenoates 4a,b were prepared. They react with C-nucleophiles such a 2-pyridinylacetonitrile 5 and methyl-2-quinolinylacetate 8, cyclohexane-1,3-dione 10 and its derivatives 12 and 14, resorcinol derivative 16 , 2-naphtol 18, 2-pyranone derivatives 20 and 22, and 4-hydroxypyridin-2(1H)-one 24, to form substituted amino derivatives of quinolizine 6, benzo[c]quinolizine 9, tetrahydrobenzopyran-2-one 11, 13, 15 , naphto[2,1-b]pyran-3-one 19 , pyranopyranones 21, 23, and pyrano[3,2-c]pyridine 25.     

Biphilic properties of substituted triphenylphosphoranylideneacetonitriles bearing 4,5-Di(arylsulfonyl)-1,3-thiazol-2-yl fragments at the ylide center

Phosphonium ylides stabilized by nitrile and 4,5-di(arylsulfonyl)-1,3-thiazol-2-yl fragments show biphilic reactivity. They react with aromatic aldehydes upon heating revealing a noticeable activity of ylide center and are condensed with typical nucleophiles at C⁴ center of the thiazole ring with the elimination of arylsulfonyl group under mild conditions. New 1,3-thiazole derivatives were obtained whose structures were proved by chemical, spectal and X-ray structural investigations.     

Partial Dehydrogenation of Saturated 4-Phenyl-1(2H)-phthalazinone Derivatives by Thionyl Chloride

cis-4a, 5,6,7,8,8a-Hexahydro-4-phenyl-1(2H)-phthalazinones (2) react with thionyl chloride in benzene to give tetrahydro derivatives (3); the corresponding reaction of methylene bridged derivatives (5) is also described.     

[2+4]Cycloaddition of perfluoroazomethines

Conclusions Perfluoroazomethines react with cyclopentadiene at 160–180°C to form [2 + 4]-cycloadducts, viz., fluorine derivatives of 5-azabicyclo[2.2.1]hept-2-ene. These derivatives were used to obtain the products of the radical addition of chlorine, bromine, and bis(trifluoromethyl)-nitroxyl.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1437–1440, June, 1986.     

Hydrothermal synthesis method of 5-(4'-methylbiphenyl-2-yl)-1H-tetrazole

A clean and safe synthesis method of 5-(4’-methylbiphenyl-2-yl)-1H-tetrazole was found:under hydrothermal conditions,1.2 equiv.of 4’-methylbiphenyl-2-carbonitrile react with 1 equiv.of sodium azide in a mixed solvent of propane-1,2-diol/H2O,with 1.5 equiv.of ammonium chloride and 0.2 equiv.of ammonium fluoride as catalyst.After simple post-processing,the yield can be improved to 95%,and the purity of the product is 99%without further recrystallization.     

Some novel reactions of 2-amino-4-methyloxazole with aldehydes: Aryl and alkyl hydoxymethylation at C-5

2-Amino-4-methyloxazole reacts with aldehydes to give products having a hydroxymethyl function at C–5. No Schiff's bases were formed. Reactions seem to be confined to 4-alkyl substituted-2-aminooxazoles as 2-aminooxazole and its 4-phenyl and 2-acetomido derivatives fail to react with aldehydes. The nature of the aldehyde affects the amount of the product formed.     

Some Cyclization Reactions with 1,3-Diphenyl-5-Imino-2-Imidazolidinone-4-Thione

1,3-Diphenyl-5-imino-2-imidazolidinone-4-thione (II) was treated with diazomethanes to give (III-V). Interaction of (II) with amino compounds furnished the corresponding 4-substituted imino derivatives (VIa-m). Imidazoquinoxaline derivatives (VIIIb, c) were obtained through interaction of (II) with o-phenylenediamines. Condensation of (II) with hydrazines afforded the hydrazones (IX, Xa, b). Semicarbazone and thiosemicarbazone derivatives (XIIa-d) were prepared from the reaction of (IX) with isocyanates and isothiocyanates. Again (II) was allowed to react with n-butylmagnesium bromide and HgCl₂ to give (XIII) and (XIV) respectively.     

Synthesis of 5S-(1-Oxoalkyl and Aryl)-2-pyrrolidinone Derivatives1

N-Benzyl pyroglutamate esters react with aryllithium reagents and methyllithium to give moderate to good yields of 5-(1-oxoaryl) or 5-(1-oxoalkyl)-2-pyrrolidinone derivatives. The reaction proceeds without racemization, but is accompanied by formation of 5-(1-hydroxy-1-alkyl)-2-pyrrolidinone derivatives. This reaction gives very poor yields of ketone products with most other alkyl organolithium reagents such as n-butyllithium. Grignard reagents react to give primarily the alcohol.     

Synthesis of 3-(2-Phenylquinolin-4-yl)/3-(l-p-Chlorophenyl-5-methyl-1, 2,3-triazol-4-yl)-s-triazolo[3,4-b]-1, 3,4-thiadiazine Derivatives

s-Triazolo[3, 4-b]-1,3,4-thiadiazine derivatives constitute an important class of organic compounds with diverse biological activities. 2-Phenylquinoline and 1,2, 3-triazole derivatives are very attractive heterocyclic systems due to their wide use in medicine, agriculture and industry^[1]. Incorporation of 2-phenylquinoline and 1,2,3-triazole moiety into the 3-position of s-triazolo[3,4-b]-l, 3,4-thiadiazine ring system may enhance their biological activity. In light of the above findings, we synthesized some new s-triazolo[3, 4-b]-1, 3, 4-thiadiazine derivatives 2a-b~6a-b by the condensation of 4-amino-5-mercapto-3-(2-phenylquinolin-4-yl)/3-(1-p-chlorophenyl-5-methyl-1, 2,3-triazol-4-yl)-1, 2, 4-triazoles 1a-b with chloroacetalde-hyde, ω-bromo-ω-(1H-1, 2, 4-triazol-1-yl)acetophenone, chloranil, 2-bromocyclohexanone, 2, 4'-dibromoacetophenone, respectively.