Facile synthesis of pyrrolo[2,1‐c][1,4]benzodiazepine‐5,11‐dione dimer

Efficient synthesis of biological important pyrrolo[2,1‐c][1,4]benzodiazepine‐5,11‐dione dimer linked through the C‐2 positions by fumarate group is described.     

Synthesis of 1,3‐thiazole and 1,2,4‐oxadiazole substituted spiro[3H‐indole‐3,2′‐thiazolidine]‐2,4′(1H)‐diones

Some new derivatives of spiro[3H‐indole‐3,2′‐thiazolidine]‐2,4′(1H)‐dione with the heterocyclic ring such as substituted thiazole and 1,2,4‐oxadiazole attached to the indolinone ring via CH₂ linkage has been synthesized in moderate yields. The synthesis have been carried out by making use of the reactivity of the NH group of the indolinone moiety present in spiro[3H‐indole‐3,2′‐thiazolidine]‐2,4′(1H)‐dione.     

An efficient one‐pot synthesis of n‐carboxymethylacridine‐1,8‐dione derivatives under microwave irradiation

A series of N‐carboxymethylacridine‐1,8‐dione derivatives were synthesized by one‐pot reaction of aldehyde, dimedone and glycine in glycol under microwave irradiation without catalyst with excellent yields (78‐92%) and short reaction time (4‐8min). And the reaction was not only suitable for aromatic monoaldehyde, but also aromatic dialdehyde.     

On the synthesis of 5‐ethyl meldrum's acid

Reductive alkylation of Meldrum's acid with acetaldehyde can give, depending on the experimental conditions, either a new dimer (5‐[3‐(2,2‐dimethyl‐4,6‐dioxo‐1,3‐dioxan‐5‐yl)butyl]‐2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione) or ethyl Meldrum's acid (2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione). A best way to obtain this latter product is synthesis of 1‐ethoxyethylidene Meldrum's acid from reaction of Meldrum's acid with triethyl orthoacetate, followed by a sodium borohydride reduction.     

Facile three‐component one‐pot synthesis of indeno‐[1,2‐b]quinolin‐9,11(6H,10H)‐dione derivatives

One‐pot three‐component cyclocondensation of aldehydes, 1,3‐indanedione and enaminones proceeds in the presence of acetic acid to afford Indeno[1,2‐b]quinolin‐9,11(6H,10H)‐dione derivatives, The method has the advantage of excellent yields(85‐94%) and simple workup procedure.     

A general synthesis of 8‐hydroxy‐6‐substituted‐1,7‐naphthyridines

A general method for the synthesis of 8‐hydroxy‐6‐substituted‐1,7‐naphthyridines is described using acylation of the dianion derived from tert‐butylamide 1 , followed by cyclization of the resulting intermediate ketones 2 with ammonium acetate.     

Reactivity of 3‐amino‐3H‐quinazolin‐4‐one derivatives towards some electrophilic and nucleophilic reagents and using of the products in the building of some interesting heterocycles as anticancer agent

The chemical reactivity of N‐[1‐(3‐amino‐6,8‐dibromo‐4‐oxo‐3,4‐dihydro‐quinazolin‐2‐yl)‐2‐(2‐chlorophenyl)‐vinyl]benzamide ( 3 ) towards electrophilic and nucleophilic reagents have been reported. Structures of the products 3‐24 have been confirmed by elemental analysis and spectral data (IR, ¹H‐NMR, ¹³C and MS). The bioassay indicates that some of the prepared compounds have a good selective anticancer activity.     

Structure determination of N‐methyl‐tetrahydro‐5H‐indazol‐5‐ones

This paper communicates the (regio) synthesis and a convenient NMR structural assignment method for N‐methyl‐tetrahydro‐5H‐indazol‐5‐one isomers. The cyclization reaction of 7‐(hydroxymethylene)‐1,4‐dioxaspiro[4,5]decan‐8‐one ( 3 ) with methylhydrazine yields, after de‐protection predominately the N‐2 methyl isomer 2 . Analysis of the product ratio and structural assignments are based on NMR data including NOE difference experiments and subsequently confirmed with X‐ray crystallography. These findings are in sharp contrast with the literature. The experimental conditions used to optimize the synthesis of the individual isomers are discussed.     

Some nucleophilic substitutions in 2‐cyano‐3‐nitroimidazo[1,2‐a]pyridine

In some nucleophilic substitution reactions of 2‐cyano‐3‐nitroimidazo[1,2‐a]pyridine, nitrogen (alkylamines, guanidine) and oxygen nucleophiles (alkoxides) underwent substitution of the 2‐cyano group, while sulfur nucleophiles (alkylthiols) underwent substitution of the 3‐nitro group.     

Synthesis and characterization of 4‐aryl‐5‐(1‐aryl‐2‐methyl‐2‐nitropropyl)‐1,2,3‐selenadiazoles

The synthesis of a new set of selenadiazoles, 4‐aryl‐5‐(1‐aryl‐2‐methyl‐2‐nitropropyl)‐1,2,3‐selenadiazoles ( 4 ) derived from 2‐[4‐methyl‐4‐nitro‐1,3‐diarylpentylidene]‐1‐hydrazinecarboxamide ( 3 ) has been reported. THF has been found to be the solvent of choice for this reaction. Structural features of 3 and 4 have been analyzed by NMR and X‐ray techniques.     

Synthesis of some new spiro naphtho[2,3‐d][1,3]dithiole‐4,9‐dione derivatives

2(1‐Acetyl‐2‐oxopropylidene)naphtho[2,3‐d][1,3]dithiole‐4,9‐dione 1 reacts with a variety of bidentates reagents to give some new functionally substituted spiro naphthodithiole‐4,9‐dione derivatives.     

An efficient one‐pot synthesis of 5‐aryl substituted 2‐amino‐5,8‐dihydropyrido[2,3‐D] pyrimidin‐4,7‐diones under microwave irradiationl without catalyst

A series of 5‐aryl substituted 2‐amino‐5,8‐dihydropyrido[2,3‐d]pyrimidin‐4,7‐diones were synthesized through one‐pot condensation of 2,6‐diaminopyrimidin‐4‐one, aldehyde and Meldrum's acid using glycol as energy transfer agent under microwave irradiation without catalyst. The one‐pot protocol in the absence of catalyst has the advantage of good yield (86‐95%), short route and reaction time (3‐6 min) and environmentally friendly.     

Synthesis and tautomerization of 6,7‐dihydro‐(1,2,3)‐triazolo[1,5‐a]pyrimidines

The condensation of 5‐amino‐4‐phenyl‐1,2,3‐triazole ( 1 ) with chalcones 2a‐e or 3‐dimethylamino‐propiophenone ( 4f ) leads to the 6,7‐dihydro‐(1,2,3)‐triazolo[1,5‐a]pyrimidines 3a‐f. The equilibrium of 3 and the tautomeric 4,7‐dihydro‐(1,2,3)‐triazolo[1,5‐a]pyrimidines 3′ is described.     

Synthesis,structure and biological activities of [α‐(alkylcarbonyl)‐2‐(1,2,4‐triazol‐1‐yl)]ethyl‐N,N‐dialkydithiocarbamate derivatives

Seven 1,2,4‐triazole compounds containing the N,N‐dialkyldithiocarbamate group were designed and synthesized. Their structures were identified using infrared spectroscopy, element analysis, ¹H NMR spectroscopy and mass spectrometry, and in two cases by single crystal X‐ray diffraction. The result of the biological test showed that the seven compounds all have fungicidal and plant growth‐regulating activities.     

Formation of pyridazino[4,5‐c]pyridazine derivatives upon [4+2]cycloaddition of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione to cross‐conjugated monoferrocenyltrienes

Cross‐conjugated monoferrocenyltrienes react with 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione to give mono‐ and bis‐[4+2]‐cycloaddition products. Nonsubstituted and 2,4‐disubstituted 3‐ferrocenylmethylidenepenta‐1,4‐dienes afford respective pyridazine and pyridazino[4,5‐c]pyridazine derivatives. Their structures were established based on ¹H and ¹³C NMR data and X‐ray diffraction analysis.     

Synthesis of new spiro‐[isothiochromene‐3,5′‐isoxazolidin]‐4(1H)‐ones

A series of seven new 2′,3′,4′‐substituted spiro[isothiochromene‐3,5′‐isoxazolidin]‐4(1H)‐ones ( 7‐13 ) has been prepared in the reaction of benzylidene(phenyl)azane oxide ( 5 ) or benzylidene(methyl)azane oxide ( 6 ) with (3Z)‐3‐(4‐substituted‐benzylidene)‐1H‐isothio‐ chromen‐4(3H)‐one ( 1‐4 ). The reaction occurs by a 1,3‐dipolar cycloaddition mechanism that leads to the regiospecific formation of various spiroisoxazolidines ( 7‐13 ).     

New access to thiazolo[4,5‐d]pyrimidine derivativess

4‐Amino‐5‐bromo‐2‐substituted‐aminopyrimidines are readily obtained from the newly prepared 5‐bromo‐2,4‐dichloro‐6‐methylpyrimidine by sequential treatment with ethanolic ammonia and secondary amines. These compounds were successfully reacted with various isothiocyanates in the presence of sodamide in DMF to form the new thiazolo[4,5‐d] pyrimidine derivatives.     

A novel synthesis of 5‐aryl‐3‐phenylpyrazole from 2‐aryl‐3‐benzoyl‐1,1‐cyclopropanedicarbonitrile and hydrazine

A new process for synthesis of 5‐aryl‐3‐phenylpyrazole is achieved. The regioselective ring‐opening reaction of 2‐aryl‐3‐benzoyl‐1,1‐cyclopropanedicarbonitrile with hydrazine plays a crucial role in the described process.     

1,8‐Diazafloren‐9‐one with alkyl and aryl isocyanides in the presence of acetylenic esters: A facile synthesis of γ‐spiroiminolactones

The 1:1 intermediate generated by the addition of alkyl and aryl isocyanides to dialkyl acetylenedicarboxylate is trapped by 1,8‐diazafloren‐9‐one to yield iminolactones in good yields.     

Convenient synthesis of N‐substituted 1‐alkyl and 1‐aryl‐3‐aminoisoquinolines

Cyclocondensation of 2‐acylphenylacetonitriles 1 with amines affords 1‐substituted 3‐aminoisoquinolines 2 in good yields.