Solvent-Free Synthesis of Fused Pyrazolo[1,5-a]pyrimidines by Reaction of 5-Amino-1H-pyrazoles and -Triketones

نویسندگان

  • Jairo Quiroga
  • Jaime Portilla
  • Silvia Cruz
  • Braulio Insuasty
  • Manuel Nogueras
  • Justo Cobo
  • Mike Hursthouse
چکیده

The solvent-free reaction between 5-amino-1H-pyrazoles and -triketones (2-acetyldimedone and 2acetylindandione) leads to the formation of new fused pyrazolo[1,5-a]pyrimidines in good yields. A possible mechanistic route is postulated on the basis of the isolation of the cyclization intermediate. The structures and regiospecificity of the reaction were determined on the basis of nmr measurements and X-ray diffraction.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

A simple, solvent-free four-component domino synthesis of 1H-pyrazolo [1, 2-b] phthalazine-5, 10-dione derivatives catalyzed by copper (II) oxide

An eco-safe and facile multi-component domino reaction has been described for the synthesis of 1H-pyrazolo [1, 2-b] phthalazine-5, 10-dione derivatives. The products were obtained by a four-component condensation reaction between phthalimide, hydrazine monohydrate, aromatic aldehyde derivatives and malononitrile in the presence of a catalytic amount of copper (II) oxide (CuO) ...

متن کامل

Regioselectivity of 1,3-dipolar cycloadditions and antimicrobial activity of isoxazoline, pyrrolo[3,4-d]isoxazole-4,6-diones, pyrazolo[3,4-d]pyridazines and pyrazolo[1,5-a]pyrimidines.

BACKGROUND Isoxazoles exhibit interesting biological activities, and the 1,3-dipolar cycloaddition(13DC) reactions play an important role in both mechanistic and synthetic organic chemistry. Pyrazoles and annulated pyrazoles exhibit some diverse biological activities. They are used as antipyretic, analgesic drugs, tranquilizing, and herbicidal agents. Pyrazoles are also used extensively as usef...

متن کامل

Green one pot solvent-free synthesis of pyrano[2,3-c]-pyrazoles and pyrazolo[1,5-a]pyrimidines.

Pyrano[2,3-c]pyrazoles are obtained via mixing ethyl acetoacetate, hydrazine hydrate, aldehydes or ketones and malononitrile in the absence of solvent. These same products were also obtained by reacting arylidenemalononitriles 3 with 3-methyl-2-pyrazolin-5-ones. NOE difference experiments confirmed that these products exist solely in the 2H form. Similar treatments of 3-amino-2-pyrazolin-5-one ...

متن کامل

Cellulose sulfuric acid catalyzed multicomponent reaction for efficient synthesis of pyrimido and pyrazolo[4,5-b]quinolines under solvent-free conditions

Cellulose sulfuric acid was used as an efficient biopolymer-based catalyst for the synthesis of tetrahydropyrimido[4,5-b]quinoline-2,4,6-triones and hexahydro-2H-pyrazolo[5,4-b]quinoline-6-ones via three component reaction of aldehyde, 5,5-dimethyl-1,3-cyclohexadione and 6-amino-1,3-dimethyluracil or 5-amino-3-methyl-1-phenypyrazole under solvent-free conditions at 90 oC. The major advantages o...

متن کامل

Cellulose sulfuric acid catalyzed multicomponent reaction for efficient synthesis of pyrimido and pyrazolo[4,5-b]quinolines under solvent-free conditions

Cellulose sulfuric acid was used as an efficient biopolymer-based catalyst for the synthesis of tetrahydropyrimido[4,5-b]quinoline-2,4,6-triones and hexahydro-2H-pyrazolo[5,4-b]quinoline-6-ones via three component reaction of aldehyde, 5,5-dimethyl-1,3-cyclohexadione and 6-amino-1,3-dimethyluracil or 5-amino-3-methyl-1-phenypyrazole under solvent-free conditions at 90 oC. The major advantages o...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2008