Structure determination of the N-methyl isomers of 5-amino-3,4-dicyanopyrazole and certain related pyrazolo[3,4-d]pyrimidines

Hecht, Sidney M.; Werner, Dieter; Traficante, Daniel D.; Sundaralingam, M.; Prusiner, P.; Ito, Tetsuo; Sakurai, T.

doi:10.1021/jo00900a029

Cited by 30 publications

(16 citation statements)

References 12 publications

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“…This fact was confirmed by the several strategies. First, by using the technique of Hecht et al [10], who found it was possible to differentiate between the isomeric pyrazoles 5 and 6 based on their different reactivity; thus, treatment of 6 with acetic anhydride in pyridine at room temperature afforded the corresponding N -acetyl derivative, but pyrazole 5 did not form the corresponding derivative under the same conditions, although it did form at 50-60°C (Scheme 2). …”

Section: Resultsmentioning

confidence: 99%

Heterocyclic o-Aminonitriles: Preparation of Pyrazolo[3,4-d]-pyrimidines with Modification of the Substituents at the 1- Position

Al-Afaleq¹,

Abubshait²

2001

Molecules

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Novel 1-[6-(p-tolyl) pyridazin-3-yl]pyrazole-o-aminonitriles (3a-c) were formed using 3-hydrazino-6-(p-tolyl)pyridazine (2) and ketene S,S-acetals (1a), S,N-acetals (1b) or tetracyanoethylene (1c). The pyrazole-o-aminonitriles (3a-c) were in turn used as precursors for the preparation of previously unreported 1-[6-(p-tolyl)-pyridazin-3-yl]pyrazolo[3,4-d]pyrimidines (8, 9, 13-20) and 7-[6-( p-tolyl) pyridazin-3-yl]2-arylpyrazolo[3,4-d]1,2,4-triazolo[5,1-f]pyrimidines (10-12) which are expected to possess considerable chemical and pharmacological activities.

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Section: Resultsmentioning

confidence: 99%

Heterocyclic o-Aminonitriles: Preparation of Pyrazolo[3,4-d]-pyrimidines with Modification of the Substituents at the 1- Position

Al-Afaleq¹,

Abubshait²

2001

Molecules

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“…In an attempt to synthesize 3-amino-4-ethoxycarbonyl-pyrazole 92 via reacting 91 with hydrazine hydrate in a manner similar to that reported for its reaction with phenyl hydrazine which is established to afford pyrazole derivatives, Midorikawa et al [123,124] 3,4-Dicyano-5-aminopyrazoles have been synthesized by taking the advantage of the tetracyanoethylene 23 for Michael addition. Thus, aryl and alkyl hydrazones as well as hydrazides, semicarbazides and thiosemicarbazides have been reported to react with tetracyanoethylene to afford 1-substituted-4,5-dicyano-3-aminopyrazoles [145]. The structure assigned for the reaction product of 23 with methylhydrazine was reinvestigated by Hecht et al [145] and Earl et al [146] in two separate contributions.…”

Section: Scheme 29mentioning

confidence: 99%

“…Thus, aryl and alkyl hydrazones as well as hydrazides, semicarbazides and thiosemicarbazides have been reported to react with tetracyanoethylene to afford 1-substituted-4,5-dicyano-3-aminopyrazoles [145]. The structure assigned for the reaction product of 23 with methylhydrazine was reinvestigated by Hecht et al [145] and Earl et al [146] in two separate contributions. It has been shown by Hecht et al [145] that consideration of the mechanistic routes suggested in literature for this reaction illustrates the source of structural ambiguity in the formation of these products from methylhydrazine and 23.…”

Section: Scheme 29mentioning

confidence: 99%

“…The structure assigned for the reaction product of 23 with methylhydrazine was reinvestigated by Hecht et al [145] and Earl et al [146] in two separate contributions. It has been shown by Hecht et al [145] that consideration of the mechanistic routes suggested in literature for this reaction illustrates the source of structural ambiguity in the formation of these products from methylhydrazine and 23. Thus, one might for example, envision formation of the 1-methyl-4,5-dicyano-3-aminopyrazole 105 by conjugate addition of the more nucleophilic substituted hydrazine nitrogen of the hydrazine to the cyano group, affording the observed product is depicted in scheme 34.…”

Section: Scheme 29mentioning

confidence: 99%

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The Chemistry of Alkenyl Nitriles and its Utility in Heterocyclic Synthesis

Elgazwy¹

2013

Organic Chem Current Res

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including purines [7,8], pyrimidines [9], pyrazines [10] (some which are widely employed in the fluorescent dye industry [11]), imidazoles [12], biphenylenes [13], porphyrazines (which have great potential in optical sensor technology) [14] and diimines that are used as catalysts [15]. This review highlights the alkenyl nitrile chemistry with the focus on the utility of heterocyclic compounds. The synthesis and chemistry of the highly strained aryl nitrile is also briefly reviewed [16]. Heterocycles are ubiquitous in all kind of compounds of interest, and among all the possible synthetic methods of achieving their introduction into an structure, probably the use of a alkenyl nitrile analogue is the most direct one. The present review deals with the generation and synthetic uses of alkenyl nitriles and aryl nitriles formed in heterocyclic synthesis, and can be considered as an update of our revision published in 2007 on this topical [17]. Therefore, only references published from the second quarter of 2003 until the third quarter of 2010 are included, and the same restrictions to the literature coverage applied. Thus, only heterocycles compounds which are found applicability are considered. As previously, the present review is organized by the type of ring members and subdivided by the type of heterocycles fused compounds, including methods for their preparation and their synthetic uses. New developments in the utilities of some alkenyl nitriles in heterocyclic synthesis are reviewed. General synthetic routes based on the utilization of alkenyl nitriles of active imines are discussed. The major methods and modifications are analyzed [18-21]. In this review, which covers the literature up to date, we describe the new and improved methods for the construction of the skeletons, with a particular emphasis on the four, five and six membered ring of heterocyclic compounds. Some of these procedures have clear technical advantages over older methods in terms of yield and versatility, but do not employ new chemistry in the construction of the ring systems. The

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“…Therefore, the resulting molecule could be an asymmetric chromophore exhibiting secon-order nonlinear optical properties. Reactions of tetracyanoethylene with substituted hydrazines were reported [11,12]. Its molecule is characterized by conjugated bond system, and reaction of an amine at one of the four cyano groups should considerably reduce the degree of symmetry.…”

Section: Rnh 2 + R'c N R'c(=nh)nhrmentioning

confidence: 99%

Reactions of primary amines with tetracyanoethylene

et al. 2004

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Primary amines, 3-triethoxysilylpropylamine, 3-silatranylpropylamine, and cyclohexylamine, react with tetracyanoethylene in acetonitrile at room temperature via addition at the cyano group to afford the corresponding amidines. N-Cyclohexyltricyanoacrylamidine exists as a mixture of two of the three possible isomers, while N-(3-triethoxysilylpropyl)tricyanoacrylamidine and N-(3-silatranylpropyl)tricyanoacrylamidine exist mainly as a single isomer containing NH 2 group. N-(3-Triethoxysilylpropyl)tricyanoacrylamidine was used to prepare gels and films.

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Structure determination of the N-methyl isomers of 5-amino-3,4-dicyanopyrazole and certain related pyrazolo[3,4-d]pyrimidines

Cited by 30 publications

References 12 publications

Heterocyclic o-Aminonitriles: Preparation of Pyrazolo[3,4-d]-pyrimidines with Modification of the Substituents at the 1- Position

Heterocyclic o-Aminonitriles: Preparation of Pyrazolo[3,4-d]-pyrimidines with Modification of the Substituents at the 1- Position

The Chemistry of Alkenyl Nitriles and its Utility in Heterocyclic Synthesis

Reactions of primary amines with tetracyanoethylene

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