Fluorinated nitrogen heterocycles via cyclization. II. 3‐trifluoromethylglutarimides from fluorinated <i>α,β</i>‐unsaturated carbonyls and cyanoacetamide

Portnoy, Seymour

doi:10.1002/jhet.5570030330

Cited by 7 publications

(4 citation statements)

References 7 publications

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“…The infrared spectrum of dinitrile (VIIa) displayed two sharp, weak absorptions at 2255 and 2025 cm-' , both of which may be assigned to the nitrile stretching vibration, while the dinitrile (VIIb) showed only one very weak, broad absorption band at 2250 cm-, also assignable to the nitrile stretching vibration. Such diminution in intensity of this normally strong band has been reported previously when electron-withdrawing groups are adjacent to the carbon atom which bears the nitrile group (8,9).…”

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confidence: 83%

Synthesis of substituted pyridazino[4,5‐c]pyridazines

Singerman

Castle

1967

Journal of Heterocyclic Chem

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Several pyridazino[4,5c Ipyridazines substituted in t h e 5and 8-positions with hydroxyl, mercapto and amino groups and in the 3-position with a methyl group or a hydrogen atom have been prepared. In the course of this work five previously unreported pyridazine derivatives have also been synthesized.The only reported .derivative of pyridazino[4,5c]pyridazine is the compound described by Gault, et al., (1) namely 4,4a,6,7(2H)-tetrahydropyridazino[ 4,5c Ipyrida-

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confidence: 83%

Synthesis of substituted pyridazino[4,5‐c]pyridazines

Singerman

Castle

1967

Journal of Heterocyclic Chem

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“…The infrared absorption band of the nitrile group a t -2250 cm-* is weak in the dinitrile (IX). This has been observed previously (16) when electron-withdrawing groups a r e present adjacent to the carbon atom carrying the nitrile group.…”

Section: 3-d]pyridazinesupporting

confidence: 69%

The synthesis of pyrazino[2,3‐d]pyridazine and some of its derivatives

Patel

Castle

1966

Journal of Heterocyclic Chem

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Pyrazino[2, 3-dlpyridazine (I) w a s synthesized by two different routes. 5.8-Dihydroxypyrazino[2,3-d]pyridazine (IV) was converted to 5,8-dichloropyrazino[2,3-d]pyridazine (V) and 5,8-dibromopyrazino[2,3-d]pyridazine (Va). When V w a s treated with various benzyl mercaptans and alkoxides the corresponding disubstituted derivatives were obtained. Compound V when allowed to react with a r o m a t i c a m i n e s gave 5,8-bisaminopyrazino[2,3-d]pyridazines, however, with aliphatic a m i n e s only mono substituted products w e r e obtained substituted in the 8 -position.The reaction of pyrazine-2,3-dinitrile with hydrazine gave 5,8-diaminopyrazino[2,3-d]pyridazine (X).In the pyrazino[2,3-d]pyridazine (I) ring system only two compounds have previously been reported in the literature namely 5 , 8 -dihydroxyp,yrazino-[2,3-d]pyridazine (IV) (1,2) and 5,U-bis(P-methoxyphenyl)pyrazino[2,3-d]pyridazine (3). T h i s ring is of interest because of the close structural similarity to the pteridine ring system. The title compound (I) was synthesized by two different methods. These w e r e (a) condensation of 4,5-diaminopyridazine (II) (4) with glyoxal in methanol (5) and (b) by dehalogenation of 5 , 8dichloropyrazino[2,3dpyridazine (V) with palladium on charcoal. 2-Methylpyrazino-[ 2 , 3dlpyridazine (111) w a s similarly prepared by allowing I1 to react with pyruvaldehyde.Compound N w a s prepared by a slight modification of Hammerich's procedure (2) by using hydrazine dihydrochloride and water (6) instead of hydrazine hydrate and acetic acid. Similarly Jones' procedure (1) w a s also modified since in o u r hands e r r a t i c results w e r e obtained. We have allowed dimethylpyrazine-2,3-dicarboxylate to react with hydrazine hydrate in methanol under reflux for a longer period of time and the insoluble hydrazonium s a l t w a s dissolved in water and IV w a s precipitated by acid ( 7 ) .Compound N failed to give the diacetate as w a s the case with 5,8-dihydroxypyridino[2,3-d ]pyridazineobserved by Gheorghiu (8), but it gave the monoacetate (ma). Similarly, a monotosylate (IVb) w a s obtained when IV w a s treated with P-toluenesulfonyl chloride in pyridine. The spectroscopic data suggest that IVa and IVb exist in the keto forms. 5 ,U-Dichloropyrazin0[2,~djpyridazine w a s obtained when IV was allowed to r e a c t with a mixture of phosphorus oxychloride and phosphorus pentachloride ( 9 ) . Similarly the 5 , 8dibromopyrazino[2,3 -d ]pyridazine w a s the product when IV w a s treated with phosphorus oxybromide and bromine (10). When V was treated with sodium alkoxides the corresponding 5,U -dial koxypyrazino[ 2 ,Sd] py ridazines (VIa-c) w e r e obtained in good yields (11). Attempts to p r e p a r e 5,8-dimercaptopyrazino[2,3-d]pyridazine CHO 8 1 I CHO Ill 5 4 I Pd -C /Hp CI V OH OH 0-R IVO, R -CHsCOb. R -Tosyl

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“…3-Cyanopiperidin-2,6-diones were obtained before by the addition of deprotonated ethyl cyanoacetate to the α,βunsaturated amides derived from the cinnamic acid analogues (Portnoy 1966). The iridium-catalysed formation of similar glutaric imides was also reported (Takaya et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Environmental-friendly one-pot cascade synthesis of 3-cyanopiperidin-2,6-diones

2019

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3-Cyanopiperidin-2,6-diones are key intermediates in the synthesis of several drugs and natural products. We developed onepot synthesis of 3-cyanopiperidin-2,6-diones by Knoevenagel condensation of cyanoacetic acid and aldehydes, followed by addition of cyanoacetic acid, Achmatowicz reaction and decarboxylation. We tested a wide range of aliphatic and aromatic aldehydes. Products were obtained under simple, environmentally friendly conditions and in yields up to 99%. Substrates were stirred in toluene at reflux, and filtered through short pad of silica gel, and the product was purified by recrystallization.

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Fluorinated nitrogen heterocycles via cyclization. II. 3‐trifluoromethylglutarimides from fluorinated α,β‐unsaturated carbonyls and cyanoacetamide

Cited by 7 publications

References 7 publications

Synthesis of substituted pyridazino[4,5‐c]pyridazines

Synthesis of substituted pyridazino[4,5‐c]pyridazines

The synthesis of pyrazino[2,3‐d]pyridazine and some of its derivatives

Environmental-friendly one-pot cascade synthesis of 3-cyanopiperidin-2,6-diones

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