Introduction
Enaminone derivatives are highly reactive intermediates extensively used for synthesis of otherwise not readily obtainable, heterocyclic compounds [1-4] and it can be used as starting material for the preparations of N-1 and /or N-2 substituted pyrazoles [29-31]. On the other hand a great deal of interest has been focused on the synthesis of the functionalized pyridine derivative owing to their biological activities [5-8].
In view of these observations and in continuation of our previous work directed towards development synthetic approach for the construction of biologically active heterocycles[9-12], we report herein a facile rout to various pyrazoles , isoxazoles, pyrimidines, pyrazolopyrimidine and triazolopyrimidine incorporated into pyridine moieties at position 2 and 6.
In this manner we have found that 2, 6-Bis [3-oxo-3-propanenitrile-2-(N, N-dimethyl amino) methylene] pyridine (3) is an excellent bulding blook for the synthesis of the entiled objectives
Results and discussion
Treatment of 2,6-Bis(3-oxo-3-propanenitrile) pyridine(2) with dimethyl formamide – dimethyl acetal (DMF-DMA) in dry THF at room temperature afforded a yellow crystalline product identified as 6-bis [3-oxo-3-propanenitrile-2-(N, N-dimethyl amino) methylene] pyridine (3)(scheme 1).
Scheme 1
The reactivity of the enaminonitrile 3 towards some nitrogen nucleophiles was investigated. Thus, treatment of compound 3 with hydrazine hydrate in refluxing ethanol, afforded a colourless prouduct for which three possible structures 4a, 5a and 6a can be formulated. The spectral data of the isolated product was in complete agreement with structure 4a. Similarly, compound 3 reacted with phenyl hydrazine in refluxing ethanol in the presen...
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2,6-Bis[6-cyano-2-phenylpyrazolo[1,5-a]pyrimidin-7-yl]pyridine( 13)
Yield (0.423g, 82 %), mp:280 o C. IR (KBr) v cm-1: 2215 (CN),
1HNMR (DMSO-d6):
MS m/z (%): 515(M+), 346 315 (17), 77 (100). Analysis for C 31H 17 N 9 (515.54), Calcd: C, 72.22; H, 3.32; N, 24.45. Found: C, 72.25 H 3.37, N, 24.40.
2,6-Bis[5-cyano-pyrimido[1,2-a]benzimidazol-6-yl]pyridine(18)
Yield(0.405g,87 %), mp: 285 o C. IR (KBr) v cm-1: 2198, (CN).
1HNMR (DMSO-d6):
MS m/z (%):346 (M+, 68), 315 (17), 77 (100).
Analysis for C 27H 13 N 9 (463.45) Calcd: C, 69.97; H, 2.83; N, 27.20. Found: C, 70.10 H, 2.85; N, 27.25.
2,6-Bis[6-cyano-[1,2,4]triazolo[1,5-a]pyrimidin-7-yl]pyridine(21)
Yield (0.295g, 81 %), mp: ----o C.
IR (KBr) v cm-1:
1HNMR (DMSO-d6):
MS m/z (%):
Analysis for C 17H 7 N 11 (365.31), Calcd: C, 55.89; H, 1.93; N, 42.18. Found: C, 62.30; H, 4.10; N, 24.20.
Ramachandria, C. T., Subramanyan, N., Bar, K. J., Baker, G., & Yeragani, V. K. (n.d.).
This week’s lab was the third and final step in a multi-step synthesis reaction. The starting material of this week was benzil and 1,3- diphenylacetone was added along with a strong base, KOH, to form the product tetraphenylcyclopentadienone. The product was confirmed to be tetraphenylcyclopentadienone based of the color of the product, the IR spectrum, and the mechanism of the reaction. The product of the reaction was a dark purple/black color, which corresponds to literature colors of tetraphenylcyclopentadienone. The tetraphenylcyclopentadienone product was a deep purple/black because of its absorption of all light wavelengths. The conjugated aromatic rings in the product create a delocalized pi electron system and the electrons are excited
This paper describes the methods used in the identification, investigation of properties, and synthesis of an unknown compound. The compound was identified as calcium nitrate by a variety of tests. When the compound was received, it was already known to be one of twelve possible ionic compounds. The flame test identified the presence of the calcium anion in the compound. The compound tested positive for the nitrate cation using the iron sulfate test. At this point it was hypothesized that the compound was calcium nitrate. Reactivity tests and quantitative analysis comparing the unknown compound with calcium nitrate supported this hypothesis. Synthesis reactions were then carried out and analyzed.
A weak peak was at a position between 1600-1620 cm-1 can also be seem in the IR, which was likely to be aromatic C=C functional group that was from two benzene rings attached to alkynes. On the other hand, the IR spectrum of the experimental diphenylacetylene resulted in 4 peaks. The first peak was strong and broad at the position of 3359.26 cm-1, which was most likely to be OH bond. The OH bond appeared in the spectrum because of the residue left from ethanol that was used to clean the product at the end of recrystallization process. It might also be from the water that was trapped in the crystal since the solution was put in ice bath during the recrystallization process. The second peak was weak, but sharp. It was at the position of 3062.93 cm-1, which indicated that C-H (sp2) was presence in the compound. The group was likely from the C-H bonds in the benzene ring attached to the alkyne. The remaining peaks were weak and at positions of 1637.48 and 1599.15 cm-1, respectively. This showed that the compound had aromatic C=C function groups, which was from the benzene rings. Overall, by looking at the functional groups presented in the compound, one can assume that the compound consisted of diphenylacetelene and ethanol or
First, A (3.348 g, 0.031 mol) and triethylamine (6.060 g, 0.060 mol) were added to a glass flask. Then, B (5.850 g, 0.030 mol) was added dropwise to the resulting reaction mixture over a period of 2 h, and the temperature was maintained at 5 °C. The reaction mixtures were carefully maintained at 80 °C for another 5 h. Finally, the reaction mixture was washed with diethyl ether, separated by reduced pressure suction filtration, and dried in a vacuum oven at 100 °C for 12 h to afford a white solid powder, namely, poly-N-aniline-phenyl phosphamide (PDPPD) in 93%
The goal of this lab is to synthesize maleic anhydride with polyethylene glycol of 200g/mol molecular weight (PEG 200) and 2,3-dimethyl-1,3-butadiene to get 4,5-dimethylcyclohexane-1,2-dicarboxylic acid anhydride and its diacid by using Diels-Alders reaction and hydrolysis, respectively. The crystals were determined using melting point determination and IR spectroscopy.
Results: Through a melting point reading, it was determined that the product obtained was 2,4-Dibromoanisol mp 55-58 C. The products obtained by my partners, were determined to be: (p-bromoacetanilide mp 160-165 C) and (2,4,6 tribromoaniline, mp of 108-110 C) respectively.
In this lab 4-tert-butylcyclohexanone is reduced by sodium borohydride (NaBH4) to produce the cis and trans isomers of 4-tert-butylcyclohexanol. Since the starting material is a ketone, NaBH4 is strong enough to perform a reduction and lithium aluminum hydride is not needed. NaBH4 can attack the carbonyl group at an equatorial (cis) or axial (trans) position, making this reaction stereoselective. After the ketone is reduced by the metal-hydride, hydrochloric acid adds a proton to the negatively charged oxygen to make a hydroxyl group. The trans isomer is more abundant than the cis based on the results found in the experiment and the fact that the trans isomer is more stable; due to having the largest functional groups in equatorial positions.
...Hallert, C., C. Grant, S. Grehn, C. Grannot, S. Hultent, G. Midhagens M. Strom, H. Svensson,
The purpose of this experiment is to determine the absolute configuration of an unknown chiral secondary alcohol using the competing enantioselective conversion (CEC) method. This method uses both R- and S- enantiomers of a chiral acyl-transfer catalyst called homobenzotetramisole (HBTM), in separate parallel reactions, and thin layer chromatography to identify the stereochemistry of the secondary alcohol, whether it be an R- or S- enantiomer. Quantitative analysis was performed using a program called ImageJ after the appropriate picture was taken of the stained TLC plate. The molecular structure of the unknown alcohol was identified using 1H NMR spectroscopy by matching the hydrogens to the corresponding peak.
9(3): 383-398. Keeney, Belea T. and Kathleen M. Heide. 1995.
5. A. Mathur, E. Franco, J. Leone, H. Osman-Mohamed, H. Rojas, N. Kemmer, G. Neff,
Ward, D. E., Jemal, D. A., Cokkinides, D. V., Singh, D. G., Cardinez, C., Ghafoor, A., et al. (2008, December 31). . Wiley Online Library. Retrieved April 29, 2014, from http://onlinelibrary.wiley.com/doi/10.3322/canjclin.54.2.78/full
Thickett, Geoffrey. Chemistry 2: HSC course. N/A ed. Vol. 1. Milton: John Wiley & Sons Australia, 2006. 94-108. 1 vols. Print.
Pauly, S. (2011, February). News from ABC: changes and challenges. Analytical & Bioanalytical Chemistry. pp. 1003-1004. doi:10.1007/s00216-010-4459-0.