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SYSTEMIC APPROACH TO TEACHING AND LEARNING HETEROCYCLIC CHEMISTRY ( SATLHC )

SYSTEMIC APPROACH TO TEACHING AND LEARNING HETEROCYCLIC CHEMISTRY ( SATLHC ). A. F. M. Fahmy , M. A. El-Hashash Faculty of Science, Department of Chemistry and Science Education Center, Ain Shams University, Abbassia, Cairo, EGYPT E-mail: fahmy@online.com.eg W.A.Abduo

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SYSTEMIC APPROACH TO TEACHING AND LEARNING HETEROCYCLIC CHEMISTRY ( SATLHC )

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  1. SYSTEMIC APPROACH TO TEACHING AND LEARNING HETEROCYCLIC CHEMISTRY (SATLHC) A. F. M. Fahmy, M. A. El-Hashash Faculty of Science, Department of Chemistry and Science Education Center, Ain Shams University, Abbassia, Cairo, EGYPTE-mail:fahmy@online.com.eg W.A.Abduo National research Center ,Cairo,Egypt 2008

  2. The linear representation (1a) Vis systemic representation (1b) of concepts. Fig: 1a concept concept concept concept concept Fig: 1b concept concept concept

  3. SD1 SD2 SD0 SDf • Systemic Teaching Strategy: we started teaching of any unit by Systemic diagram (SD0) that has determined the starting point of the unit, and we ended with a final systemic diagram (SDf) and between both we crossover several Systemics(SD1,SD2,...) Fig (2):Systemic teaching strategy

  4. SATLHC Pure Applied - Synthesis - Pharmaceuticals - E-Substitution - Food Additives - Nu-Substitution - Plant growth regulators - Addition - Insecticides - Cycloaddaition - Herbicides - Ring Opening - Corrosion Inhibitors X - Het. Int. Conversion - Super conductors. - Dyes - Photographic materials Z etc..) Het. Z Z X,Y,E,F F Het. Y Het. (Functional Groups) Z Z = N, O, S Het. Z Het. [LATLHC] E [SATLHC]

  5. Application of SATL In Heterocyclic Chemistry: • A course on heterocyclic chemistry using the SATL technique was organized and taught to 3rd year students at Ain Shams University. A portion of the one-semester course (10 lectures, 20 hours) was taught to students during the academic years. • 1999/2000, 2000 / 2001, and 2003 / 2004

  6. Linear VS Systemic Study in Heterocyclic Chemistry: • Linear study in heterocyclic chemistrymeans servay study on the reactivity of the heterocycles to give products in a separate chemical reactions(Alkylation, acylation, Nitration, Sulphonation, formylation, …..). • Systemic study in heterocyclic chemistrymeansservay study on the reactivity of both heterocycles and substituents and their all possible chemical relations.

  7. G Z Reactivity of Reactivity of the Substituents the Nucleus Heteroatom: [(Z) = NH, O, S] Substituents:[(G) = R, - CH2 - X, - X, -CH2 - OH - NH2, - CHO, - COR, - COOH]

  8. Figure 3: summarizes comparative reactivites of the five membered heterocycles as model heterocyclic compounds, and their possible relations.

  9. The diagram (4) represents the reactivity of heterocyclic nucleus, and gives the linear separated chemical relations between (pyrrole, furan, thiophene), and their compounds. • We use heterocyclic chemistry to illustrate, again, how a subject can be organized systemically. SD1 summarizes the comparative reactivities of both heterocyclic nucleus and substituents.

  10. In the systemic diagram (SD1) there are unknown chemical relations (1-7) between heterocyclic compounds. • These relations will be clarified later during the study of pyrrole, furan and thiophene.

  11. ASSESSMENT – I ON SD1 QI) Draw systemic diagrams illustrating the chemical relations between compounds in each of the following sets.

  12. A I - 1

  13. QII) Complete the following systemic diagrams: A II - 2

  14. Cl CHO N N H N N CH3Li / i) DMF/POCl3 ii) aq. Na2CO3 H H2/Rany Ni CH2Cl2 + - red. CO2NH4 N CHCl3/base H CH2OH HCHO (NH4)2CO3 N 130c Sealed Vessel H NaOH RMgX NBS R THF N + - Br N N i) C6H5NSO3 H H H ii)HCl + PhN2 AcONO2 Ac2O -10C i) RCONR2 ii) NaOAc SO3H N N2 Ph N H H NO2 N H COR N H Reactions of pyrrole, and Pyrrole compounds(asExample) I-Pyrrole: (Prerequisites SD1) • We can summarize the reactions of pyrrole in the following diagram (Fig. 4).

  15. The diagram (Fig. 4) represents the reactivity of (pyrrole nucleus), and gives the linear separated chemical relations between pyrrole and its compounds. • We can illustrate the chemical relations in (Fig. 4) systemically by modification of SD1 to SD2(Z = NH):

  16. Reduction Oxid. Wolff/ Kishner red. ? CHO N (3) H Cl N i)DMF/POCl3 ii) aq.Na2CO3 R=CH3 CH2Cl2/ CH2OH N N CO2NH4 N H CH3Li H (8) HCHO ? (NH4)2CO3 R=CH3 CHCl3/ base ? base (1) 130oc RMgX heat COOH N R 200oC N H i) R`CONR2/POCl3 ii) NaOAc N + PhN2 (4) (2) H ? ? + - i) C6H5NSO3 ii) HCl (5) N N2Ph N COR` AcONO2 ? H H Ac2O,-10oc N SO3H H NBS/THF ? N NO2 (6) H Br N SD 2 H ? (7) • Systemic diagram (SD2) shows know chemical relations between pyrrole and its compounds. We have the unknown chemical relations between pyrrole compounds (1-8), and should be clarified during the study of pyrrole compounds.

  17. KMnO4 R= CH3 aq. alkaline KMnO4 H2/Pd Oxid CHO N hydrolysis Cl Vap. Phase decarbonylation H (R= CH3) Ag2CO3/Celite N N LTA/AcOH,  NaBH4 CH2Cl2 / CH3Li i) DMF/poCl3; ii)aq Na2 CO3 CHBr2 CHCl3/ N N N base CH2OH H H H H2-Rany Ni CH2O/ R=CH3 R=CH3 150-200C hydro NBS,CHCl3 refulx NaOH N CO2NH4 Diborane H (NH4)2CO3 RMgx heat Alkylation 200c R N N CO2H + H PhN2 N H i) R`CONR2/POCl3 ii) aq. Na2CO3 + PhN2 H Wolff- kishner red. N NBS/THF i) C6H5NSO3 ii) HCl N2Ph H AcONO2 bromination SOCl2/ N Ac2O-10C COR` Br pyridne N N SO3H H H H Nitration COCl red N NO2 N H H N NH2 NaN3 H Curtius N CON3 rearang. SD 3 H R = CH3 Oxid., chromic acid • After Study of pyrrole compounds [G = R, CH2OH, CHO, RCO, COOH , NH2): We can modify (SD 2 to SD 3) by adding chemical relations (1 – 7).

  18. 1- , , N N N COOH CHO H H H 2- , , , N N N NO2 COOH CHO N H H H H 3- , , , N N N COONH4 N2Ph N COOH H H H H ASSESSMENT – II ON SD3 QI) Draw systemic diagrams illustrating the chemical relations between compounds of each of the following sets: (clockwise)

  19. COOH N H aq. alk. heat 200oC KMnO4 i)DMF, POCl3 ii) aq. Na2 CO3 N N CHO H H A I - 1

  20. ......... DMF , POCl3 aqNa2CO3 N N CHO H H aq.alk. KMnO4 ......... ......... ......... ......... N COOH H AcONO2/ .......... .......... Ac2O- 10C heat ........ 200c .......... .......... COOH N H curtius rearrangement NaN3 SOCl2 .......... .......... QII) Complete the following systemic diagrams: 1- 2- • Then give the systemic chemical relations in a list

  21. CHO COOH N N N H H H Br COOH N N N H H H CHO COOH N N N H H H CHO COOH Br N N N N H H H H Vap. phase decarbonylation i) DMF, POCl3 ii) Na2 CO3 N N CHO H H heat, 200c aq. alk. KMnO4 NBS, THF bromination N N Br COOH H H A II - 2 Above chemical relations in a list:

  22. , , CHO N N N CH3 H H H , COOH N N NO2 H H CH3 MgX ........ ........ ........ LTA/ AcOH  ........ ........ ........ ........ Oxid alk. KMnO4 ........ ........ QIII) Arrange the following compounds in the right places in the following (SD.):

  23. Diborane Chromic acid CH3 N N CH2OH H H + PhN2 N2Ph N N COOH H H QIV) How can you make the following conversions: 1) Pyrrole to pyrrole -2-carboxylic acid. 2) 2-Hydroxymethylpyrrole to 2-phenylazopyrrole. 3) Pyrrole -2-carboxylic acid to 2-bromopyrrole. 4) 2-Methylpyrrole to pyridine. 5) 2- Formyl pyrrole to 2-Nitropyrrole. 6) Pyrrole -2- Carboxylic acid to 2-aminopyrrole. A IV - 2 A IV - 4

  24. NBS/THF N Br N H H (NH4)2 CO3/ 130C Seald vessel heat Br2 200C NBS/THF COOH N N H H hydrolysis (NH4)2 CO3/ 130C Seald vessel COONH4 N COOH N heat Br2 H H 200C hydrolysis COONH4 Br N N H H QV) Rearrange the compounds in the following SD to give correct chemical relations: AV)

  25. QVI) Which of the following systemics are true and which are fals: AVI) a: (x); b: () c: (x); d: ()

  26. QVII) Put () Infront of the correct systemics: The systemic diagram represents the correct chemical relations between pyrrole and its compounds is one of the following: AVI) a: (x); b: (x) c: (); d: (x)

  27. Systemic Teaching Strategies For Uses Of Heterocycles In Synthesis 1- Heterocyclic derivative to another Hetercyclic derivative: Example:

  28. 2- Aliphatic compound to another aliphatic compound via Heterocycle:

  29. 3- Heterocycles to homocycles:

  30. Conclusion: • After the experimentation of SATLHC in Egypt we reached to the following conclusions: 1)SATLHC improved the students ability to view (HC) from a more global perspective. 2)SATLHC helps the students to develop their own mental framework at higher-level cognitive processes (application, analysis, and synthesis). 3)SATLHC increases students ability to learn subject matter in a greater context. 4)SATLHC increases the ability of students to think globally.

  31. References: (1) Taagepera, M.; Noori, S.; J. Chem. Educ. 2000, 77, 1224. (2) Fahmy, A. F. M.; Lagowsik. J. J.; J. Chem. Educ. 2003, 80, (9), 1078. (3) Fahmy, A. F. M., El-Shahaat, M. F., and Saied, A., International Workshop on SATLC, Cairo, Egypt, April (2003). (4) Fahmy, A.F.M., Lagowski, J.J.; Systemic Approach in Teaching and Learning Aliphatic Chemistry; Modern Arab Establishment for printing, publishing; Cairo, Egypt (2000). (5) Fahmy A. F. M., El-Hashash M., Systemic Approach in Teaching and Learning Heterocyclic Chemistry. Science Education Center, Cairo, Egypt (1999). (6) Fahmy A. F. M., Hashem, A. I., and Kandil, N. G.; Systemic Approach in Teaching and Learning Aromatic Chemistry. Science, Education Center, Cairo, Egypt (2000). (7) Fahmy, A. F. M.; Hamza M. S. A; Medien, H. A. A.; Hanna, W. G., M. Abedel-Sabour; and Lagowski; J. J.; Chinese J. Chem. Edu., 23 (12) 2002, 12, 17th IEEC, Beijing August (2002).

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