Abstract
This thesis includes four parts. The first part deals with the reaction of hydralazine 1 with carbonyl compounds. Our studies showed that N-1 and N-3 of 1 are the most active nitrogen atoms in this molecule. It was also found that the pass way of the reactions depended on the pH as well as the solvent. A novel eight member heteroannelated system derived from 1 was discovered. It was found to be involved in ring-chain tautomerism, namely 6,7-dihydro-7-hydroxy-12H-phthalazino{2,1-b}{2,4}benzodiazocin-12-one, and 2-(2-formylbenzoyl)-1-hydrazono-1,2-dihydrophthalazine. Tautomerism involving substituents at the hydrazino group of 1 was studied by lR, ('1)H-NMR and ('13)C-NMR spectroscopy. Annelation reactions of five(s-triazolo) and six(as-triazino) membered rings to hydralazine 1 were investigated. Part II deals with the chemistry of (alpha)-keto-(beta)-substituted-(gamma)-butyrolactones, 2. A comprehensive study on annular prototropy of type 2 compounds in CDCl(,3) and Me(,2)SO-d(,6) was achieved utilizing proton and carbon-13 spectroscopy. The condensation reaction between 2 and O-phenylenediamine leads under retrograde aldol condensation to 3-substituted-3,4-dihydro-2(1H)quinoxalinones, as a new convenient synthesis of this type of heterocyclic system. The reaction of type 2 compounds with different arylenediamines was also studied and the structures of the products from these reactions were provided by ('1)H-NMR, ('13)C-NMR, MS and lR spectroscopic studies. A highly efficient method for the synthesis of 3-halo-2-arylfuro{2,3-b}quinoxalines has been devised. In Part III we studied the reaction of dehydro-L-ascorbic acid, 3 with o-phenylenediamine followed by treatment with hydralazine or semicarbazide to give 3-{L-threo-2,3,4-trihydroxy-1-hydralazono-(or semicarbazono)butyl}-2-quinoxalinones 3 or 4, respectively. Periodate oxidation of 4 suspended in an aqueous solution of sodium metaperiodate afforded 3-(1-semicarbazono-glyoxal-1-yl)-2-quinoxalinone, 5. On the other hand, oxidation of 4 with periodic acid in a solution of 1,4-dioxan-methanol gave unexpectedly the acetalated product of 5. In Part IV alkyl- and arylaminotriphenylphosphonium halides, 6 react with elemental halogens or interhalogen compounds to afford alkyl- or arylaminotriphenylphosphonium trihalides 7. The assignment of a trihalide structure to these compounds was based on ('31)P-NMR, and on lR- and Raman spectroscopic evidence.