الفهرس | Only 14 pages are availabe for public view |
Abstract This work is planned to study the behaviour of furan- and pyrrolee2,3.diones towards nucleophilic reactions such as semicarbazones, tluosemicarbazones and to use them as potential precursors through lhennolysis to incorporate a different new heterocyclic compounds in direct and simple way. Synthesis of 1,2_DihyDROPyrimidines: Reaction of furan-2,3-dione 112 with semicarbazones 113 a-d or lhiosemicarbazones 113 e,f in toluene at reflux led to the formation of 4,S_disubstituted-lH-pyrimidines 116 a-f in moderate yields ( 40-650/0 ). u’uthesis of Pyrrole-2,3-Dione: Treatment of the yellow furandione 112 with arylisocyanate 117 a,b at 70’C fUl11ished the corresponding red colour pyrrole-2,3-diones 119 Thermolytic reactions of furan-2,3-dionc with aryllisocyanates, dicyciohexylcarbodiiIllide and iInines: Synthesis of 1,3-0xazines: The reaction of furandione 112 with heterocu11111lenes, arylisocyanates 117 a,b 111 boiling xylene; gave the corresponding 1,33oxazine derivatives 124 a,b in (54-70 0/0) yields. The fOlluation of these 1,3-oxazines 111ay be occured via a [4+2] cyc1oaddition reaction of uuoxoketene and heterocll11111lenes ( Scheme 3 ). |