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RESEARCH PRODUCT

Eight-membered Rings with Two Heteroatoms 1,3

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This chapter deals with heterocine rings with two heteroatoms in a 1,3-relationship, namely 1,3-diazocine, 2H-1,3-oxazocine, 2H-1,3-thiazocine, 4H-1,3-dioxocin, and 4H-1,3-dithiocin. On the 4H-1,3-oxathiocin ring system, belonging to the diheterocine family, in the past decade, no chemistry was reported. This chapter covers the literature from 1996 to 2006 and also reports those articles published in 1995 which were not reported in CHEC-II(1996). In this edition, in addition to the uncondensed derivatives, eight-membered 1,2-heterocycles fused to five-, six-, and seven-membered carbocycles or heterocycles are covered. Bridged heterocines, which actually constitute the majority of the compounds reported, were covered as well. The main change in this chapter, with respect to CHEC-II(1996), is related to the “Theoretical methods” section. Such a section in CHEC-II(1996) was a unique section, placed immediately after the introduction and which dealt with all the classes of eight-membered heterocycles with two heteroatoms. In this edition, each paragraph dealing with a single class of heterocycles has its own theoretical methods section. The “Experimental structural methods” section has received a strong impulse since, with some exceptions, the great majority of the reported derivatives has been adequately characterized. As already done in CHEC-II(1996), all five systems are discussed separately, with each discussion following the same general format. In the case particular sections are not mentioned, it means that no chemistry has been reported.