Oxazines Oxazoles

Keywords Azepines Benzimidazoles Benzofurans Benzopyranones Benzothlazoles Benzothiophenes Benzoxazoles Benzoxocanes DIoxepanes Dioxocanes DIoxolanes Dithiiranes Dithioles Furans Imidazoles Indazoles Indoles Indollnes Indollzines Isoquinolines Isoxazoles Isoxazolines Oxazines Oxazoles Oxepanes Oxiranes Pyrazines Pyrazoles Pyridazines Pyridines Pyrimidines Pyrroles Pyrrolidines Pyrrolines Pyrrolizines Quinolines Thietanes Thiophenes Triazoles... 

Oxazolo[4,3-c][l,4]oxazine, perhydro-conformation, 6, 662 Oxazolo[2,3-h]oxazoles synthesis, 6, 989 Oxazolophanes synthesis, 7, 774 (3,5)Oxazolophanes synthesis, 7, 770 5ff-Oxazolo[3,2-a]pyrazine synthesis, 6, 664 5f/-Oxazolo[3,2-6]pyridazine synthesis... 

A single isomer of 4-phcnylpcrhydropyrido[2,1 -t][l,4]oxazin-l-one 436 was isolated from a reaction mixture of 2-bromocyclohexane and 2-azido-2-phenylethanol (Scheme 37). The formation of 436 was presumed to be from azepino[l,2-A [l,3]oxazole intermediate 435 by HBr elimination and 1,2-migration <2000JOC3771>. 

Imidazolines are also formed in silver cyanide-catalyzed cyclization of alkyl isocyanides with aliphatic diamines (Scheme 103).169 This simple synthesis can be applied in a general way with difunctional nucleophiles and has been used to prepare benzimidazoles, oxazoles, thiazoles, and oxazines.169 It is suggested that transient carbene complexes are formed in these reactions (cf. 87 in Scheme 103) but further work is required to ascertain the mechanism and scope of these processes. 

Oxamidobis-ethyl(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), 3 115 Oxane bonds, silylation and, 22 702-703 Oxazine soluble dyes, 7 373t Oxaziridines, 9 372-373 2-Oxazolines, microwave-assisted synthesis of, 76 576 Oxazoles, 27 151... 

Hydroxylamines may be acyclic (1) with one or two substituents or cyclic (4). Cyclic compounds 5 where both the nitrogen and the oxygen atoms are ring members like oxaziridines (6), 1,2-oxazetidines (7), tetrahydro-l,2-oxazoles (8) (usually named isoxa-zolidines) and tetrahydro-l,2-oxazines (9) will not be considered in this chapter. Each of these compounds is regarded as a compound class on their own and their chemistry has usually been reviewed individually. 

The photochromic spiroindolinonaphth[2,l-fc][l,4]oxazines conjugated with aza-15(18)-crown-5(6) ether moieties or morpholine in the presence of Pb2+ or Eu3+ give highly coloured betaine merocyanine, the open form of the compound, which can return to the initially closed non-coloured form by irradiation with light (Scheme 125).188 When the merocyanine complexes are kept in the dark, the corresponding oxazole derivatives are formed irreversibly and regioselectively. 

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